阅读说明：本技术 构成光纤放大器的光器件、光纤放大器以及制造方法 (Optical device constituting optical fiber amplifier, and method of manufacturing the same ) 是由 操时宜 常志武 李淑杰 于 2020-06-04 设计创作，主要内容包括：本申请提供了一种构成光纤放大器的光器件、光纤放大器以及制造方法。该光器件采用第一光纤与增益光纤连接,或者,该光器件直接连接增益光纤；该光器件采用第二光纤与光纤放大器中的一个或多个第二光器件连接,和/或,采用第二光纤输入光信号或输出增益光纤放大后的光信号；其中,第一光纤和第二光纤的软化温度和/或折射率不同,或者,增益光纤和第二光纤的软化温度和/或折射率不同。通过本申请,可以根据需求设计光器件的尾纤,从而可以提高光纤放大器的应用灵活性,提高光纤放大器的使用性能。如在某些设计中,可以大大降低光纤连接处的损耗,进而提升光放增益。(An optical device constituting an optical fiber amplifier, and a manufacturing method are provided. The optical device is connected with the gain optical fiber by adopting a first optical fiber, or the optical device is directly connected with the gain optical fiber; the optical device is connected with one or more second optical devices in the optical fiber amplifier by adopting a second optical fiber, and/or an optical signal is input into the optical device by adopting the second optical fiber or an optical signal amplified by the output gain optical fiber; wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indexes, or the gain optical fiber and the second optical fiber have different softening temperatures and/or refractive indexes. Through the method and the device, the tail fiber of the optical device can be designed according to requirements, so that the application flexibility of the optical fiber amplifier can be improved, and the use performance of the optical fiber amplifier can be improved. For example, in some designs, the loss at the fiber connection can be greatly reduced, thereby improving the gain of the optical amplifier.)

1. An optical device, for use in an optical fiber amplifier,

the optical device is connected with a gain optical fiber by adopting a first optical fiber, or the optical device is directly connected with the gain optical fiber, wherein the gain optical fiber is used for amplifying an optical signal;

the optical device is connected with one or more second optical devices in the optical fiber amplifier by adopting a second optical fiber, or an optical signal is input into the optical fiber or an optical signal amplified by the gain optical fiber is output by adopting the second optical fiber;

wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indices, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

2. The optical device according to claim 1,

the absolute value of the difference between the softening temperatures of the first optical fiber and the second optical fiber is greater than the absolute value of the difference between the softening temperatures of the first optical fiber and the gain optical fiber; and/or the presence of a gas in the gas,

the absolute value of the difference in refractive index between the first optical fiber and the second optical fiber is greater than the absolute value of the difference in refractive index between the first optical fiber and the gain optical fiber.

3. The light device according to claim 1 or 2,

the optical device reaches the first optical fiber or the gain optical fiber through at least one section of free space through an optical signal input by the second optical fiber; alternatively, the first and second electrodes may be,

the optical device is used for transmitting an optical signal input by the first optical fiber or the gain optical fiber to the second optical fiber at least through a section of free space.

4. A light device as claimed in any one of claims 1 to 3, comprising at least one capillary for introducing into the light device one or more of: the first optical fiber, the second optical fiber, the gain optical fiber.

5. The light device according to any one of claims 1 to 4,

the first optical fiber and the gain optical fiber are connected in a fusion mode.

6. The light device according to any one of claims 1 to 5,

the optical device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter,

the optical fiber adapter is used for connecting the first optical fiber and the second optical fiber, or the optical fiber adapter is used for connecting the second optical fiber and the gain optical fiber.

7. The optical device of claim 6, wherein the optical device is a WDM,

said WDM including a two-wire capillary for introducing two optical fibers into said WDM;

one of the two optical fibers is the first optical fiber or the gain optical fiber;

the other optical fiber of the two optical fibers is the second optical fiber, and the other optical fiber of the two optical fibers is used for: and connecting a pump laser, or inputting an optical signal, or outputting the optical signal amplified by the gain fiber.

8. The optical device according to claim 7,

the two fibers in the twin capillary are not parallel.

9. The light device according to claim 7 or 8,

the WDM includes a first lens for conditioning beams of optical signals in two optical fibers in the two-wire capillary.

10. The optical device according to claim 9,

the curvature radius of the curved surface part of the optical path of the optical signal in the first optical fiber or the gain optical fiber corresponding to the first lens is smaller than that of the curved surface part of the optical path of the optical signal in the second optical fiber corresponding to the first lens; or the like, or, alternatively,

the radial refractive index change of the optical path of the optical signal in the first optical fiber or the gain optical fiber corresponding to the first lens is faster than the radial refractive index change of the optical path of the optical signal in the second optical fiber corresponding to the first lens.

11. The optical device of claim 6, wherein the optical device is an isolator,

the isolator includes a first single wire capillary and a second single wire capillary,

the first single-wire capillary is used for introducing the first optical fiber or the gain optical fiber into the isolator, and the second single-wire capillary is used for introducing the second optical fiber into the isolator.

12. The optical device of claim 11,

the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

13. The optical device according to claim 11 or 12,

the isolator includes a second lens and a third lens,

the second lens is used for adjusting the light beam of the optical signal of the optical fiber in the first single-wire capillary, and the third lens is used for adjusting the light beam of the optical signal of the optical fiber in the second single-wire capillary.

14. The optical device of claim 13,

the focal length of the second lens is smaller than that of the third lens.

15. The optical device of claim 6, wherein the optical device is a fiber optic adapter,

the optical fiber adapter comprises a third single-wire capillary and a fourth single-wire capillary,

the third single-wire capillary is used for introducing the first optical fiber or the gain optical fiber into the optical fiber adapter, and the fourth single-wire capillary is used for introducing the second optical fiber into the optical fiber adapter.

16. The optical device of claim 15,

the optical fiber in the third single-wire capillary and the optical fiber in the fourth single-wire capillary are not parallel.

17. The light device according to claim 15 or 16,

the optical fiber adapter comprises a fourth lens and a fifth lens,

the fourth lens is used for adjusting the light beam of the optical signal of the optical fiber in the third single-wire capillary, and the fifth lens is used for adjusting the light beam of the optical signal of the optical fiber in the fourth single-wire capillary.

18. The optical device of claim 17,

the focal length of the fourth lens is smaller than that of the fifth lens.

19. An optical fiber amplifier comprising a first optical device, a gain fiber, one or more second optical devices, the gain fiber for amplifying an optical signal;

the first optical device is connected with the gain optical fiber by adopting a first optical fiber, or,

the first optical device is directly connected with the gain optical fiber;

the first optical device is connected with the one or more second optical devices by adopting a second optical fiber, and/or inputs an optical signal or outputs an optical signal amplified by the gain optical fiber by adopting the second optical fiber;

wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indices, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

20. The optical fiber amplifier of claim 19, wherein the first optical device is any one or more of the optical devices of claims 1-18.

21. A method of optical device fabrication, comprising:

connecting a first optical fiber with a gain optical fiber, or directly connecting the gain optical fiber, wherein the gain optical fiber is used for amplifying an optical signal;

connecting a second optical fiber with one or more second optical devices, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain optical fiber;

wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indices, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

22. The method of claim 21, wherein the optical device is any one or more of the optical devices of claims 1-18.

23. A method of manufacturing a fiber amplifier comprising a first optical device, a gain fiber, and one or more second optical devices, the gain fiber for amplifying an optical signal, the method comprising:

connecting the first optical device and the gain optical fiber by adopting a first optical fiber, or directly connecting the first optical device and the gain optical fiber;

connecting the first optical device and the one or more second optical devices by using a second optical fiber, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain fiber;

wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indices, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

24. The method of claim 23, wherein the first optical device is the optical device of any one or more of claims 1-18, or wherein the first optical device is an optical device manufactured based on the method of claim 21 or claim 22.

Technical Field

The present application relates to the field of communications, and more particularly, to an optical device constituting an optical fiber amplifier, and a manufacturing method.

Background

In an optical fiber communication network, a gain fiber in a commonly used optical fiber amplifier is a silica glass matrix erbium-doped fiber, and a tail fiber of an optical device such as a Wavelength Division Multiplexer (WDM) and an isolator in the optical fiber amplifier is a silica glass matrix fiber, that is, the two fibers have the same matrix. Because both are silica glass substrate optical fibers, the softening temperature and the refractive index of the two are close, the tail fiber and the gain fiber of the WDM and the isolator are easy to weld, and the welding performance index is good.

In some wide-spectrum fiber amplifiers, other matrix gain fibers may be used in order to increase the gain of the optical signal. For example, some soft glass fibers are used, such as a tellurium-based erbium-doped fiber (erbium-doped in tellurate glass fiber), a fluoride thulium-doped fiber (thulium-doped in fluoride glass fiber), and the like. These gain fibers and silica glass matrix fibers (i.e., pigtails of optical devices) are difficult to fuse and have poor performance indexes, so that the performance of the fiber amplifier is low.

Disclosure of Invention

The application provides an optical device, an optical fiber amplifier and a manufacturing method for forming the optical fiber amplifier, which can design the tail fiber of the optical device according to requirements, thereby improving the application flexibility of the optical fiber amplifier and improving the service performance of the optical fiber amplifier. For example, in some designs, the loss at the optical fiber connection part can be greatly reduced, so that the optical amplifier gain is improved, the noise coefficient is reduced, the processing difficulty is reduced, the cost is reduced, and the performance of the optical fiber amplifier formed by heterogeneous optical fibers is improved.

In a first aspect, a light device is provided. The optical device is applied to an optical fiber amplifier, and adopts a first optical fiber to be connected with a gain optical fiber, wherein the gain optical fiber is used for amplifying an optical signal; the optical device is connected with one or more second optical devices in the optical fiber amplifier by adopting a second optical fiber, and/or an optical signal is input into the optical device by adopting the second optical fiber or an optical signal amplified by the gain optical fiber is output; wherein the first and second optical fibers differ in softening temperature and/or refractive index.

Based on the above technical solution, the refractive index and/or the softening temperature of the optical device applied to the optical fiber amplifier are different between the optical fiber connected to the gain optical fiber and the optical fiber connected to another optical device (for example, the optical device is denoted as a second optical device) or the optical fiber for inputting the optical signal or outputting the optical signal (for example, the optical signal amplified by the gain optical fiber). In one aspect, the optical device may be connected to the gain fiber through a first optical fiber, and the optical device may be connected to another optical device through a second optical fiber, or input an optical signal or output an optical signal amplified by the gain fiber. By the mode, the optical fiber amplifier can be flexibly designed according to requirements, such as tail fibers (namely the first optical fiber and the second optical fiber) of an optical device, so that the use performance of the optical fiber amplifier can be improved. For example, in the case where it is desired to improve the fusion splicing performance between the first optical fiber and the gain optical fiber, the first optical fiber may be designed to be the same as or similar to the gain optical fiber substrate, or the first optical fiber may be designed to be an optical fiber having a smaller difference in softening temperature and/or refractive index from the gain optical fiber, so that the hetero-fiber connection loss can be greatly reduced.

With reference to the first aspect, in certain implementations of the first aspect, an absolute value of a difference in softening temperatures of the first optical fiber and the second optical fiber is greater than an absolute value of a difference in softening temperatures of the first optical fiber and the gain optical fiber; and/or the absolute value of the difference between the refractive indexes of the first optical fiber and the second optical fiber is larger than the absolute value of the difference between the refractive indexes of the first optical fiber and the gain optical fiber.

In one example, the matrix of the first optical fiber is the same as or similar to the matrix of the gain fiber.

Wherein the absolute value of the difference is used to represent the difference. If the absolute value of the difference between the softening temperatures of the first optical fiber and the second optical fiber is greater than the absolute value of the difference between the softening temperatures of the first optical fiber and the gain optical fiber, the difference between the softening temperatures of the first optical fiber and the second optical fiber is greater than the difference between the softening temperatures of the first optical fiber and the gain optical fiber. For another example, the absolute value of the difference between the refractive indexes of the first optical fiber and the second optical fiber is greater than the absolute value of the difference between the refractive indexes of the first optical fiber and the gain optical fiber, that is, the difference between the refractive indexes of the first optical fiber and the second optical fiber is greater than the difference between the refractive indexes of the first optical fiber and the gain optical fiber.

Based on the technical scheme, the absolute value of the difference of the softening temperatures of the first optical fiber and the second optical fiber is larger than the absolute value of the difference of the softening temperatures of the first optical fiber and the gain optical fiber; and/or the absolute value of the difference between the refractive indexes of the first optical fiber and the second optical fiber is larger than the absolute value of the difference between the refractive indexes of the first optical fiber and the gain optical fiber. For example, the optical devices in the fiber amplifier may be connected to the gain fiber using a first fiber that is the same or similar to the gain fiber substrate, and the optical devices may be connected to other optical devices or to input or output optical signals using a second fiber that is different from the gain fiber substrate. That is, the substrate of the fiber to which the gain fiber is connected is the same as or similar to the substrate of the gain fiber. Therefore, the loss at the optical fiber connection can be greatly reduced. In addition, the optical fiber connection loss is reduced, the optical amplifier is beneficial to improving the gain of the optical amplifier, reducing the noise coefficient, reducing the processing difficulty and reducing the cost, and the optical amplifier is expected to become a necessary technology for the optical amplifier of the L/S waveband.

With reference to the first aspect, in certain implementations of the first aspect, the optical device reaches the first optical fiber through at least a section of free space by an optical signal input through the second optical fiber; alternatively, the optical device may be configured to transmit an optical signal input through the first optical fiber to the second optical fiber through at least a free space.

With reference to the first aspect, in certain implementations of the first aspect, the optical device includes at least one capillary for introducing the first optical fiber and/or the second optical fiber stripped of the coating layer into the optical device.

The optical device may comprise at least one optical fibre head for introducing the first and/or second optical fibre stripped of coating into the optical device.

