阅读说明：本技术 一种基于gti的色散管理型光纤激光器 (Dispersion management type fiber laser based on GTI ) 是由 冯晓强 贾谞卓 宋园起 闫丽 林启蒙 侯磊 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种基于GTI的色散管理型光纤激光器,包括泵浦源、光纤器件和空间器件,所述的光纤器件包括波分复用器、增益光纤、聚焦器和光纤准直器,所述的空间器件包括设置在光纤准直器后侧且相互平行的第一GTI镜和第二GTI镜。采用GTI代替光栅对或者光纤布拉格光栅,GTI的反射率一般均可达到99.9％,在多次反射腔内激光提供更多的反常色散时,相比于光栅对能明显降低器件引入的插入损耗,提高激光器的输出效率；且GTI作为不易受环境变化影响的固体器件,相比于FBG可以提高激光器的环境稳定性。同时解决了现有技术中采用光栅对色散管理的掺镱光纤激光器输出效率不易继续提高以及采用FBG色散管理的掺镱光纤激光器环境稳定性不足的问题。(The invention discloses a dispersion management type fiber laser based on GTI, which comprises a pumping source, a fiber device and a space device, wherein the fiber device comprises a wavelength division multiplexer, a gain fiber, a focuser and a fiber collimator, and the space device comprises a first GTI mirror and a second GTI mirror which are arranged at the rear side of the fiber collimator and are parallel to each other. The GTI is adopted to replace a grating pair or a fiber Bragg grating, the reflectivity of the GTI can generally reach 99.9%, and when laser provides more anomalous dispersion in a multiple reflection cavity, compared with the grating pair, the insertion loss introduced by a device is obviously reduced, and the output efficiency of the laser is improved; and as a solid device which is not easily influenced by environmental changes, the GTI can improve the environmental stability of the laser compared with FBG. Meanwhile, the problems that the output efficiency of the ytterbium-doped fiber laser adopting optical grating to dispersion management is not easy to be continuously improved and the environmental stability of the ytterbium-doped fiber laser adopting FBG dispersion management is not enough in the prior art are solved.)

1. A dispersion management type fiber laser based on GTI, comprising a pump source (1), a fiber device (2) and a space device (3), wherein the fiber device (2) comprises a wavelength division multiplexer (201), a gain fiber (202), a focalizer (203) and a fiber collimator (204), and is characterized in that the space device (3) comprises a first GTI mirror (301) and a second GTI mirror (302) which are arranged at the rear side of the fiber collimator (204) and are parallel to each other, a high-reflection mirror (304) arranged at the rear side of the second GTI mirror (302), and a semiconductor saturable absorber mirror (305) arranged at the front side of the focalizer (203);

the first GTI mirror (301) and the second GTI mirror (302) are obliquely arranged relative to the emergent laser of the laser, and the emergent laser is incident on the second GTI mirror (302).

2. A GTI-based dispersion managed fiber laser according to claim 1 wherein said spatial device (3) further comprises a variable optical attenuator (303) disposed between the fiber collimator (204) and the first GTI mirror (301).

3. The GTI-based dispersion managed fiber laser of claim 2 wherein said variable optical attenuator (303) comprises a half wave plate (30301) and a polarizing beam splitter (30302).

4. The GTI-based dispersion managed fiber laser according to claim 1, wherein the pump end (20101) of the wavelength division multiplexer (201) is connected to the pump source (1), the signal optical end (20102) of the wavelength division multiplexer (201) is connected to the fiber collimator (204), the common end (20103) of the wavelength division multiplexer (201) is connected to one end of the gain fiber (202), and the other end of the gain fiber (202) is connected to the focuser (203).

5. The GTI-based dispersion managed fiber laser of claim 1, wherein the pump laser of the pump source (1) has an output wavelength of 976nm and an output power in the range of 0-500 mW.

6. The GTI-based dispersion managed fiber laser of claim 1 wherein said gain fiber (202) is a polarization maintaining ytterbium ion doped gain fiber.

7. The GTI-based dispersion managed fiber laser of claim 1 wherein said wavelength division multiplexer (201) operates over a wavelength range of 980 + 10nm/1030 + 25 nm.

8. The GTI-based dispersion managed fiber laser of claim 1 wherein said highly reflective mirror (304) has an operating wavelength band of 750nm to 1100 nm.