It should be understood that the capillary tubes referred to hereinafter may be replaced with fiber optic heads. The meaning of capillary and fiber tip is understood by those skilled in the art, with the fiber tip being the whole and the capillary being a critical part of the fiber tip.

It is also understood that the optical fiber is introduced into, or otherwise assembled into, the optical device. The transmission direction of the optical signal in the optical fiber is not limited, for example, the introduced optical fiber may be used for inputting the optical signal, outputting the optical signal, and simultaneously inputting and outputting the optical signal.

With reference to the first aspect, in certain implementations of the first aspect, the first optical fiber and the gain fiber are connected by fusion splicing.

With reference to the first aspect, in certain implementations of the first aspect, the light device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter.

In one example, the WDM is configured to feed pump light from a pump laser into the gain fiber.

As yet another example, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

In yet another example, the fiber optic adapter is configured to connect the first optical fiber and the second optical fiber.

With reference to the first aspect, in certain implementations of the first aspect, the optical device is a WDM including a two-wire capillary for introducing two optical fibers into the WDM; one of the two optical fibers is the first optical fiber; the other of the two optical fibers is the second optical fiber, and the other of the two optical fibers is: the gain fiber is used for connecting a pump laser, or inputting an optical signal, or outputting the optical signal amplified by the gain fiber.

Illustratively, the WDM is configured to feed pump light from a pump laser into the gain fiber.

With reference to the first aspect, in certain implementations of the first aspect, the two optical fibers in the two-wire capillary are not parallel.

Illustratively, the two fibers in the twin capillary are not parallel.

With reference to the first aspect, in certain implementations of the first aspect, the WDM includes a first lens to: adjusting the optical beams of the optical signals in the two optical fibers in the two-wire capillary.

With reference to the first aspect, in certain implementations of the first aspect, a radius of curvature of the curved portion of the optical path of the optical signal in the first optical fiber corresponding to the first lens is smaller than a radius of curvature of the curved portion of the optical path of the optical signal in the second optical fiber corresponding to the first lens; or the radial refractive index change of the optical path of the optical signal corresponding to the first lens in the first optical fiber is faster than the radial refractive index change of the optical path of the optical signal corresponding to the second optical fiber in the first lens.

With reference to the first aspect, in certain implementations of the first aspect, the first lens supports a difference in mode spot of the optical signal in the two optical fibers in the two-wire capillary.

With reference to the first aspect, in certain implementations of the first aspect, the mode spots of the optical signals in the two optical fibers in the two-wire capillary are matched.

With reference to the first aspect, in certain implementations of the first aspect, the optical device is an isolator, and the isolator includes a first single-wire capillary and a second single-wire capillary, where the first single-wire capillary is used to introduce the first optical fiber into the isolator, and the second single-wire capillary is used to introduce the second optical fiber into the isolator.

Illustratively, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

With reference to the first aspect, in certain implementations of the first aspect, the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

With reference to the first aspect, in certain implementations of the first aspect, the isolator includes a second lens for adjusting the optical beam of the optical signal of the optical fiber in the first singlet capillary and a third lens for adjusting the optical beam of the optical signal of the optical fiber in the second singlet capillary.

With reference to the first aspect, in certain implementations of the first aspect, a focal length of the second lens is less than a focal length of the third lens.

In combination with the first aspect, in certain implementations of the first aspect, the optical device is an optical fiber adapter, the optical fiber adapter includes a third single-wire capillary and a fourth single-wire capillary, the third single-wire capillary is used to introduce the first optical fiber into the optical fiber adapter, and the fourth single-wire capillary is used to introduce the second optical fiber into the optical fiber adapter.

With reference to the first aspect, in certain implementations of the first aspect, the optical fiber in the third single-wire capillary and the optical fiber in the fourth single-wire capillary are not parallel.

With reference to the first aspect, in certain implementations of the first aspect, the optical fiber adapter includes a fourth lens and a fifth lens, where the fourth lens is configured to adjust a light beam of an optical signal of an optical fiber in the third singlet capillary, and the fifth lens is configured to adjust a light beam of an optical signal of an optical fiber in the fourth singlet capillary.

With reference to the first aspect, in certain implementations of the first aspect, a focal length of the fourth lens is less than a focal length of the fifth lens.

In a second aspect, a light device is provided. The optical device is applied to an optical fiber amplifier, and is directly connected with the gain optical fiber which is used for amplifying optical signals; the optical device is connected with one or more second optical devices in the optical fiber amplifier by adopting a second optical fiber, and/or an optical signal is input into the optical device by adopting the second optical fiber or an optical signal amplified by the gain optical fiber is output; wherein the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

The first optical device is directly connected with the gain optical fiber, namely the tail fiber connected with the gain optical fiber is directly the gain optical fiber, and no fusion point exists between the first optical device and the gain optical fiber.

Based on the above technical solution, the refractive index and/or the softening temperature of the optical device applied to the optical fiber amplifier are different between the gain optical fiber and the optical fiber connected to other optical devices (for example, the gain optical fiber is denoted as a second optical device) or the optical fiber for inputting optical signals or outputting optical signals (for example, optical signals amplified by the gain optical fiber). In one scheme, the optical device may be directly connected to the gain fiber, and the optical device may be connected to another optical device, the input optical signal, or the optical signal amplified by the output gain fiber by using the second optical fiber. By the mode, the heterogeneous optical fiber connection loss can be minimized, the optical amplifier is beneficial to improving the optical amplifier gain, reducing the noise coefficient, reducing the processing difficulty and reducing the cost, and the optical amplifier is expected to become a necessary technology for the optical amplifier of the L/S waveband.

With reference to the second aspect, in certain implementations of the second aspect, the optical device reaches the gain fiber through at least a section of free space through an optical signal input through the second optical fiber; or, the optical device reaches the second optical fiber through at least one section of free space through an optical signal input by the gain optical fiber.

With reference to the second aspect, in certain implementations of the second aspect, the optical device includes at least one capillary for introducing the second optical fiber stripped of the coating layer and/or the gain optical fiber into the optical device.

With reference to the second aspect, in certain implementations of the second aspect, the light device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter.

In one example, the WDM is configured to feed pump light from a pump laser into the gain fiber.

As yet another example, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

In yet another example, the optical fiber adapter is configured to connect the second optical fiber and the gain optical fiber.

With reference to the second aspect, in certain implementations of the second aspect, the optical device is a WDM including a two-wire capillary for introducing two optical fibers into the WDM; one of the two optical fibers is the gain optical fiber; the other of the two optical fibers is the second optical fiber, and the other of the two optical fibers is: the gain fiber is used for connecting a pump laser, or inputting an optical signal, or outputting the optical signal amplified by the gain fiber.

Illustratively, the WDM is configured to feed pump light from a pump laser into the gain fiber.

With reference to the second aspect, in certain implementations of the second aspect, the two optical fibers in the two-wire capillary are not parallel.

With reference to the second aspect, in certain implementations of the second aspect, the WDM includes a first lens to: adjusting the optical beams of the optical signals in the two optical fibers in the two-wire capillary.

With reference to the second aspect, in some implementations of the second aspect, a radius of curvature of the curved portion of the optical path of the optical signal in the gain optical fiber corresponding to the first lens is smaller than a radius of curvature of the curved portion of the optical path of the optical signal in the second optical fiber corresponding to the first lens; or the radial refractive index change of the optical path of the optical signal in the gain optical fiber corresponding to the first lens is faster than the radial refractive index change of the optical path of the optical signal in the second optical fiber corresponding to the first lens.

With reference to the second aspect, in certain implementations of the second aspect, the first lens supports a difference in mode spot of the optical signal in the two optical fibers in the two-wire capillary.

With reference to the second aspect, in certain implementations of the second aspect, the mode spots of the optical signals in the two optical fibers in the two-wire capillary are matched.

With reference to the second aspect, in certain implementations of the second aspect, the optical device is an isolator including a first single-wire capillary and a second single-wire capillary, the first single-wire capillary is used for introducing the gain optical fiber into the isolator, and the second single-wire capillary is used for introducing the second optical fiber into the isolator.

Illustratively, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

With reference to the second aspect, in certain implementations of the second aspect, the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

With reference to the second aspect, in certain implementations of the second aspect, the isolator includes a second lens for adjusting the beam of the optical signal of the optical fiber in the first singlet capillary and a third lens for adjusting the beam of the optical signal of the optical fiber in the second singlet capillary.

With reference to the second aspect, in certain implementations of the second aspect, the focal length of the second lens is less than the focal length of the third lens.

In combination with the second aspect, in certain implementations of the second aspect, the optical device is an optical fiber adapter, the optical fiber adapter includes a third single-wire capillary and a fourth single-wire capillary, the third single-wire capillary is used to introduce the gain optical fiber into the optical fiber adapter, and the fourth single-wire capillary is used to introduce the second optical fiber into the optical fiber adapter.

With reference to the second aspect, in certain implementations of the second aspect, the optical fibers in the third single-wire capillary and the optical fibers in the fourth single-wire capillary are not parallel.

With reference to the second aspect, in certain implementations of the second aspect, the optical fiber adapter includes a fourth lens and a fifth lens, where the fourth lens is configured to adjust a beam of the optical signal of the optical fiber in the third singlet capillary, and the fifth lens is configured to adjust a beam of the optical signal of the optical fiber in the fourth singlet capillary.

With reference to the second aspect, in certain implementations of the second aspect, a focal length of the fourth lens is less than a focal length of the fifth lens.

In a third aspect, a fiber amplifier is provided. The optical fiber amplifier comprises a first optical device, a gain optical fiber and one or more second optical devices, wherein the gain optical fiber is used for amplifying an optical signal; the first optical device is connected with the gain optical fiber by adopting a first optical fiber; the first optical device is connected with the one or more second optical devices by adopting a second optical fiber, and/or inputs an optical signal or outputs an optical signal amplified by the gain optical fiber by adopting the second optical fiber; wherein the first and second optical fibers differ in softening temperature and/or refractive index.

With reference to the third aspect, in some implementations of the third aspect, the first optical device is the optical device described in any one of the possible implementations of the first aspect and the first aspect.

In a fourth aspect, an optical fiber amplifier is provided. The optical fiber amplifier comprises a first optical device, a gain optical fiber and one or more second optical devices, wherein the gain optical fiber is used for amplifying an optical signal; the first optical device is directly connected with the gain optical fiber; the first optical device is connected with the one or more second optical devices by adopting a second optical fiber, and/or inputs an optical signal or outputs an optical signal amplified by the gain optical fiber by adopting the second optical fiber; wherein the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

With reference to the fourth aspect, in some implementations of the fourth aspect, the first optical device is the optical device described in any possible implementation of the second aspect and the second aspect.

In a fifth aspect, a method of fabricating a light device is provided. The method comprises the following steps: connecting a first optical fiber with a gain optical fiber, wherein the gain optical fiber is used for amplifying an optical signal; connecting a second optical fiber with one or more second optical devices, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain optical fiber; wherein the first and second optical fibers differ in softening temperature and/or refractive index.

With reference to the fifth aspect, in certain implementations of the fifth aspect, an absolute value of a difference in softening temperatures of the first optical fiber and the second optical fiber is greater than an absolute value of a difference in softening temperatures of the first optical fiber and the gain optical fiber.

With reference to the fifth aspect, in certain implementations of the fifth aspect, an absolute value of a difference in refractive index of the first optical fiber and the second optical fiber is greater than an absolute value of a difference in refractive index of the first optical fiber and the gain optical fiber.

In one example, the matrix of the first optical fiber is the same as or similar to the matrix of the gain fiber.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical signal input through the second optical fiber reaches the first optical fiber through at least a segment of free space; alternatively, the optical signal input through the first optical fiber reaches the second optical fiber through at least a section of free space.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical device includes at least one capillary through which the first optical fiber and/or the second optical fiber stripped of the coating layer is introduced into the optical device.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the first optical fiber and the gain fiber are connected by fusion splicing.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the light device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter.

In one example, the WDM is configured to feed pump light from a pump laser into the gain fiber.

As yet another example, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

In yet another example, the fiber optic adapter is configured to connect the first optical fiber and the second optical fiber.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical device is a WDM including a two-wire capillary through which two optical fibers are introduced into the WDM; one of the two optical fibers is the first optical fiber; the other of the two optical fibers is the second optical fiber, and the other of the two optical fibers is: the gain fiber is used for connecting a pump laser, or inputting an optical signal, or outputting the optical signal amplified by the gain fiber.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the two optical fibers in the two-wire capillary are not parallel.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the WDM includes a first lens through which beams of optical signals in two optical fibers in the two-wire capillary are adjusted.

With reference to the fifth aspect, in some implementations of the fifth aspect, a radius of curvature of the curved portion of the optical path of the optical signal in the first optical fiber corresponding to the first lens is smaller than a radius of curvature of the curved portion of the optical path of the optical signal in the second optical fiber corresponding to the first lens; or the radial refractive index change of the optical path of the optical signal corresponding to the first lens in the first optical fiber is faster than the radial refractive index change of the optical path of the optical signal corresponding to the second optical fiber in the first lens.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the first lens supports a difference in mode spot of the optical signal in the two optical fibers in the two-wire capillary.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the mode spots of the optical signals in the two optical fibers in the two-wire capillary are matched.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical device is an isolator that includes a first single-wire capillary and a second single-wire capillary, the first optical fiber is introduced into the isolator through the first single-wire capillary, and the second optical fiber is introduced into the isolator through the second single-wire capillary.