9. The GTI-based dispersion managed fiber laser of claim 1 wherein said high reflectivity mirror (304) has a reflectivity greater than 99%.

10. The GTI-based dispersion managed fiber laser of claim 1, wherein the pump source (1), the wavelength division multiplexer (201), the focuser (203) and the pigtail of the fiber collimator (204) are all polarization maintaining fibers.

Technical Field

The invention belongs to the technical field of ultrafast optical fiber lasers, relates to an optical fiber laser, and particularly relates to a dispersion management type optical fiber laser based on GTI.

Background

In ytterbium-doped fiber lasers, the normal fiber can only provide normal dispersion, and if dispersion management is required, pairs of gratings or anomalous dispersion Fiber Bragg Gratings (FBGs) are typically used to provide anomalous dispersion to control the net dispersion in the cavity, thereby achieving narrower pulses and wider spectral output. However, both of these methods have inherent disadvantages. The grating pair compensates the dispersion by the principle of diffracting light of different frequencies in the light pulse to make them generate optical path difference, and the diffraction efficiency is considerable (up to 90%), but when multiple reflections provide more anomalous dispersion, the efficiency is reduced suddenly, so that more intracavity loss is introduced, which is not favorable for obtaining high power output. In the method of compensating dispersion by FBG, since the FBG gate region is very sensitive to external temperature and external stress, the laser adopting FBG to compensate dispersion is easily affected by external environment change and loses mode-locking state.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a dispersion management type fiber laser based on GTI (GTI), and solve the problems that the output power of an ytterbium-doped mode-locked fiber laser adopting grating dispersion management in the prior art is difficult to be continuously improved and the environmental stability of the ytterbium-doped mode-locked fiber laser adopting FBG dispersion management in the prior art is poor.

In order to solve the technical problems, the invention adopts the following technical scheme:

a dispersion management type fiber laser based on GTI comprises a pumping source, a fiber device and a space device, wherein the fiber device comprises a wavelength division multiplexer, a gain fiber, a focalizer and a fiber collimator, the space device comprises a first GTI mirror and a second GTI mirror which are arranged at the rear side of the fiber collimator and are parallel to each other, a high-reflection mirror arranged at the rear side of the second GTI mirror, and a semiconductor saturable absorption mirror arranged at the front side of the focalizer;

the first GTI mirror and the second GTI mirror are obliquely arranged relative to the emergent laser of the laser, and the emergent laser is incident on the second GTI mirror.

The invention also comprises the following technical features:

the space device also comprises an adjustable optical attenuator arranged between the optical fiber collimator and the first GTI mirror.

The adjustable optical attenuator comprises a half-wave plate and a polarization beam splitter.

The pump end of the wavelength division multiplexer is connected with the pump source, the signal light end of the wavelength division multiplexer is connected with the optical fiber collimator, the common end of the wavelength division multiplexer is connected with one end of the gain optical fiber, and the other end of the gain optical fiber is connected with the focalizer.

The output wavelength of the pump laser of the pump source is 976nm, and the output power range is 0-500 mW.

The gain fiber is a polarization-maintaining ytterbium-doped ion gain fiber.

The working wavelength range of the wavelength division multiplexer is 980 +/-10 nm/1030 +/-25 nm.

The working wave band of the high-reflection mirror is 750 nm-1100 nm.

The reflectivity of the high-reflection mirror is more than 99%.

The tail fibers of the pumping source, the wavelength division multiplexer, the focuser and the optical fiber collimator are all polarization maintaining fibers.

Compared with the prior art, the invention has the beneficial technical effects that:

in the invention, GTI is adopted to replace a grating pair or a fiber Bragg grating, and as the reflectivity of GTI generally can reach 99.9%, when laser provides more anomalous dispersion in a multiple reflection cavity, compared with the grating pair, the insertion loss introduced by a device is obviously reduced, and the output efficiency of the laser is improved; and as a solid device which is not easily influenced by environmental changes, the GTI can improve the environmental stability of the laser compared with FBG. Meanwhile, the technical problems that the output efficiency of the ytterbium-doped fiber laser adopting optical grating to dispersion management is not easy to be continuously improved and the environmental stability of the ytterbium-doped fiber laser adopting FBG dispersion management is not enough in the prior art are solved.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a spectral plot of a dispersion managed soliton pulse of an embodiment of the present invention;

FIG. 3 is a schematic diagram of a dispersion managed soliton single pulse width signal of an embodiment of the present invention;

the meaning of the individual reference symbols in the figures is: 1-a pumping source, 2-an optical fiber device and 3-a space device;

201-wavelength division multiplexer, 202-gain fiber, 203-focalizer, 204-fiber collimator;

20101-a pumping end, 20102-a signal light end and 20103-a public end;

301-a first GTI mirror, 302-a second GTI mirror, 303-a variable optical attenuator, 304-a high-reflection mirror, 305-a semiconductor saturable absorber mirror;

30301-half wave plate, 30302-polarizing beam splitter.

The present invention will be explained in further detail with reference to examples.

Detailed Description

It should be noted that the GTI is generally known as a Gires-Tournois interferometer and is generally translated into a Giless-Turnwa interferometer.

All parts in the present invention are those known in the art, unless otherwise specified.

The following embodiments of the present invention are provided, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are within the protection scope of the present invention.

The dispersion management type fiber laser based on GTI provided by the invention comprises a pumping source 1, a fiber device 2 and a space device 3, wherein the fiber device 2 comprises a wavelength division multiplexer 201, a gain fiber 202, a focuser 203 and a fiber collimator 204, the space device 3 comprises a first GTI mirror 301 and a second GTI mirror 302 which are arranged at the rear side of the fiber collimator 204 and are parallel to each other, a high reflection mirror 304 arranged at the rear side of the second GTI mirror 302 and a semiconductor saturable absorber mirror 305 arranged at the front side of the focuser 203;

the first GTI mirror 301 and the second GTI mirror 302 are disposed to be inclined with respect to the emitted laser beam of the laser, and the emitted laser beam is incident on the second GTI mirror 302.

In the above technical solution, after passing through the wavelength division multiplexer 201 and the gain fiber 202, the laser emitted from the pump source 1 is collimated by the focalizer 203 and output as space light to be incident on the semiconductor saturable absorber mirror 305, the semiconductor saturable absorber mirror 305 modulates the incident light, and then reflects the light to return to the original path, and the light enters the focalizer 203, the gain fiber 202 and the wavelength division multiplexer 201 in sequence, and then is output to the fiber collimator 204 by the wavelength division multiplexer 201, and is collimated by the fiber collimator 204 into space light to enter the space device 3, enters the first GTI mirror 301 and the second GTI mirror 302, and after being reflected for several times between the first GTI mirror 301 and the second GTI mirror 302, the light vertically enters the high reflection mirror 304, and returns to the semiconductor saturable absorber mirror 305 again, and after a stable resonant cavity is formed between the semiconductor saturable absorber mirror 305 and the high reflection mirror 304, when the laser in the laser cavity is in a round-trip resonant mode, each time the laser is reflected on the GTI mirror, a certain amount of anomalous dispersion can be compensated, so that different anomalous dispersions can be compensated by adjusting the reflection times of the laser in the cavity between a pair of GTI mirrors, lasers with different parameters can be output, and the pulse width parameter of the output laser spectrum can be adjusted. Finally, the output of the polarization beam splitter 30302 is measured at its output port using a spectrometer and autocorrelator.

In the technical scheme, the GTI is adopted to replace a grating pair or a fiber Bragg grating, and as the reflectivity of the GTI generally can reach 99.9%, when laser provides more anomalous dispersion in a multiple reflection cavity, the insertion loss introduced by a device is obviously reduced compared with the grating pair, and the output efficiency of the laser is improved; and as a solid device which is not easily influenced by environmental changes, the GTI can improve the environmental stability of the laser compared with FBG. The technical problem that the output efficiency of an ytterbium-doped fiber laser adopting optical grating to dispersion management is not easy to be continuously improved and the technical problem that the environmental stability of the ytterbium-doped fiber laser adopting FBG dispersion management is not enough in the prior art are solved.

As a preferred aspect of the present invention, the space device 3 further includes an adjustable optical attenuator 303 disposed between the fiber collimator 204 and the first GTI mirror 301.

Specifically, the adjustable optical attenuator 303 includes a half-wave plate 30301 and a polarization beam splitter 30302, and the optical power output from the output end of the polarization beam splitter is adjusted by rotating the half-wave plate; the polarization beam splitter is used for splitting incident light into two mutually vertical linearly polarized light beams, one beam continuously oscillates and amplifies in the cavity, and the other beam is output to the outside of the cavity.