Illustratively, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the isolator includes a second lens through which the beam of the optical signal of the optical fiber in the first singlet capillary is adjusted and a third lens through which the beam of the optical signal of the optical fiber in the second singlet capillary is adjusted.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the focal length of the second lens is less than the focal length of the third lens.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the optical device is an optical fiber adapter, the optical fiber adapter includes a third single-wire capillary and a fourth single-wire capillary, the third single-wire capillary introduces the first optical fiber into the optical fiber adapter, and the fourth single-wire capillary introduces the second optical fiber into the optical fiber adapter.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical fibers in the third single-wire capillary and the optical fibers in the fourth single-wire capillary are not parallel.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the optical fiber adapter includes a fourth lens and a fifth lens, and the fourth lens adjusts the optical beam of the optical signal of the optical fiber in the third singlet capillary, and the fifth lens adjusts the optical beam of the optical signal of the optical fiber in the fourth singlet capillary.

With reference to the fifth aspect, in certain implementations of the fifth aspect, a focal length of the fourth lens is less than a focal length of the fifth lens.

In a sixth aspect, a method of fabricating a light device is provided. The method comprises the following steps: directly connecting the gain optical fiber, wherein the gain optical fiber is used for amplifying optical signals; connecting a second optical fiber with one or more second optical devices in the optical fiber amplifier, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain optical fiber; wherein the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

With reference to the sixth aspect, in certain implementations of the sixth aspect, an optical signal input through the second optical fiber reaches the gain fiber through at least a segment of free space; alternatively, the optical signal input through the gain fiber reaches the second fiber through at least a section of free space.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the optical device includes at least one capillary through which the second optical fiber stripped of the coating layer and/or the gain optical fiber is introduced into the optical device.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the light device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter.

In one example, the WDM is configured to feed pump light from a pump laser into the gain fiber.

As yet another example, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

In yet another example, the optical fiber adapter is configured to connect the second optical fiber and the gain optical fiber.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the optical device is a WDM including a two-wire capillary through which two optical fibers are introduced into the WDM; one of the two optical fibers is the gain optical fiber; the other of the two optical fibers is the second optical fiber, and the other of the two optical fibers is: the gain fiber is used for connecting a pump laser, or inputting an optical signal, or outputting the optical signal amplified by the gain fiber.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the two optical fibers in the two-wire capillary are not parallel.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the WDM includes a first lens through which beams of optical signals in two optical fibers in the two-wire capillary are adjusted.

With reference to the sixth aspect, in some implementations of the sixth aspect, a radius of curvature of the curved portion of the optical path of the optical signal in the gain fiber corresponding to the first lens is smaller than a radius of curvature of the curved portion of the optical path of the optical signal in the second fiber corresponding to the first lens; or the radial refractive index change of the optical path of the optical signal in the gain optical fiber corresponding to the first lens is faster than the radial refractive index change of the optical path of the optical signal in the second optical fiber corresponding to the first lens.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the first lens supports a difference in mode spot of the optical signal in the two optical fibers in the two-wire capillary.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the mode spots of the optical signals in the two optical fibers in the two-wire capillary are matched.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the optical device is an isolator that includes a first single-wire capillary and a second single-wire capillary, the gain optical fiber is introduced into the isolator through the first single-wire capillary, and the second optical fiber is introduced into the isolator through the second single-wire capillary.

Illustratively, the isolator is configured to pass or lose less optical signals transmitted in one direction and not pass or lose more optical signals transmitted in the opposite direction.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the isolator includes a second lens through which the beam of the optical signal of the optical fiber in the first singlet capillary is adjusted and a third lens through which the beam of the optical signal of the optical fiber in the second singlet capillary is adjusted.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the focal length of the second lens is less than the focal length of the third lens.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the optical device is an optical fiber adapter, the optical fiber adapter includes a third single-wire capillary and a fourth single-wire capillary, the third single-wire capillary introduces the gain optical fiber into the optical fiber adapter, and the fourth single-wire capillary introduces the second optical fiber into the optical fiber adapter.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the optical fibers in the third single-wire capillary and the optical fibers in the fourth single-wire capillary are not parallel.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the optical fiber adapter includes a fourth lens and a fifth lens, the fourth lens adjusts the optical beam of the optical signal of the optical fiber in the third singlet capillary, and the fifth lens adjusts the optical beam of the optical signal of the optical fiber in the fourth singlet capillary.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the focal length of the fourth lens is less than the focal length of the fifth lens.

In a seventh aspect, a method of manufacturing an optical fiber amplifier is provided. The optical fiber amplifier comprises a first optical device, a gain optical fiber and one or more second optical devices, wherein the gain optical fiber is used for amplifying an optical signal, and the method comprises the following steps: connecting the first optical device and the gain optical fiber by adopting a first optical fiber; connecting the first optical device and the one or more second optical devices by using a second optical fiber, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain fiber; wherein the first and second optical fibers differ in softening temperature and/or refractive index.

With reference to the seventh aspect, in some implementations of the seventh aspect, the first optical device is the optical device described in any one of the first aspect and the first possible implementation, or the first optical device is an optical device manufactured based on the method described in any one of the fifth aspect and the fifth possible implementation.

In an eighth aspect, a method of manufacturing an optical fiber amplifier is provided. The optical fiber amplifier comprises a first optical device, a gain optical fiber and one or more second optical devices, wherein the gain optical fiber is used for amplifying an optical signal, and the method comprises the following steps: directly connecting the first optical device and the gain fiber; connecting the first optical device and the one or more second optical devices by using a second optical fiber, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain fiber; wherein the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

With reference to the eighth aspect, in some implementations of the eighth aspect, the first optical device is the optical device described in any one of the second aspect and the second possible implementation, or the first optical device is an optical device manufactured based on the method described in any one of the sixth aspect and the sixth possible implementation.

In a ninth aspect, a method of wavelength division multiplexer WDM fabrication is provided. The WDM is applied to an optical fiber amplifier, the WDM includes a two-wire capillary, the method includes: introducing two optical fibers into the WDM through the bifilar capillary, one of the two optical fibers being a first optical fiber or a gain fiber, the other of the two optical fibers being a second optical fiber, the other of the two optical fibers being: the optical fiber is used for connecting a pump laser, or inputting an optical signal, or outputting an optical signal amplified by the gain fiber, wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indexes, or the second optical fiber and the gain fiber have different softening temperatures and/or refractive indexes.

With reference to the ninth aspect, in certain implementations of the ninth aspect, the WDM is the WDM of any one of the first to eighth aspects described above.

In a tenth aspect, a method of fabricating a separator is provided. The isolator is applied to an optical fiber amplifier, the isolator comprises a first single-wire capillary and a second single-wire capillary, and the method comprises the following steps: introducing a first optical fiber or gain fiber into the isolator through the first single wire capillary; introducing a second optical fiber into said isolator through said second single wire capillary; wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indices, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

With reference to the tenth aspect, in certain implementations of the tenth aspect, the separator is the separator of any one of the first to eighth aspects described above.

In an eleventh aspect, a method of manufacturing a fiber optic adapter is provided. The optical fiber adapter is applied to an optical fiber amplifier, the optical fiber adapter comprises a third single-wire capillary and a fourth single-wire capillary, and the method comprises the following steps: introducing a first optical fiber or a gain optical fiber into the optical fiber adapter through the third single-wire capillary; introducing a second optical fiber into the optical fiber adapter through the fourth single-wire capillary; wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indices, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indices.

With reference to the eleventh aspect, in certain implementations of the eleventh aspect, the optical fiber adapter is the optical fiber adapter of any one of the first to eighth aspects.

In a twelfth aspect, a lens is provided. The light path through the lens comprises a first light path and a second light path; the curvature radius of the curved surface part of the lens corresponding to the first optical path is smaller than that of the curved surface part of the lens corresponding to the second optical path; or the radial refractive index change of the lens corresponding to the first optical path is faster than the radial refractive index change of the lens corresponding to the second optical path.

With reference to the twelfth aspect, in certain implementations of the twelfth aspect, the lens is the first lens described in the first aspect or the second aspect and any possible implementation of the first aspect or the second aspect.

Drawings

Fig. 1 is a schematic diagram of an application scenario applicable to the embodiment of the present application.

Fig. 2 shows a schematic block diagram of an optical fiber amplifier suitable for use in embodiments of the present application.

FIG. 3 shows a schematic diagram of the refraction of a hetero-fiber with different refractive indices.

Fig. 4 is a schematic diagram of an optical fiber amplifier provided according to an embodiment of the present application.

Fig. 5 shows a schematic diagram of a fiber amplifier suitable for use in an embodiment of the present application.

Fig. 6 shows a schematic diagram of a fiber amplifier suitable for use in yet another embodiment of the present application.

Fig. 7 shows a schematic diagram of a fiber amplifier suitable for use in another embodiment of the present application.

Fig. 8 shows a schematic diagram of a fiber amplifier suitable for use in yet another embodiment of the present application.

Fig. 9 shows a schematic diagram of a WDM suitable for use in embodiments of the present application.

FIG. 10 shows a schematic diagram of a patch for spatial type WDM suitable for use in embodiments of the present application.

FIG. 11 shows a schematic diagram of adjusting the angle between two optical fibers in a two-wire capillary suitable for use in embodiments of the present application.

Fig. 12 to 13 show schematic views of lenses suitable for use in embodiments of the present application.

FIG. 14 shows a schematic view of a separator suitable for use in embodiments of the present application.

Figure 15 is a schematic diagram of a fiber optic adapter suitable for use with embodiments of the present application.

Fig. 16 is a schematic diagram of a method of manufacturing a light device according to an embodiment of the present application.

Fig. 17 is a schematic diagram of a method of manufacturing a light device according to yet another embodiment of the present application.

Fig. 18 is a schematic diagram of a method of manufacturing an optical fiber amplifier according to an embodiment of the present application.

Fig. 19 is a schematic diagram of a method of manufacturing an optical fiber amplifier according to yet another embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical scheme of the embodiment of the application can be applied to an optical fiber communication network, for example, the technical scheme of the embodiment of the application can be applied to an optical fiber amplifier in the optical fiber communication network, and the optical fiber amplifier is mainly located at an optical amplifier station and an optical amplifier network element in the optical fiber communication network. The technical scheme of the embodiment of the application can be used for realizing the optical fiber amplifier composed of heterogeneous optical fibers and also can be used for realizing the optical fiber amplifier composed of optical fibers with different mode spots (including different mode spot diameters and/or different numerical apertures). A scenario applicable to the embodiment of the present application is described in detail below with reference to fig. 1.

Fig. 1 is a schematic diagram of an application scenario applicable to the embodiment of the present application. In a fiber optic communications network, an optical transmitter, an optical receiver, and one or more fiber amplifiers may be included. As shown in fig. 1, an optical fiber amplifier is mainly located in the middle of an optical fiber line (or line fiber) in an optical fiber communication network, and is used for amplifying an optical signal and extending an optical signal transmission distance.

It should be understood that fig. 1 is merely an exemplary illustration and the present application is not limited thereto. For example, more optical devices may be included in a fiber optic communications network; as another example, embodiments of the present application may also be applied in any scenario involving fiber amplifiers.

For the understanding of the embodiments of the present application, first, a brief description of the optical fiber amplifier will be given with reference to fig. 2.

As shown in fig. 2, the fiber amplifier may include, for example, but is not limited to: a pump laser, a Wavelength Division Multiplexer (WDM), an isolator, and a gain fiber. In which a pump laser generates pump light, WDM can combine an input optical signal (or input signal light) and the pump light to feed the gain fiber. The gain fiber may be a fiber in which a gain medium is doped. In the gain optical fiber, the pump light excites the gain medium ions in the gain optical fiber to a high energy level, and after the input optical signal is input, the gain medium ions in the gain optical fiber are subjected to stimulated radiation when the gain medium ions are transited from the high energy level to a low energy level, so that the input optical signal is amplified, and the output optical signal is obtained.

In the optical fiber amplifier, the mode of optical fiber fusion is generally adopted between the gain optical fiber and the WDM and between the gain optical fiber and the isolator, so that the loss can be reduced, and the noise coefficient can be reduced. As shown in fig. 2, the pigtail of the WDM is fusion spliced with the gain fiber, and the pigtail of the isolator is fusion spliced with the gain fiber.

In an optical fiber communication network, a gain fiber in a commonly used optical fiber amplifier is a silica glass substrate erbium-doped fiber, and tail fibers of optical devices such as WDM and an isolator are silica glass substrate fibers, namely, the two substrates are the same. Because both are quartz glass substrate optical fibers, the softening temperature and the refractive index of the two are basically consistent, the tail fiber and the gain fiber of the WDM and the isolator are easy to weld, and the welding performance index is good. For example, when the pigtail and the gain fiber of the WDM and isolator are fusion spliced, the insertion loss (i.e., insertion loss) can be less than 0.1dB (decibel, dB), and the return loss (i.e., return loss) can be less than (-40 dB).

In some wide-spectrum fiber amplifiers, other matrix gain fibers may be used in order to increase the gain of the optical signal. For example, some soft glass fibers are used, such as a tellurium-based erbium-doped fiber (erbium-doped in tellurate glass fiber), a fluoride thulium-doped fiber (thulium-doped in fluoride glass fiber), and the like. The gain fibers and the quartz glass substrate fibers are difficult to weld and have poor performance indexes.

The example is that the gain fiber adopts soft glass fiber, and the tail fiber of optical devices such as WDM and isolator adopts quartz glass substrate fiber. The softening temperature of the soft glass optical fiber is different from that of the quartz glass substrate optical fiber, so that the soft glass optical fiber is softened during welding, the quartz glass substrate optical fiber cannot be welded, the welding position of the soft glass optical fiber is deformed, the welding loss is increased, and 1-3 dB can be achieved generally. In addition, soft glass fibers also typically have a different index of refraction than silica glass matrix fibers. For example, a silica glass matrix fiber may have a refractive index of about 1.47, while a soft glass fiber may have a refractive index of about 2.0. The two optical fibers are directly welded with strong reflection by flat cutting, and generally need to be welded by oblique cutting. However, in the case of oblique-angle fusion, since the refractive indexes of the soft glass fiber and the silica glass matrix fiber are different, refraction occurs on the fusion inclined plane, the mismatch of the mode spots of the two fibers is more serious, and the insertion loss is increased, as shown in fig. 3. Meanwhile, the quartz glass substrate optical fiber is not softened, but the soft glass optical fiber is softened, so that the longitudinal displacement of the fiber cores of the two optical fibers is more easily caused, and the welding loss is further increased.