As a preferred scheme of the present invention, the pump end 20101 of the wavelength division multiplexer 201 is connected to the pump source 1, the signal light end 20102 of the wavelength division multiplexer 201 is connected to the optical fiber collimator 204, the common end 20103 of the wavelength division multiplexer 201 is connected to one end of the gain fiber 202, and the other end of the gain fiber 202 is connected to the focalizer 203.

Specifically, the output wavelength of the pump laser of the pump source 1 is 976nm, and the output power range is 0-500 mW.

Specifically, the gain fiber 202 is a polarization-maintaining ytterbium-doped ion gain fiber.

Specifically, the wavelength division multiplexer 201 operates in the wavelength range of 980 ± 10nm/1030 ± 25 nm.

Specifically, the working waveband of the high-reflection mirror 304 is 750nm to 1100 nm.

In a preferred embodiment of the present invention, the high-reflectivity mirror 304 has a reflectivity greater than 99%, ensuring that substantially all of the incident light is reflected.

As a preferred scheme of the invention, the tail fibers of the pumping source 1, the wavelength division multiplexer 201, the focalizer 203 and the optical fiber collimator 204 are all polarization-maintaining fibers, and the tail fibers adopt the polarization-maintaining fibers, so that space devices can be fixed, and the space devices have better stability.

Example (b):

the embodiment provides a dispersion management type fiber laser based on GTI, which comprises a pumping source 1, a fiber device 2 and a space device 3, wherein the fiber device 2 comprises a wavelength division multiplexer 201, a gain fiber 202, a focuser 203 and a fiber collimator 204, the space device 3 comprises a first GTI mirror 301 and a second GTI mirror 302 which are arranged at the rear side of the fiber collimator 204 and are parallel to each other, a high-reflection mirror 304 arranged at the rear side of the second GTI mirror 302, and a semiconductor saturable absorption mirror 305 arranged at the front side of the focuser 203;

the first GTI mirror 301 and the second GTI mirror 302 are disposed obliquely with respect to the emitted laser light of the laser, and the emitted laser light is incident on the second GTI mirror 302.

The spatial device 3 further comprises an adjustable optical attenuator 303 arranged between the fibre collimator 204 and the first GTI mirror 301.

The adjustable optical attenuator 303 includes a half-wave plate 30301 and a polarization beam splitter 30302.

The pumping end 20101 of the wavelength division multiplexer 201 is connected with the pumping source 1, the signal light end 20102 of the wavelength division multiplexer 201 is connected with the optical fiber collimator 204, the common end 20103 of the wavelength division multiplexer 201 is connected with one end of the gain optical fiber 202, and the other end of the gain optical fiber 202 is connected with the focalizer 203.

The output wavelength of the pumping laser of the pumping source 1 is 976nm, and the output power range is 0-500 mW.

The gain fiber 202 is a polarization maintaining ytterbium-doped ion gain fiber.

The wavelength division multiplexer 201 has a pump end working wavelength of 980nm and a common end and signal light end working wavelength of 1030 nm.

The working wave band of the high reflecting mirror 304 is 750 nm-1100 nm.

The reflectance of the high reflectance mirror 304 is 99.5%.

The pigtails of the pump source 1, the wavelength division multiplexer 201, the focuser 203 and the fiber collimator 204 are all polarization maintaining fibers.

Using the laser of this example, a spectral plot of the dispersion managed soliton pulse shown in fig. 2 and a dispersion managed soliton single pulse width signal plot shown in fig. 3 were obtained. As can be seen from fig. 2, the full width at half maximum of the output spectrum of the laser is 15.51nm, the center wavelength of the spectrum is around 1030nm, and theoretically, the hyperbolic secant fourier transform pulse width corresponding to the spectrum is about 72 fs; as can be seen from fig. 3, the laser output pulse width measured by the autocorrelator is actually 78fs under the condition of hyperbolic secant fitting, and the measured pulse width is already close to the fourier-limit transform pulse width value corresponding to the theoretical output spectrum, which indicates that the GTI has compensated the appropriate anomalous dispersion at this time, the whole laser works in a near-zero dispersion region, the chirp content in the output pulse is close to zero, and the excellent dispersion compensation performance of the GTI is also proved.