In view of the above, the present application provides a low-cost, high-performance optical fiber amplifier made of heterogeneous optical fibers. For example, when a gain fiber having a softening temperature or refractive index different from that of the silica glass substrate fiber is used, the optical fiber amplifier can be constructed by butting the gain fiber and the silica glass substrate fiber.

Various embodiments provided herein will be described in detail below with reference to the accompanying drawings.

Fig. 4 is a schematic diagram of a proposed fiber amplifier according to an embodiment of the present application.

The fiber amplifier may include a first optical device, one or more second optical devices, and a gain fiber. It will be appreciated that gain fibers may be used to amplify optical signals.

The first optical device is connected with the gain optical fiber and adopts a first optical fiber to connect the gain optical fiber or directly connect the gain optical fiber;

the first optical device is connected with one or more second optical devices by adopting a second optical fiber, and/or inputs/outputs an optical signal by adopting the second optical fiber (namely, the optical signal is input by adopting the second optical fiber or the optical signal amplified by the output gain optical fiber);

wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indexes, or the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indexes.

In the embodiment of the present application, the first optical device is connected to the gain fiber, and at least includes the following two schemes:

scheme 1: the first optical device is connected to the gain fiber using a first optical fiber, as shown in (1) of fig. 4. The first and second optical fibers differ in softening temperature and/or refractive index.

Scheme 2: the first optical device is directly connected to the gain fiber as shown in (2) of fig. 4. The second fiber and the gain fiber have different softening temperatures and/or refractive indices. The first optical device is directly connected with the gain optical fiber, that is, the pigtail of the first optical device connected with the gain optical fiber is the gain optical fiber, and there is no fusion point between the first optical device and the gain optical fiber.

Both schemes are described in detail below.

The optical fiber amplifier composed of the heterogeneous optical fibers provided by the embodiment of the application is simply marked as a heterogeneous optical fiber amplifier, and optical fibers of optical devices forming the heterogeneous optical fiber amplifier, which are connected with other optical devices, are different from optical fibers connected with gain optical fibers, so that the flexibility is higher and the performance is higher. In the above scheme 1, the first optical device in the hetero fiber amplifier is connected to the gain fiber using the first optical fiber; the first optical device in the heterogeneous optical fiber amplifier is connected with other optical devices by using a second optical fiber, and inputs optical signals or outputs optical signals. In the above scheme 2, the first optical device in the heterogeneous optical fiber amplifier is directly connected to the gain optical fiber, that is, the pigtail connecting the first optical device and the gain optical fiber is the gain optical fiber, and there is no fusion point between the first optical device and the gain optical fiber; the first optical device in the heterogeneous optical fiber amplifier uses the second optical fiber to be connected with other optical devices, and inputs optical signals or outputs optical signals. By the mode, the optical fiber amplifier can be flexibly designed and used according to requirements, and the use performance of the optical fiber amplifier is improved. For example, in the above-described embodiment 1, in the case where it is necessary to improve the fusion splicing performance between the first optical fiber and the gain fiber, the first optical fiber may be designed to be an optical fiber having the same or similar matrix as the gain fiber, or may be designed to be an optical fiber having a smaller difference in softening temperature and/or refractive index from the gain fiber.

One specific example is that the first optical fiber uses a passive fiber that is the same as or similar to the gain fiber substrate, i.e., a fiber without a gain medium doped therein, or the first optical fiber directly uses a gain fiber.

For example, based on the above scheme 1, in one possible implementation manner, the first optical fiber and the gain optical fiber are connected by fusion splicing, that is, there is a fusion splice between the first optical fiber and the gain optical fiber. In the actual design of the optical fiber amplifier, the uniformity of the gain fibers of different batches may vary, so that the length of the gain fiber may need to be adjusted. Therefore, the first optical fiber and the gain optical fiber are connected in a fusion mode, and the length of the gain optical fiber can be conveniently adjusted. Meanwhile, as the first optical fiber adopts the optical fiber which is the same as or similar to the gain optical fiber substrate, or the first optical fiber is the optical fiber with smaller difference with the softening temperature and/or refractive index of the gain optical fiber, the performance indexes of fusion welding loss and return loss between the first optical fiber and the gain optical fiber are better.

For another example, based on the above scheme 2, it may be designed that the first optical device is directly connected to the gain fiber, that is, the pigtail connected to the gain fiber is directly the gain fiber, and there is no fusion point between the first optical device and the gain fiber. In the above scheme 2, in a possible implementation manner, the gain fiber is directly connected to or assembled into the first optical device. Since the first optical device and the gain fiber do not need to be welded and have no welding point, compared with the above scheme 1, the loss of the heterogeneous fiber connection can be further reduced, and the performance (such as the performance of gain and noise coefficient) of the heterogeneous fiber amplifier can be improved. In general, in the above solution 2, the first optical device and the gain fiber are connected into a whole, and it is not easy to adjust the length of the gain fiber, so the solution 2 is suitable for being implemented under the condition that the uniformity of the gain fiber is relatively good, that is, the requirement of the solution 2 on the uniformity of the gain fiber is relatively high.

It should be understood that the first optical fiber and the second optical fiber are only named for differentiation, and the naming does not limit the scope of the embodiments of the present application.

Optionally, the difference in softening temperatures of the first and second optical fibers is greater than the difference in softening temperatures of the first and gain optical fibers; and/or the difference in refractive index between the first optical fiber and the second optical fiber is greater than the difference in refractive index between the first optical fiber and the gain optical fiber. Such differences include absolute values of the differences, relative values of the absolute values of the differences, and so forth. For example, the absolute value of the difference in the softening temperatures of the first and second optical fibers is greater than the absolute value of the difference in the softening temperatures of the second and gain optical fibers; and/or the absolute value of the difference between the refractive indexes of the first optical fiber and the second optical fiber is larger than the absolute value of the difference between the refractive indexes of the first optical fiber and the gain optical fiber. Regarding the differences, no further description is given below.

In one example, the matrix of the first optical fiber is the same as or close to the matrix of the gain fiber. For example, the softening temperature of the optical fiber connected to the gain fiber by the first optical device is the same as or close to the softening temperature of the gain fiber, and the absolute value of the difference between the softening temperatures of the first optical fiber and the second optical fiber is greater than the absolute value of the difference between the softening temperatures of the first optical fiber and the gain fiber, that is, the softening temperature of the second optical fiber is significantly different from the softening temperatures of the first optical fiber and the gain fiber.

In another example, the refractive index of the first optical fiber is the same as or close to the refractive index of the gain fiber. For example, the absolute value of the difference in refractive index between the first and second optical fibers is greater than the absolute value of the difference in refractive index between the first and gain optical fibers. In this example, the matrix of any two of the first optical fiber, the second optical fiber, and the gain fiber may be the same or different.

It should be understood that in scheme 1, any first optical fiber satisfying the following conditions is applicable to the present embodiment: the difference in softening temperature or the difference in refractive index between the second optical fiber and the first optical fiber is larger than the difference in softening temperature or the difference in refractive index between the first optical fiber and the gain optical fiber.

With respect to the specific forms of the first optical fiber, the gain optical fiber and the second optical fiber, the embodiments of the present invention are not limited, and two types of optical fibers with different matrixes, such as two types of optical fibers with different softening temperatures or two types of optical fibers with different refractive indexes, are all suitable for the embodiments of the present invention.

In one possible design, the second fiber may be a silica glass matrix fiber, and the first fiber or the gain fiber is a fiber of other matrix than the silica glass matrix fiber.

In yet another possible design, the first optical fiber or the gain optical fiber may be a soft glass optical fiber, such as a tellurium-based erbium-doped fiber (erbium-doped in tellurate glass fiber), a fluoride thulium-doped fiber (thulium-doped in fluoride glass fiber), or the like, or the first optical fiber or the gain optical fiber may be an optical fiber with other matrix different from that of the second optical fiber, without limitation.

For example, the first optical fiber in the following embodiments may be replaced with a soft glass optical fiber, and the second optical fiber may be replaced with a silica glass matrix optical fiber.

The first optical device represents an optical device in an optical fiber amplifier.

Optionally, the first optical device may be one or more of a WDM, an isolator, a fiber optic adapter.

In one possible design, the first optical device is a WDM.

With scheme 1, as shown in fig. 5, the optical fiber in which the WDM is connected to the gain fiber is a first optical fiber, and the optical fiber in which the WDM is connected to the pump laser and the optical fiber for inputting the optical signal is a second optical fiber. The difference of the softening temperatures of the first optical fiber and the second optical fiber is larger than that of the first optical fiber and the gain optical fiber; and/or the difference in refractive index between the first optical fiber and the second optical fiber is greater than the difference in refractive index between the first optical fiber and the gain optical fiber. In one example, the substrate of the first optical fiber and the substrate of the gain optical fiber are the same or close, i.e., the substrate of the optical fiber to which the WDM is connected and the substrate of the gain optical fiber are the same or close. As yet another example, the glass structure of the first optical fiber and the gain fiber are the same or close, i.e., the glass structure of the optical fiber to which the WDM is connected and the gain fiber are the same or close. In another example, the first optical fiber and the gain optical fiber are connected by fusion splicing, that is, a fusion splice exists between the first optical fiber and the gain optical fiber.

With scheme 2, the WDM is directly connected to the gain fiber as shown in fig. 6. In other words, the gain fiber is introduced or assembled directly into the WDM without a fusion splice between the WDM and the gain fiber. The optical fiber in which the WDM is connected to the pump laser and the optical fiber of the input optical signal is the second optical fiber.

In yet another possible design, the first optical device is an isolator.

With the scheme 1, as shown in fig. 5, the optical fiber in which the isolator is connected to the gain optical fiber is a first optical fiber, and the optical fiber in which the isolator is connected to the optical fiber outputting the optical signal (i.e., the optical signal amplified by the gain optical fiber) is a second optical fiber. The absolute value of the difference between the softening temperatures of the first optical fiber and the second optical fiber is greater than the absolute value of the difference between the softening temperatures of the first optical fiber and the gain optical fiber; and/or the absolute value of the difference between the refractive indexes of the first optical fiber and the second optical fiber is larger than the absolute value of the difference between the refractive indexes of the first optical fiber and the gain optical fiber. In one example, the matrix of the first optical fiber and the matrix of the gain fiber are the same or close, i.e., the matrix of the fiber to which the isolator is connected and the matrix of the gain fiber are the same or close. As yet another example, the glass structure of the first optical fiber and the gain fiber are the same or close, i.e., the glass structure of the optical fiber to which the WDM is connected and the gain fiber are the same or close. In another example, the first optical fiber and the gain optical fiber are connected by fusion splicing, that is, a fusion splice exists between the first optical fiber and the gain optical fiber.

With scheme 2, the isolator is directly connected to the gain fiber as shown in fig. 6. In other words, the gain fiber is directly introduced into the isolator or the gain fiber is directly fitted into the isolator without a fusion-splice between the isolator and the gain fiber. The optical fiber of the isolator connected to the optical fiber outputting the optical signal is the second optical fiber.

In yet another possible design, the first optical device is a fiber optic adapter.

With the scheme 1, as shown in fig. 7, an optical fiber connected to the optical fiber adapter (e.g., adapter 1 and/or adapter 2) and the gain optical fiber is a first optical fiber, and an optical fiber connected to the optical fiber adapter and the isolator or the WDM is a second optical fiber. The difference of the softening temperatures of the first optical fiber and the second optical fiber is larger than that of the first optical fiber and the gain optical fiber; and/or the difference in refractive index between the first optical fiber and the second optical fiber is greater than the difference in refractive index between the first optical fiber and the gain optical fiber. In one example, the substrate of the first optical fiber and the substrate of the gain optical fiber are the same or close, that is, the substrate of the optical fiber connected to the gain optical fiber and the substrate of the gain optical fiber at the optical fiber adapter are the same or close. As yet another example, the glass structure of the first optical fiber and the gain fiber are the same or close, i.e., the glass structure of the optical fiber to which the WDM is connected and the gain fiber are the same or close. In another example, the first optical fiber and the gain optical fiber are connected by fusion splicing, that is, a fusion splice exists between the first optical fiber and the gain optical fiber.

With the scheme 2, as shown in fig. 8, the optical fiber adapter (e.g., adapter 1 and adapter 2) is directly connected to the gain optical fiber. In other words, the gain fiber is introduced directly into the fiber optic adapter, or the gain fiber is assembled directly into the fiber optic adapter, with no fusion splice between the fiber optic adapter and the gain fiber. And the optical fiber connected with the isolator and the WDM by the optical fiber adapter is a second optical fiber.

It should be understood that fig. 5 to 8 are exemplary illustrations, and the embodiments of the present application are not limited thereto. For example, the number of the optical fiber adapters is not limited in the embodiments of the present application. For example, fig. 7 or 8 may also include a fiber adapter, such as adapter 1 or adapter 2 only. As another example, the embodiments of the present application do not limit the form and number of the improved optical devices. For example, in fig. 5, only the optical fiber having the WDM or the isolator connected to the gain fiber may be the first optical fiber. As another example, in fig. 6, only the optical fiber to which the WDM or the isolator is connected may be the gain fiber.

The two schemes described above, scheme 1 and scheme 2, are described in detail below.

Scheme 1: the first optical device is connected with the gain optical fiber by adopting a first optical fiber.

Optionally, the first optical fiber and the gain optical fiber are connected by fusion splicing.

The first optical device is connected with the gain optical fiber by adopting a first optical fiber, namely, the first optical device is connected with the tail fiber of the gain optical fiber and is the first optical fiber. In one possible implementation, the first optical device comprises at least one capillary (or fiber head) for introducing or fitting the first optical fiber stripped of the coating into the first optical device.

The first optical device connects one or more of the following with a second optical fiber: other optical devices (i.e., one or more second optical devices), an input optical signal, an output optical signal (e.g., an optical signal amplified by a gain fiber). In one possible implementation, the first optical device includes at least one capillary for introducing or fitting the second optical fiber stripped of the coating into the first optical device.

It should be understood that the first optical device includes at least one capillary, the at least one capillary is used for introducing the first optical fiber with the coating layer removed into the first optical device, and does not limit the transmission direction of the optical signal in the first optical fiber, and the first optical fiber can be used for inputting the optical signal, outputting the optical signal, and inputting and outputting the optical signal at the same time; similarly, the first optical device includes at least one capillary, the at least one capillary is used for introducing the second optical fiber with the coating layer stripped into the first optical device, and the transmission direction of the optical signal in the second optical fiber is not limited, and the second optical fiber can be used for outputting the optical signal, and inputting and outputting the optical signal simultaneously.

It is also understood that the introduction of the first optical fiber into the capillary of the first optical device, and the introduction of the second optical fiber into the capillary of the first optical device, may be the same capillary, such as by introducing the first optical fiber and the second optical fiber into the first optical device through a two-wire capillary (alternatively referred to as a two-wire fiber capillary, alternatively referred to as a two-wire fiber stub); it is also possible to introduce the first optical fiber and the second optical fiber into the first optical device via different capillaries, e.g. via two single-wire capillaries (alternatively referred to as single-wire fiber capillaries, alternatively referred to as single-wire fiber tips), respectively.

The difference in softening temperature or the difference in refractive index between the second optical fiber and the first optical fiber is larger than the difference in softening temperature or the difference in refractive index between the first optical fiber and the gain optical fiber. In other words, the difference in softening temperature or the difference in refractive index between the optical fiber connected to the first optical device and the optical fiber connected to the gain optical fiber is larger than the difference in softening temperature or the difference in refractive index between the optical fiber connected to the gain optical fiber and the optical fiber connected to the first optical device.

The first optical device uses the optical signal input by the second optical fiber to reach the first optical fiber at least through a section of free space, or the first optical device uses the optical signal input by the first optical fiber to reach the second optical fiber at least through a section of free space. That is, the optical signal transmitted in the optical fiber in which the first optical device is connected to another optical device or the input optical signal is connected to the optical fiber in which the first optical device is connected to the gain fiber (i.e., the first optical fiber) through at least a space, or the optical signal transmitted in the optical fiber in which the first optical device is connected to the gain fiber is connected to the optical device in which the optical signal transmitted in the optical fiber in which the first optical device is connected to another optical device or the output optical signal is connected to the optical device (i.e., the second optical fiber) through at least a space.

Take WDM or isolator as an example. One possible design is to replace the fiber pigtail, where the WDM or isolator is connected to the gain fiber, with the first fiber (e.g. the same or close to the gain fiber substrate) to form a fiber amplifier consisting of a heterogeneous fiber.

Example 1, as shown in fig. 5, a fiber amplifier may be composed of WDM, pump laser, isolator, and gain fiber. The existing heterogeneous optical fiber amplifier is improved to obtain the improved heterogeneous optical fiber amplifier.

For example, the first optical fiber may be the same or similar to the matrix of the gain fiber. For example, the fiber pigtail connecting the WDM and/or isolator to the gain fiber can be replaced with the first fiber. The optical fiber in which the WDM is connected to the pump laser and the optical fiber in which the optical signal is input, and the optical fiber in which the isolator outputs the optical signal (i.e., the optical signal amplified by the gain fiber) remain the second optical fiber.

As another example, the difference in softening temperature or refractive index between the optical fiber in which the WDM is introducing the input optical signal (i.e., the second optical fiber) and the optical fiber in which the WDM is connected to the gain optical fiber (i.e., the first optical fiber) is larger than the difference in softening temperature or refractive index between the optical fiber in which the WDM is connected to the gain optical fiber and the gain optical fiber.

As another example, the difference in softening temperature or refractive index between the optical fiber of the WDM-connected pump laser (i.e., the second optical fiber) and the optical fiber of the WDM-connected gain optical fiber is larger than the difference in softening temperature or refractive index between the optical fiber of the WDM-connected gain optical fiber and the gain optical fiber.

For another example, the difference between the softening temperatures of the optical fiber (i.e., the second optical fiber) for outputting the optical signal by the isolator and the optical fiber (i.e., the first optical fiber) for connecting the gain optical fiber by the isolator is greater than the difference between the softening temperatures of the optical fiber for connecting the gain optical fiber by the isolator and the gain optical fiber.

The WDM shown in fig. 5, reference may be made to the WDM shown in fig. 9 below; and/or the isolator shown in fig. 5, may be referred to as the isolator shown in fig. 14, infra.

Example 2, as shown in fig. 7, a fiber amplifier may be comprised of a WDM, a pump laser, an isolator, one or more fiber splices, and a gain fiber. In this example, one or more fiber adapters, such as adapter 1 and adapter 2, may be added. In particular, the fiber pigtails connecting the adapter 1 and adapter 2 to the gain fiber may be replaced by first fibers (e.g., fibers that are the same or close to the gain fiber matrix). And the optical fiber connected with the WDM by the adapter 1 and the optical fiber connected with the isolator by the adapter 2 are both second optical fibers.

For example, the first fiber is the same or close to the matrix of the gain fiber. For example, the optical fiber pigtail connecting the adapter 1 and/or the adapter 2 with the gain optical fiber can be replaced by the first optical fiber. The optical fiber of the adapter 1 connected to the WDM and the optical fiber of the adapter 2 connected to the isolator remain the second optical fiber.

For another example, the softening temperature difference between the optical fiber (i.e., the second optical fiber) connected to the WDM by the adapter 1 and the optical fiber (i.e., the first optical fiber) connected to the gain optical fiber by the adapter 1 is greater than the softening temperature difference between the optical fiber connected to the gain optical fiber by the adapter 1 and the gain optical fiber.

For another example, the softening temperature difference between the optical fiber of the isolator connected by the adapter 2 and the optical fiber of the gain optical fiber connected by the adapter 2 is greater than the softening temperature difference between the optical fiber of the gain optical fiber connected by the adapter 2 and the gain optical fiber.

Both the existing WDM and isolator can be adapted to the fiber amplifier shown in fig. 7.

Scheme 2: the first optical device is directly connected with the gain optical fiber, and no welding point exists between the first optical device and the gain optical fiber.

The first optical device is directly connected with the gain optical fiber, namely, the first optical device is connected with the tail fiber of the gain optical fiber and directly serves as the gain optical fiber, and therefore, no fusion point exists between the first optical device and the gain optical fiber. In one possible implementation, the first optical device comprises at least one capillary (or fiber head) for introducing or fitting the gain fiber stripped of the coating into the first optical device.

The first optical device connects one or more of the following with a second optical fiber: other optical devices (e.g., denoted as second optical devices), input optical signals, and output optical signals (e.g., optical signals amplified by gain fibers). In one possible implementation, the first optical device includes at least one capillary for introducing or fitting the second optical fiber stripped of the coating into the first optical device.

It should be understood that the first optical device includes at least one capillary, the at least one capillary is used for introducing the gain fiber with the coating layer removed into the first optical device, and the transmission direction of the optical signal in the gain fiber is not limited, and the gain fiber can be used for inputting the optical signal, outputting the optical signal, and inputting and outputting the optical signal at the same time; similarly, the first optical device includes at least one capillary, the at least one capillary is used for introducing the second optical fiber with the coating layer stripped into the first optical device, and the transmission direction of the optical signal in the second optical fiber is not limited, and the second optical fiber can be used for outputting the optical signal, and inputting and outputting the optical signal simultaneously.

It will also be appreciated that the introduction of the gain fiber into the capillary of the first optical device, and the introduction of the second fiber into the capillary of the first optical device, may be the same capillary, such as by introducing the gain fiber and the second fiber into the first optical device through a two-wire capillary (alternatively referred to as a two-wire fiber capillary, alternatively referred to as a two-wire fiber stub); it is also possible to introduce the gain fiber and the second fiber into the first optical device via two single-wire capillaries (alternatively referred to as single-wire fiber capillaries, alternatively referred to as single-wire fiber stubs), respectively.

The first optical device is connected to other optical devices or the optical fiber (i.e., the second optical fiber) for inputting/outputting optical signals has a different softening temperature or a different refractive index from the gain fiber.

The first optical device uses the optical signal input by the second optical fiber to reach the gain optical fiber through at least one section of free space, or the first optical device uses the optical signal input by the gain optical fiber to reach the second optical fiber through at least one section of free space. That is, the first optical device is connected to another optical device or an optical signal transmitted in an optical fiber that inputs/outputs an optical signal, and in the first optical device, the optical signal transmitted in the gain optical fiber or the optical signal transmitted in the gain optical fiber is reached at least through a space, and in the first optical device, the optical signal transmitted in the optical fiber (i.e., the second optical fiber) connected to another optical device or the optical signal that inputs/outputs the optical signal is reached at least through a space.

Taking WDM or isolator as an example, the optical fiber pigtail connecting the WDM or isolator with the gain fiber can be directly replaced by the gain fiber, thereby forming the optical fiber amplifier composed of heterogeneous fibers.

Example 1, as shown in fig. 6, a fiber amplifier may be composed of WDM, pump laser, isolator, and gain fiber. The existing heterogeneous optical fiber amplifier is improved to obtain the improved heterogeneous optical fiber amplifier. Specifically, the WDM and the fiber pigtail where the isolator is connected to the gain fiber can be directly replaced with the gain fiber. The optical fiber connected with the pump laser by WDM, the optical fiber for inputting optical signal by WDM and the optical fiber for outputting optical signal by isolator are all the second optical fiber.

As described above, the first optical device is directly connected to the gain fiber, and the first optical device is connected to other optical devices or the fiber that inputs/outputs an optical signal has a different softening temperature or a different refractive index from the gain fiber.

For example, the WDM and/or isolator is directly connected to the gain fiber.

As another example, the optical fiber (i.e., the second optical fiber) into which the WDM introduces the input optical signal has a different softening temperature or refractive index than the gain fiber.

As another example, the fiber (i.e., the second fiber) of the WDM-coupled pump laser has a different softening temperature or refractive index than the gain fiber.

As another example, the optical fiber (i.e., the second optical fiber) from which the isolator outputs the optical signal may have a different softening temperature or refractive index than the gain fiber.

The WDM shown in fig. 6, reference may be made to the WDM shown in fig. 9 below; and/or the isolator shown in fig. 6, may be referred to as the isolator shown in fig. 14, below.

Example 2, as shown in fig. 8, a fiber amplifier may be comprised of a WDM, a pump laser, an isolator, one or more fiber splices, and a gain fiber. In this example, one or more fiber adapters, such as adapter 1 and adapter 2, may be added. Specifically, the optical fiber pigtails connected to the gain optical fiber by the adapters 1 and 2 may be directly replaced by the gain optical fiber. And the optical fiber connected with the WDM by the adapter 1 and the optical fiber connected with the isolator by the adapter 2 are both second optical fibers.

As described above, the first optical device is directly connected to the gain fiber, and the first optical device has a different softening temperature or a different refractive index from the gain fiber to which another optical module or an optical signal is input/output.

For example, the adapter 1 or the adapter 2 may be directly connected to the gain fiber.

As another example, the softening temperature of the optical fiber (i.e., the second optical fiber) connected to the WDM of the adapter 1 is different from that of the gain optical fiber.

As another example, the softening temperature of the optical fiber (i.e., the second optical fiber) of the adapter 2 connected isolator is different from the softening temperature of the gain optical fiber.

Both the existing WDM and isolator can be adapted to the fiber amplifier shown in fig. 8.

It should be understood that, while the above describes the scheme 1 and the scheme 2 by way of example in conjunction with fig. 5 to 8, the embodiments of the present application are not limited thereto. For example, scheme 1 and scheme 2 may also be used in combination. For example, as in fig. 5 to 8, the partial optical device uses scheme 1, and the partial optical device uses scheme 2. As in fig. 5 or 6, the optical fiber to which the WDM is connected is the first optical fiber, and the isolator is directly connected to the gain fiber (or the gain fiber is directly introduced into or fitted into the isolator).

It should also be understood that the above-described schemes 1 and 2 are merely exemplary illustrations, and the embodiments of the present application are not limited thereto. For example, the first optical fiber may be an optical fiber having a softening temperature or refractive index close to that of the gain fiber.

According to the heterogeneous optical fiber amplifier provided by the embodiment of the application, the substrate of the optical fiber connected with the gain optical fiber is the same as or close to that of the gain optical fiber. Therefore, the heterogeneous optical fiber amplifier provided by the embodiment of the application can greatly reduce the connection loss of the heterogeneous optical fiber. Heterogeneous fiber connections are a common requirement for achieving L-band optical amplification, S-band optical amplification, and the like. Since the Spectral Efficiency (SE) of optical transmission is close to the shannon limit. Therefore, to further increase the transmission capacity of the optical fiber, an important direction is to spread the available spectrum from the C-band to the L-band and S-band. In order to achieve gain similar to that of the C-band optical amplifier, the gain fibers of the L-and S-band optical amplifiers are generally made of other substrate fibers different from the quartz glass substrate. However, the optical fiber on the line is the silica glass substrate optical fiber, and the tail fiber of the optical devices such as WDM and isolator in the existing optical amplifier module is also the silica glass substrate optical fiber, so that the L \ S optical amplifier needs to realize the heterogeneous optical fiber connection.

(1) As described above, the loss at the connection of the heterogeneous optical fiber in the embodiment of the present application is comparable to the loss of the fusion splice of the silica glass substrate optical fiber in the conventional optical amplifier (i.e., optical fiber amplifier). According to the heterogeneous optical fiber amplifier provided by the embodiment of the application, the loss of the heterogeneous optical fiber connection position is equivalent to the loss of the optical fiber connection position in the optical fiber amplifier composed of the homogeneous optical fiber, such as the loss of the fusion welding of the quartz glass substrate optical fiber in the existing optical fiber amplifier. The fusion loss of the quartz glass substrate optical fiber is about 0.1dB, if the heterogeneous optical fiber is directly fused, the loss can reach 0.5 dB-1 dB, and the loss of the heterogeneous optical fiber amplifier provided by the embodiment of the application can also reach a value close to 0.1dB theoretically. In particular, if the first optical device is directly connected to the gain fiber, the fusion-splice loss is even lower than that of the silica glass matrix fiber.

(2) After the heterogeneous optical fiber connection loss is reduced, the optical amplifier gain can be improved correspondingly. If one optical amplifier has four connecting points, the optical amplifier gain can be improved by 1.6-3.6 dB. One of the major problems with L/S band optical amplifiers is that the gain is small, and so it is important for L/S band optical amplifiers if the gain can be increased by this magnitude.

(3) After the connection loss of the heterogeneous optical fiber is reduced, the noise coefficient of the optical amplifier can be reduced. Especially, the connection loss before the first section of gain fiber has a large influence on the optical amplification noise figure. For example, compared with the existing fusion splicing scheme of the heterogeneous optical fiber, the heterogeneous optical fiber amplifier provided by the embodiment of the application can reduce the optical amplifier noise coefficient by 0.4-0.9 dB. Another major problem of the L/S band is that the noise figure is high, so the heterogeneous fiber amplifier provided by the embodiment of the present application is important for realizing practical L/S band optical amplification.

(3) Because the softening temperatures of the optical fibers with different matrixes are different, the fusion of the heterogeneous optical fibers is difficult, the failure probability is high, and the cost is high. Based on this application embodiment, can carry out homogeneous optical fiber fusion, consequently the processing degree of difficulty is low, with low costs.

Therefore, the optical amplifier module (including at least one first optical device) formed by the heterogeneous optical fiber provided by the embodiment of the application has the advantages that the connection loss of the heterogeneous optical fiber can be minimized, the optical amplifier module is beneficial to improving the optical amplifier gain, reducing the noise coefficient, reducing the processing difficulty and reducing the cost, and the optical amplifier module is expected to become a necessary technology for the optical amplifier in the L/S waveband.

The optical fiber amplifier provided by the embodiment of the present application is described above, and the optical devices that can constitute the optical fiber amplifier are described below. It is to be understood that the various optical devices described below may be used alone or in combination or in the fiber amplifiers described in fig. 4-8.

WDM suitable for use in embodiments of the present application is described in conjunction with fig. 9. The WDM may be the first optical device described in the embodiment of fig. 4. The WDM of fig. 9 may be used in the optical fiber amplifiers described in fig. 4-8.

Fig. 9 shows a schematic diagram of a WDM suitable for use in embodiments of the present application. One or more lenses, such as lens 1 and lens 2, may be included in the WDM. The WDM may also include WDM diaphragms, single-wire capillaries (e.g., single-wire capillary 1), and double-wire capillaries (e.g., double-wire capillary 1).

A single-wire capillary, which may also be referred to as a single-wire fiber capillary, for example, is understood by those skilled in the art to mean, for example, a single-wire fiber tip may also be substituted. A two-wire capillary, which may also be referred to as a two-wire fiber capillary, for example, is understood by those skilled in the art to mean, for example, a two-wire fiber tip may also be substituted. Hereinafter, for uniformity, both are indicated by a single-line capillary and a double-line capillary.

Alternatively, embodiments of the present application may employ WDM of spatial optical paths. By the mode, the problem of fusion caused by the softening temperature of the optical fiber glass of different matrixes can be avoided. Alternatively, other types of WDM may be used, without limitation.

The WDM module can be used to perform the function of combining or combining the signal light and the pump light. As shown in fig. 9, the signal light is sent to the WDM diaphragm through the second optical fiber, and the pump light is also sent to the WDM diaphragm through the second optical fiber. The WDM film can combine the signal light and the pump light to form mixed light. It should be understood that the mixed light is only named for distinguishing, and the mixed light may also be called a combined wave light, and the name does not limit the protection scope of the embodiments of the present application. The following is collectively represented by mixed light.

Taking fig. 9 as an example, one possible flow is as follows.

(1) The single-wire capillary 1 receives an optical signal from a second optical fiber (i.e., a signal light input optical fiber) and sends the optical signal to the lens 1. It is understood that the optical signal in the input optical signal is a general optical signal, that is, it means that the optical signal is introduced or inputted, that is, the optical signal inputted by the second optical fiber is the signal light.

In one possible implementation, the second fiber may be stripped of its coating, inserted into a capillary, then beveled and coated.

(2) The lens 1 mainly collimates the light beam of the optical signal (i.e., the light beam of the signal light here) sent from the single-wire capillary 1.

The single-wire capillary 1 sends the signal light into a space where the signal light is scattered. Therefore, the signal light can be collimated by the lens 1 to become parallel light or approximately parallel light.

(3) The WDM film mainly realizes the wave combination or the combination of the signal light sent by the lens 1 and the pump light sent by the lens 2.

One possible implementation is shown in fig. 10. The substrate is coated with a multilayer film, the pump light sent by the lens 2 is incident through the multilayer film, the signal light sent by the lens 1 is incident through the substrate, and the generated mixed light after wave combination is emitted to the lens 2 through the multilayer film.

It should be understood that the above-described flow is only an exemplary illustration, and the embodiments of the present application are not limited thereto. In practice, the pump light may be fed through the single-wire capillary 1, and the signal light may be fed through the two-wire capillary 1. In addition, the WDM in fig. 5 and fig. 6 is a WDM for providing forward pumping, and in fact, the WDM can also be used for providing backward pumping, and the embodiment of the present application is not limited thereto. When WDM is used to provide backward pumping, the WDM is similar in structure to WDM providing forward pumping (see fig. 9) in that the signal light is the output, the pump light is the input, and the mixed light has both the input and the output. The working principle is similar whether forward pumping WDM or backward pumping WDM, so the implementation of the two is similar, and the description is omitted.

In the embodiment of the present application, the hybrid optical output fiber in WDM is the first fiber (scheme 1) or the gain fiber (scheme 2), and the signal optical input fiber and the pump optical input fiber are the second fibers.

Regarding the first optical fiber and the second optical fiber, reference is made to the above description, which is not repeated below.

Alternatively, the beam of mixed light and pump light may be conditioned or collimated by any of the following means.

Mode 1, the angle between the two optical fibers in the double-wire capillary is adjusted so that the two optical fibers in the double-wire capillary are not parallel, so as to collimate the beam of the pump light and the beam of the mixed light.

As can be seen from fig. 9, the WDM in fig. 9 is a WDM supporting forward pumping, and the main functions of the two-wire capillary 1 include: the pump light is introduced from the pump light input fiber (i.e., the second fiber) to the lens 2, and the mixed light sent from the lens 2 is received and sent to the mixed light output fiber (the first fiber or the gain fiber). Or the signal light is introduced from the signal light input fiber (i.e., the second fiber) to the lens 2, and the mixed light sent from the lens 2 is received to the mixed light output fiber. If the WDM is a backward pumping enabled WDM, the main functions of the two-wire capillary 1 include: the pumping light is introduced from the pumping light input fiber (i.e. the second fiber) and sent to the lens 2, and part of the mixed light from the lens 2 to the mixed light output fiber (the first fiber or the gain fiber) is sent from the lens 2 to the mixed light output fiber, and part of the mixed light is sent from the mixed light output fiber to the lens 2, and the "mixed light output fiber" is only a name and does not represent the transmission direction of the optical signal in the fiber; or the signal light is introduced from the signal light input fiber (i.e. the second fiber) and sent to the lens 2, and part of the mixed light from the lens 2 to the mixed light output fiber (the first fiber or the gain fiber) is sent from the lens 2 to the mixed light output fiber, and part of the mixed light is sent from the mixed light output fiber to the lens 2, in this case, the "mixed light output fiber" is merely a name and does not represent the transmission direction of the optical signal in the fiber.

As an example, the angle between two fibers in a two-wire capillary (i.e., the two-wire capillary 1) can be designed according to the refractive index of the first fiber or the gain fiber so as to collimate the beam of mixed light.

For example, the angle between the hybrid light output fiber (first fiber or gain fiber) and the pump light input fiber/signal light input fiber (second fiber) can be adjusted according to the refraction principle and the refractive index of the hybrid light output fiber (first fiber or gain fiber), so that the hybrid light beam is aligned with the corresponding position of the WDM film.

As shown in fig. 11, the angle Δ θ between the first fiber/gain fiber and the second fiber in the twin capillary 1 is θ₄-θ₃Assume that the refractive index of the first fiber/gain fiber is n1 and the refractive index of the second fiber is n 2. In general, the two beams are parallel in the lens, i.e. the two beams pass through free space to the refraction angle theta of the lens₁The same is true. Assuming that the refractive indexes of all parts in the lens are the same, the refraction angle from the lens 2 to the free space of the two light beams and the refraction angle theta from the free space to the double-wire capillary tube₂Similarly, there is sin θ according to the law of refraction₂＝n1*sinθ₃＝n2*sinθ₄. When designed, theta₂The optimum incident angle/emergent angle of the WDM diaphragm, the structures and optical parameters of the WDM diaphragm, the lens and the double-line capillary can be set, so that the included angle between the first optical fiber/gain optical fiber and the second optical fiber in the double-line capillary 1 can be calculated according to the formula.

Mode 2, adjusting the light beams of the optical signals in the two optical fibers in the two-wire capillary by a lens, for example, adjusting the light spots or the mode spots of the optical signals input to or output from the two optical fibers in the two-wire capillary by a lens so as to collimate the light beams of the pump light and the light beams of the mixed light, and/or aligning the light spots or the mode spots (including the size of the light spots or the mode spots, and/or the divergence angle of the light spots or the mode spots, etc.) of the optical signals in the two optical fibers in the two-wire capillary on the WDM membrane.

The lens may primarily provide collimation of the spatial light path while also adjusting the spot or spot size of the beam, e.g. to provide collimation of beams having different diameters, and/or different divergence angles, onto parallel (or near parallel) beams having the same or similar spot or spot size. In the embodiment of the present application, the lens (i.e., lens 2 in fig. 9) may be a lens supporting dual optical paths.

One possible design could be to use an aspherical C lens as shown in fig. 12.

The radius of curvature of the upper half of the C lens (i.e., lens 2 in fig. 9) is small, and the radius of curvature of the lower half is large. In other words, the radius of curvature of the C-lens corresponding to the mixed optical path (i.e. corresponding to the first optical fiber or the gain optical fiber) is smaller than the radius of curvature of the C-lens corresponding to the pump optical path (i.e. corresponding to the second optical fiber). Compared with the existing spherical C lens supporting double light paths, the C lens provided by the embodiment of the application is more flexible and has more application scenes.

It will be appreciated that in this C-lens the size of the radius of curvature is relative, i.e. the radius of curvature of the upper part is relatively small in relation to the radius of curvature of the lower part. The values of the curvature radius of the upper and lower portions are not limited.

It should also be understood that in the C lens, the portion occupied by the curved surface having a small radius of curvature and the portion occupied by the curved surface having a large radius of curvature are not limited. The curvature radius of the corresponding mixed light path is smaller than that of the corresponding pump light path, and the mixed light path and the pump light path are all applicable to the embodiment of the application.

Yet another possible design may use an asymmetric G-lens, as shown in fig. 13.

The refractive index of the upper half of the G lens (i.e., lens 2 in fig. 9) changes faster in the radial direction than the lower half. In other words, the refractive index of the G-lens along the radial direction changes faster with respect to the optical path of the mixed light (i.e., the optical path corresponding to the first optical fiber or the gain optical fiber) than with respect to the optical path of the pump light (i.e., the optical path corresponding to the second optical fiber). Compared with the existing G lens supporting double light paths, the G lens provided by the embodiment of the application is more flexible and has more application scenes.

It will be appreciated that in this G lens the speed of the refractive index change in the radial direction is relatively slow, i.e. the refractive index change in the radial direction is relatively fast for the upper part relative to the lower part. The refractive index of the upper and lower portions varies along the radial direction, and is not limited.

It should also be understood that the embodiments are applicable as long as the refractive index of the corresponding mixed light path changes faster in the radial direction than the refractive index of the corresponding pump light path.

The above two designs are merely exemplary, and the embodiments of the present application are not limited thereto.

Based on the above mode 2, a lens, such as an aspheric C lens or an asymmetric G lens, may be used to achieve alignment of the light beams of different host fibers, and/or alignment of the light beams of different host fibers, the light spots or mode spots (including the size of the light spots or mode spots, and/or the divergence angle of the light spots or mode spots, etc.) at selected positions (e.g., the WDM diaphragm surface), i.e., to collimate the light beam of the optical signal (e.g., the mixed light beam) in the first fiber or the gain fiber with the light beam of the optical signal (e.g., the pump light beam) in the second fiber, and/or to adjust the mode spots or light spots of the light beam of the optical signal in the first fiber or the gain fiber with the light beam of the optical signal in the second fiber.

It should be understood that the above-mentioned modes 1 and 2 are only exemplary, and any scheme capable of collimating the light beam of the optical signal (such as collimating the light beam of the mixed light and the pump light) and/or adjusting the mode/spot of the light beam can be used in the embodiments of the present application.

In the embodiment of the present application, the light signal spots or the optical signal spots (including the size and/or the divergence angle of the light spots or the optical signal spots) may be the same or different, and the following mainly describes the case where the light signal spots are different.

Alternatively, the mode spot of the hybrid light output fiber (first fiber or gain fiber) may be smaller than the mode spot of the pump light input fiber (second fiber), i.e., Φ 3< Φ 1; and/or the mode spot of the mixed light output fiber may be smaller than the mode spot of the signal light input fiber (second fiber), i.e., Φ 3< Φ 2. The mode spot of the WDM membrane for receiving the pump light and the mode spot of the mixed light output by the WDM membrane should be the same or similar, i.e. phi 4 is approximately equal to phi 5.

In the case of the double-wire capillary 1 in the embodiment of the present application, the fiber mode spot corresponding to the optical path of the mixed light is smaller than that corresponding to the optical path of the pump light, i.e., Φ 3< Φ 2.

Example 1, the lens (i.e., lens 2) supports a different mode spot of the optical path of the mixed light from the mode spot of the optical path of the pump light.

For example, the lens may be designed according to the spot of the mixed light path and the spot of the pump light path. Such as the radius of curvature or refractive index profile of the lens, can be designed to adjust its focal length. The lens may be the lens shown in fig. 12 or fig. 13.

Based on the above example 1, a lens such as an aspherical C lens or an asymmetric G lens may be employed, and the fiber mode spot supporting the optical path of the mixed light is different from the fiber mode spot corresponding to the optical path of the pump light.

Example 2, a two-wire capillary (i.e., two-wire capillary 1) was designed to support a different mode spot of the optical path of the mixed light than that of the pump light.

For example, the double-wire capillary can be designed according to the mode spot of the mixed light path and the mode spot of the pumping light path. The position of the two-wire capillary can be designed, for example, to be aligned with the focal point of the lens. The bidirectional capillary 1 can be used for stripping the coating layers of the mixed light output fiber (first fiber or gain fiber) and the pump light input fiber (second fiber), inserting the fiber into the capillary, grinding the fiber into an inclined plane and coating the film.

Example 3, pump light input fiber (second fiber) was adjusted. For example, a silica glass matrix fiber matched to the mode spot of the mixed light output fiber (first fiber or gain fiber) is selected as the pump light input fiber.

Based on the embodiments of the present application, the WDM provided by the embodiments of the present application can change the connection mode between the WDM and the gain fiber in the fiber amplifier. In the optical fiber amplifier, the interface between the WDM and the gain fiber can be changed into the interface of the homogeneous fiber (or close to the homogeneous fiber) (i.e. scheme 1, if the first fiber is the same as or close to the matrix of the gain fiber, or the refractive index of the first fiber and the refractive index of the gain fiber are close to each other and/or the softening temperature of the first fiber is close to each other), or the interface is not needed at all (i.e. scheme 2, the WDM is directly connected with the gain fiber), so that the problem caused by fusion splicing of the heterogeneous fiber can be avoided.

WDM suitable for use in embodiments of the present application is described above in connection with fig. 9-13. An isolator suitable for use in embodiments of the present application is described below in conjunction with fig. 14. The isolator may be the first optical device described in the embodiment of fig. 4. The isolator shown in fig. 14 may be used in the fiber amplifier described in fig. 4 to 8. The isolator shown in fig. 14 may be used separately from the WDM shown in fig. 9 or may be used in combination.

FIG. 14 shows a schematic view of an isolator suitable for use with embodiments of the present application. One or more lenses, such as lens 3 and lens 4, may be included in the isolator. The isolator also comprises an optical isolator central device and at least one single-wire capillary (such as a single-wire capillary 2 and a single-wire capillary 3). Illustratively, the optically isolated center device may include, for example: wedge birefringent crystals (such as wedge birefringent crystal 1 and wedge birefringent crystal 2), and Faraday rotators.

The isolator is used for allowing optical signals transmitted in one direction to pass through or allowing optical signals transmitted in one direction to be less lost, and allowing optical signals transmitted in the opposite direction to not pass through or to be more lost. The isolator may be used to suppress transmission of reflected light that may be behind the output fiber (e.g., the amplified signal light output fiber in fig. 14). The amplified signal light is sent to the optical isolator core through an amplified signal light input fiber (first fiber or gain fiber) and then to an amplified signal light output fiber (second fiber). Possible reflected light after the amplification of the signal light output fiber can be sent to the optical isolator central part through the amplification of the signal light output fiber, but cannot be sent to the amplification of the signal light input fiber after passing through the optical isolator central part, so that the reverse transmission of the possible reflected light is inhibited.

Taking fig. 14 as an example, one possible flow is as follows.

(1) The single-wire capillary 2 introduces the amplified signal light from the first optical fiber or the gain optical fiber (i.e., the amplified signal light input optical fiber) and sends the amplified signal light to the lens 3.

In one possible implementation, the first fiber or gain fiber may be stripped of its coating, inserted into a capillary, then beveled and coated. The lens 3 mainly collimates the signal light sent from the single-wire capillary 2. The single-wire capillary 2 sends the signal light into a space where the signal light is scattered. Therefore, the signal light can be collimated by the lens 3 to be parallel light or approximately parallel light.

(2) The optical isolator centerpiece serves as a core of the optical isolator and can be used for realizing unidirectional transmission of optical signals.

In one possible implementation, the optical isolator center sends the amplified signal light received from the lens 3 to the lens 4, and sends the lower-stage possible reflected light sent from the lens 4 to the lens 3 in a direction deviating from the optical path from the single-wire capillary 2 to the lens 3. Due to the deviation from the direction, the lens 3 receives the lower possible reflected light and cannot couple it into the amplified signal light input fiber. As an example, the optical isolator centerpiece may be constructed of 2 pieces of a wedge-shaped birefringent crystal, a magnet, and a Faraday rotator made of yttrium iron garnet.

(3) The lens 4 receives the amplified signal light sent by the optical isolator central part, sends the amplified signal light to the single-wire capillary 3, and finally outputs the amplified signal light through an amplified signal light output optical fiber (namely, a second optical fiber). This part is similar in function and implementation to the amplified signal light input fiber, the single-wire capillary 2, and the lens 3, but in the opposite direction. And will not be described in detail herein.

It should be understood that the above-described flow is only an exemplary illustration, and the embodiments of the present application are not limited thereto.

In the embodiment of the present application, the amplified signal light input optical fiber is a first optical fiber (scheme 1) or a gain optical fiber (scheme 2), and the amplified signal light output optical fiber is a second optical fiber.

Regarding the first optical fiber and the second optical fiber, reference is made to the above description, which is not repeated below.

Alternatively, the beam of the amplified signal light may be adjusted or collimated by any of the following means.

In the mode 1, the included angle between the optical fibers in the single capillary 2 and the single capillary 3 is adjusted, so that the optical fibers in the single capillary 2 and the single capillary 3 are not parallel, and the amplified light beam of the signal light is collimated.

As an example, the angle between the optical fibers in the single-wire capillary 2 and the single-wire capillary 3 may be adjusted by the refractive index of the first optical fiber or the gain optical fiber and the refractive index of the second optical fiber so as to collimate or adjust the beam of the amplified signal light.

For example, the position of the amplified signal light input fiber in the single capillary 2 may be adjusted based on the principle of refraction and the refractive index of the amplified signal light input fiber to collimate the beam of the amplified signal light, e.g., to align the beam of the amplified signal light with a corresponding position of the optical isolator centerpiece.

Specifically, reference may be made to the description of the mode 1 in the embodiment shown in fig. 9, and details are not described here again.

Mode 2, the beam of the optical signal of the optical fiber in the single capillary tube is adjusted by a lens, for example, the spot or spot of the optical signal of the optical fiber in the single capillary tube is adjusted by a lens, so as to collimate the beam of the amplified signal light, and/or to align the spot or spot (including the size of the spot or spot, and/or the divergence angle of the spot or spot, etc.) of the optical signal of the optical fiber in the single capillary tube 2 and the spot or spot of the optical signal of the optical fiber in the single capillary tube 3 on the isolator middleware.

As shown in fig. 14, lens 3 in the isolator is used to collimate and/or collimate the beam of the optical signal of the optical fiber in the single wire capillary 2 (the beam of the optical signal of the first optical fiber or the gain fiber), and lens 4 in the isolator is used to collimate and/or collimate the beam of the optical signal of the optical fiber in the single wire capillary 3 (the beam of the optical signal of the second optical fiber).

Optionally, the focal length of lens 3 is smaller than the focal length of lens 4.

It should be understood that the above-mentioned modes 1 and 2 are only exemplary, and any scheme capable of collimating and/or adjusting the light beam of the optical signal (e.g., collimating and/or adjusting the light beam of the amplified signal light) can be used in the embodiments of the present application.

In the embodiment of the present application, the light signal spots or the optical signal spots (including the size and/or the divergence angle of the light spots or the optical signal spots) may be the same or different, and the following mainly describes the case where the light signal spots are different.

Alternatively, the mode spot of the amplified signal light input fiber (first fiber or gain fiber) may be smaller than that of the amplified signal light output fiber (second fiber), i.e., Φ 6< Φ 7. The mode spot Φ 8 of the amplified signal light received by the optical isolator centerpiece is related to the mode spot Φ 9 of the amplified signal light transmitted by the optical isolator centerpiece, and Φ 9 is related to Φ 7.

Example 1, a lens (e.g., lens 3) supports a different mode spot of the amplified signal light output fiber than that of the amplified signal light input fiber.

For example, the lens 3 may be designed according to the mode spot of the amplified signal light output fiber and the amplified signal light input fiber. Such as the radius of curvature or the refractive index profile of the lens 3.

Based on the above example 1, a lens supporting the difference in the mode spot of the amplified signal light output optical fiber and the amplified signal light input optical fiber may be employed.

Example 2, a single-wire capillary (e.g., single-wire capillary 2 and single-wire capillary 3) was designed to support a different mode spot of the amplified signal light output fiber than that of the amplified signal light input fiber.

For example, the single-wire capillary 2 and the single-wire capillary 3 may be designed to be aligned with the corresponding positions of the optical isolator centerpieces, based on the mode spots of the amplified signal light output optical fiber and the amplified signal light input optical fiber. For example, the positions of the single-strand capillary 2 and the single-strand capillary 3 can be designed.

Example 3, the amplified signal light output fiber (second fiber) is adjusted. For example, a silica glass substrate optical fiber matched with the mode spot of an amplified signal light input optical fiber (first optical fiber or gain optical fiber) is selected as the amplified signal light output optical fiber.

Based on the embodiment of the application, the isolator provided by the embodiment of the application can change the connection mode of the isolator and the gain fiber in the fiber amplifier. In the optical fiber amplifier, the butt joint of the isolator and the gain fiber can be changed into the butt joint of a homogeneous fiber (or close to the homogeneous fiber) (namely, in the scheme 1, if the first fiber is the same as or close to the matrix of the gain fiber, or the refractive index of the first fiber and the refractive index of the gain fiber are close and/or the softening temperature of the first fiber is close), or the butt joint is completely not needed (namely, in the scheme 2, the isolator is directly connected with the gain fiber), so that the problems caused by fusion splicing of the heterogeneous fibers can be avoided.

A WDM suitable for use in embodiments of the present application is described above with reference to fig. 9-13, an isolator suitable for use in embodiments of the present application is described with reference to fig. 14, and a fiber optic adapter suitable for use in embodiments of the present application is described below with reference to fig. 15. The optical fiber adapter may be the first optical device described in the embodiment of fig. 4. The optical fiber adapter shown in fig. 15 can be used in the optical fiber amplifier described in fig. 4 to 8. The optical fiber adapter shown in fig. 15 may be used alone or in combination with the WDM shown in fig. 9 and the isolator shown in fig. 14.

Figure 15 shows a schematic diagram of a fiber optic adapter suitable for use with embodiments of the present application. One or more lenses, such as lens 5 and lens 6, may be included in the fiber optic adapter. The optical fiber adapter may further include at least one single wire capillary, such as a single wire capillary 4 and a single wire capillary 5. The optical fiber adapter may also be recorded as a heterogeneous optical fiber adapter or adapter, for example. The optical fiber adapter may be the adapter 1 shown in fig. 7 or fig. 8, or may be the adapter 2 shown in fig. 7 or fig. 8.

The optical fiber adapter is used for connecting the first optical fiber and the second optical fiber, or the optical fiber adapter is used for connecting the second optical fiber and the gain optical fiber. The optical fiber adapter can be used for realizing optical fiber space coupling with different refractive indexes or softening temperatures, so that the loss of optical fiber connection is reduced.

Since the optical path is reversible, the optical signal in fig. 15 can be input from the optical fiber 1 and output from the optical fiber 2; alternatively, the optical signal in fig. 15 may be input from the optical fiber 2 and output from the optical fiber 1. The optical fiber 1 is a first optical fiber or a gain optical fiber, and the optical fiber 2 is a second optical fiber; alternatively, the optical fiber 2 is a first optical fiber or a gain optical fiber, and the optical fiber 1 is a second optical fiber.

For example, in the case where the optical fiber adapter shown in fig. 15 is the adapter 1 shown in fig. 7, the optical fiber 1 may be the second optical fiber, and the optical fiber 2 may be the first optical fiber.

For another example, in the case that the optical fiber adapter shown in fig. 15 is the adapter 2 shown in fig. 7, the optical fiber 1 may be a first optical fiber, and the optical fiber 2 may be a second optical fiber.

For another example, in the case that the optical fiber adapter shown in fig. 15 is the adapter 1 in fig. 8, the optical fiber 1 may be a second optical fiber, and the optical fiber 2 may be a gain optical fiber.

For another example, in the case that the optical fiber adapter shown in fig. 15 is the adapter 2 shown in fig. 8, the optical fiber 1 may be a gain optical fiber, and the optical fiber 2 may be a second optical fiber.

Taking the example that the optical signal is input from the optical fiber 1 and the mode spot of the optical fiber 1 is smaller than that of the optical fiber 2, a possible flow is that the optical signal is input from the optical fiber 1, and the single-wire capillary 4 introduces the optical signal from the optical fiber 1 and sends the optical signal to the lens 5. Lens 5 collimates the optical signal and feeds it to lens 6. The lens 6 couples the optical signal into the single-wire capillary 5 and the optical fiber 2.

Alternatively, the angle between the optical fibers in the single capillary 4 and the single capillary 5 is adjusted so that the optical fibers in the single capillary 4 and the single capillary 5 are not parallel in order to collimate the beam of the light signal (the beam of amplified signal light).

Optionally, the beam of the optical signal of the optical fiber in the single capillary tube is adjusted by a lens, e.g. the spot or spot of the optical signal of the optical fiber in the single capillary tube is adjusted by a lens, in order to collimate the beam of the optical signal (the beam of amplified signal light), and/or to align the spot or spot of the optical signal of the optical fiber in the single capillary tube 4 and the spot or spot of the optical signal of the optical fiber in the single capillary tube 5 between the lens 5 and the lens 6 (including the size of the spot or spot, and/or the divergence angle of the spot or spot, etc.).

Optionally, a focal length of a lens used to introduce the first fiber or gain fiber feed optical fiber adapter is less than a focal length of a lens used to introduce the second fiber feed optical fiber adapter.

Optionally, a lens (e.g., lens 5 or lens 6) supports that the mode spot of fiber 1 is different from the mode spot of fiber 2.

Alternatively, a single-wire capillary (e.g., single-wire capillary 4 or single-wire capillary 5) is designed to support a mode spot of optical fiber 1 that is different from a mode spot of optical fiber 2.

For the single wire capillary 4, reference may be made to the single wire capillary 2 shown in fig. 14, for the single wire capillary 5, reference may be made to the single wire capillary 3 shown in fig. 14, for the lens 5, reference may be made to the lens 3 shown in fig. 14, and for the lens 6, reference may be made to the lens 4 shown in fig. 14, which is not described again here. Alternatively, for the single capillary 5, reference may be made to the single capillary 2 shown in fig. 14, for the single capillary 4, reference may be made to the single capillary 3 shown in fig. 14, for the lens 6, reference may be made to the lens 3 shown in fig. 14, and for the lens 5, reference may be made to the lens 4 shown in fig. 14, which is not described again here.

Based on the embodiment of the application, the optical fiber adapter provided by the embodiment of the application can change the connection mode of each optical module and the gain optical fiber in the optical fiber amplifier. In the optical fiber amplifier, the optical fiber adapter and the gain optical fiber can be butted to a homogeneous optical fiber (or close to the homogeneous optical fiber) (i.e. scheme 1, if the first optical fiber is an optical fiber with the same or close to the matrix of the gain optical fiber, or the refractive index of the first optical fiber and the refractive index of the gain optical fiber are close and/or the softening temperature of the first optical fiber and the gain optical fiber are close), or the butt joint is not needed at all (i.e. scheme 2, the optical fiber adapter is directly connected with the gain optical fiber). The butt joint of the optical fiber adapter and the WDM or isolator can be changed into the butt joint of a homogeneous optical fiber (or close to the homogeneous optical fiber) (for example, the substrate of the optical fiber connected with the optical fiber adapter and the WDM or isolator is the same as that of the second optical fiber), or the butt joint is not required at all (that is, the optical fiber connected with the optical fiber adapter and the WDM or isolator is the second optical fiber), so that the problems caused by fusion splicing of heterogeneous optical fibers can be avoided.

In the foregoing embodiments, the WDM, the isolator, and the optical fiber adapter are taken as examples for illustration, and are not limited thereto. The present invention is applicable to the embodiments as long as the optical fibers of the optical device connecting different optical modules (or optical devices) are not completely the same. In one example, the optical device is directly connected to the gain fiber, and the optical fiber connected to another optical device or inputting/outputting an optical signal is a different optical fiber from the gain fiber. As yet another example, the optical device connects the gain fiber using a first optical fiber, connects other optical devices using an optical fiber different from the first optical fiber, or inputs/outputs optical signals.

Embodiments of apparatus (e.g., optical devices, fiber amplifiers) suitable for use in embodiments of the present application are described above with reference to fig. 4-15, and method embodiments of the present application are described in detail below with reference to fig. 16-19. The description of the apparatus side and the description of the method side correspond to each other, and the overlapping description is appropriately omitted for the sake of brevity.

Fig. 16 is a schematic flow chart of a method for manufacturing a light device according to an embodiment of the present application. The optical device obtained based on the method 1600 of fig. 16 may be the aforementioned first optical device (the first optical device in scheme 1), or may also be used in the aforementioned optical fiber amplifier (the optical fiber amplifier in scheme 1). The method 1600 may include the following steps.

1610, a first optical fiber is adopted to connect with a gain optical fiber, and the gain optical fiber is used for amplifying optical signals;

1620, the optical signal is input to one or more second optical devices by using a second optical fiber, and/or the optical signal is amplified by using a second optical fiber or an output gain fiber, wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indexes.

In one example, the difference (or the absolute value of the difference) in the softening temperatures of the first and second optical fibers is greater than the difference (or the absolute value of the difference) in the softening temperatures of the first and gain optical fibers.

As yet another example, the difference in refractive index (or the absolute value of the difference) between the first and second optical fibers is greater than the difference in refractive index (or the absolute value of the difference) between the first and gain optical fibers.

As yet another example, the matrix of the first optical fiber is the same as the matrix of the gain optical fiber.

As yet another example, an optical signal input through the second optical fiber reaches the first optical fiber through at least a section of free space; alternatively, an optical signal input through the first optical fiber reaches the second optical fiber through at least a section of free space.

In yet another example, the first optical fiber and/or the second optical fiber stripped of the coating layer is introduced into or assembled to the optical device through at least one capillary.

In another example, the first optical fiber and the gain optical fiber are connected by fusion splicing.

As yet another example, the light device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter.

In yet another example, the optical device is a WDM, the WDM comprising a two-wire capillary through which two optical fibers are introduced into the WDM; one of the two optical fibers is a first optical fiber; the other of the two optical fibers is a second optical fiber, and the other of the two optical fibers is used for: and connecting a pump laser, or inputting an optical signal or outputting an optical signal amplified by the gain fiber.

As yet another example, the two fibers in a twin capillary are not parallel.

In yet another example, the WDM includes a first lens through which beams of optical signals in two optical fibers in the two-wire capillary are adjusted.

For yet another example, the radius of curvature of the curved portion of the optical path of the optical signal in the first optical fiber corresponding to the first lens is smaller than the radius of curvature of the curved portion of the optical path of the optical signal in the second optical fiber corresponding to the first lens; or the radial refractive index change of the optical path of the optical signal corresponding to the first optical fiber by the first lens is faster than that of the optical path of the optical signal corresponding to the second optical fiber by the first lens.

As yet another example, the first lens supports a difference in mode spot of the optical signal in the two optical fibers in the two-wire capillary.

As yet another example, the mode spots of the optical signals in the two optical fibers in a two-wire capillary are matched.

In yet another example, the optical device is an isolator comprising a first single-wire capillary through which the first optical fiber is introduced into the isolator and a second single-wire capillary through which the second optical fiber is introduced into the isolator.

For yet another example, the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

In yet another example, the isolator includes a second lens through which the beam of the optical signal of the optical fiber in the first singlet capillary is adjusted and a third lens through which the beam of the optical signal of the optical fiber in the second singlet capillary is adjusted.

In yet another example, the focal length of the second lens is less than the focal length of the third lens.

In another example, the optical device is an optical fiber adapter, the optical fiber adapter includes a third single-wire capillary and a fourth single-wire capillary, the first optical fiber is introduced into the optical fiber adapter through the third single-wire capillary, and the second optical fiber is introduced into the optical fiber adapter through the fourth single-wire capillary.

For yet another example, the optical fiber in the third single-wire capillary and the optical fiber in the fourth single-wire capillary are not parallel.

In yet another example, the optical fiber adapter includes a fourth lens through which the optical beam of the optical signal of the optical fiber in the third singlet capillary is adjusted and a fifth lens through which the optical beam of the optical signal of the optical fiber in the fourth singlet capillary is adjusted.

For yet another example, the focal length of the fourth lens is less than the focal length of the fifth lens.

Fig. 17 is a schematic flow chart of a method of manufacturing a light device according to yet another embodiment of the present application. The optical device obtained based on the method 1700 of fig. 17 may be the aforementioned first optical device (first optical device in scheme 2), or may be used in the aforementioned optical fiber amplifier (optical fiber amplifier in scheme 2). Method 1700 may include the following steps.

1710, directly connecting a gain fiber, wherein the gain fiber is used for amplifying optical signals;

1720, connecting the one or more second optical devices with a second optical fiber, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain fiber with the second optical fiber, wherein the second optical fiber and the gain fiber have different softening temperatures and/or refractive indexes.

In one example, an optical signal input through the second optical fiber reaches the gain optical fiber through at least a section of free space; alternatively, the optical signal input through the gain fiber reaches the second fiber through at least a section of free space.

In yet another example, the gain fiber and/or the second fiber with the coating layer stripped off is introduced into or assembled to the optical device through at least one capillary.

As yet another example, the light device is any one or more of: wavelength division multiplexer WDM, isolator, optical fiber adapter.

In yet another example, the optical device is a WDM, the WDM comprising a two-wire capillary through which two optical fibers are introduced into the WDM; one of the two optical fibers is a gain optical fiber; the other of the two optical fibers is a second optical fiber, and the other of the two optical fibers is: the optical fiber is used for connecting a pump laser, or used for inputting an optical signal, or used for outputting an optical signal amplified by a gain fiber.

As yet another example, the two fibers in a twin capillary are not parallel.

In yet another example, the WDM includes a first lens through which beams of optical signals in two optical fibers in the two-wire capillary are adjusted.

For yet another example, the radius of curvature of the curved portion of the optical path of the optical signal in the gain fiber corresponding to the first lens is smaller than the radius of curvature of the curved portion of the optical path of the optical signal in the second fiber corresponding to the first lens; or the radial refractive index change of the optical path of the optical signal corresponding to the gain optical fiber by the first lens is faster than that of the optical path of the optical signal corresponding to the second optical fiber by the first lens.

As yet another example, the first lens supports a difference in mode spot of the optical signal in the two optical fibers in the two-wire capillary.

As yet another example, the mode spots of the optical signals in the two optical fibers in a two-wire capillary are matched.

In yet another example, the optical device is an isolator comprising a first single-wire capillary through which the gain fiber is introduced into the isolator and a second single-wire capillary through which the second fiber is introduced into the isolator.

For yet another example, the optical fiber in the first single-wire capillary and the optical fiber in the second single-wire capillary are not parallel.

In yet another example, the isolator includes a second lens through which the beam of the optical signal of the optical fiber in the first singlet capillary is adjusted and a third lens through which the beam of the optical signal of the optical fiber in the second singlet capillary is adjusted.

In yet another example, the focal length of the second lens is less than the focal length of the third lens.

In another example, the optical device is an optical fiber adapter, the optical fiber adapter includes a third single-wire capillary and a fourth single-wire capillary, the gain optical fiber is introduced into the optical fiber adapter through the third single-wire capillary, and the second optical fiber is introduced into the optical fiber adapter through the fourth single-wire capillary.

For yet another example, the optical fiber in the third single-wire capillary and the optical fiber in the fourth single-wire capillary are not parallel.

In yet another example, the optical fiber adapter includes a fourth lens through which the optical beam of the optical signal of the optical fiber in the third singlet capillary is adjusted and a fifth lens through which the optical beam of the optical signal of the optical fiber in the fourth singlet capillary is adjusted.

For yet another example, the focal length of the fourth lens is less than the focal length of the fifth lens.

Fig. 18 is a schematic flow chart of a method for manufacturing an optical fiber amplifier according to an embodiment of the present application. The fiber amplifier obtained based on the method 1800 of fig. 18 may be the fiber amplifier mentioned earlier (fiber amplifier in case 1). Method 1800 may include the following steps.

1810, connecting a first optical device with a gain fiber by using a first optical fiber, wherein the gain fiber is used for amplifying an optical signal;

1820, connecting the first optical device with one or more second optical devices by using a second optical fiber, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain fiber by using the second optical fiber, wherein the first optical fiber and the second optical fiber have different softening temperatures and/or refractive indexes.

The first optical device is the above-mentioned first optical device, and is not described herein again.

FIG. 19 is a schematic flow chart diagram of a method of manufacturing an optical fiber amplifier according to yet another embodiment of the present application. The optical fiber amplifier obtained based on the method 1900 of fig. 19 may be the aforementioned optical fiber amplifier (optical fiber amplifier in scheme 2). Method 1900 may include the following steps.

1910, directly connecting the first optical device with a gain fiber, the gain fiber being for amplifying an optical signal;

1920, connecting the first optical device with one or more second optical devices by using a second optical fiber, and/or inputting an optical signal into the second optical fiber or outputting an optical signal amplified by the gain optical fiber by using the second optical fiber, wherein the second optical fiber and the gain optical fiber have different softening temperatures and/or refractive indexes.

The first optical device is the above-mentioned first optical device, and is not described herein again.

Those of ordinary skill in the art will appreciate that the steps of the various examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that for convenience and brevity of description, the specific working process of the method described above may refer to the corresponding process in the foregoing embodiment of the apparatus, and will not be described again here

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof.

When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the present application are all or partially generated upon loading and execution of computer program instructions on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. For example, the computer may be a personal computer, a server, or a network appliance, among others. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wirelessly (e.g., infrared, wireless, microwave, etc.). With regard to the computer-readable storage medium, reference may be made to the above description.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims and the specification.