阅读说明：本技术 新型多芯光纤耦合装置及制备方法 (Novel multi-core optical fiber coupling device and preparation method ) 是由 贾大功 王绮 李明威 张红霞 杨传浩 于 2021-08-19 设计创作，主要内容包括：本发明公开了一种新型多芯光纤耦合装置及制备方法,包括输入多芯光纤(1)和输出多芯光纤(3),其中：所述输入多芯光纤(1)和所述输出多芯光纤(3)耦合对准,所述输入多芯光纤(1)和所述输出多芯光纤(3)之间设置耦合件(2),所述耦合件(2)的两端通过光学胶(7)分别与述输入多芯光纤(1)和所述输出多芯光纤(3)相连接；所述耦合件(2)为近似圆台结构,所述耦合件(2)内部设置多个通孔(33),在通孔(33)内部加入折射率匹配液(5),保证光的正常传输。与现有技术相比,本发明实现多芯光纤之间信号传输,结构简单,耦合方便并且效率高。(The invention discloses a novel multi-core fiber coupling device and a preparation method thereof, wherein the novel multi-core fiber coupling device comprises an input multi-core fiber (1) and an output multi-core fiber (3), wherein: the input multi-core fiber (1) and the output multi-core fiber (3) are coupled and aligned, a coupling piece (2) is arranged between the input multi-core fiber (1) and the output multi-core fiber (3), and two ends of the coupling piece (2) are respectively connected with the input multi-core fiber (1) and the output multi-core fiber (3) through optical cement (7); coupling piece (2) are approximate round platform structure, coupling piece (2) inside sets up a plurality of through-holes (33), adds refracting index matching fluid (5) inside through-hole (33), guarantees the normal transmission of light. Compared with the prior art, the multi-core fiber coupling device realizes signal transmission among the multi-core fibers, and has the advantages of simple structure, convenience in coupling and high efficiency.)

1. A novel multi-core fiber coupling device, characterized in that the device comprises an input multi-core fiber (1) and an output multi-core fiber (3), wherein:

the input multi-core fiber (1) and the output multi-core fiber (3) are coupled and aligned, a coupling piece (2) is arranged between the input multi-core fiber (1) and the output multi-core fiber (3), and two ends of the coupling piece (2) are respectively connected with the input multi-core fiber (1) and the output multi-core fiber (3) through optical cement (7);

a plurality of through holes (33) are formed in the coupling piece (2) and are placed between the two optical fibers for coupling;

and the refractive index matching fluid (5) is added into the through hole (33) to ensure the normal transmission of light.

2. A novel multicore fiber coupling device according to claim 1, wherein the input multicore fiber (1) and the output multicore fiber (3) respectively employ multicore fibers of two different cladding diameters, core diameters, and core distances; the input multi-core fiber (1) is provided with a plurality of fiber cores (4) of the input multi-core fiber, and the output multi-core fiber (2) is provided with a plurality of fiber cores (6) of the output multi-core fiber.

3. A novel multicore optical fiber coupling device according to claim 1, wherein the coupling piece (2) is of an approximately truncated cone structure, the through hole (33) is a tapered through hole, and further comprises a small aperture end (8) and a large aperture end (9); the diameters of a small-aperture end (8) and a large-aperture end (9) at the two ends of the conical through hole are respectively the same as the diameters of the fiber cores (4) of the input multi-core fiber and the fiber cores (6) of the output multi-core fiber, and the distribution of the conical through hole is set according to the distribution intervals of the fiber cores (4) of the input multi-core fiber and the fiber cores (6) of the output multi-core fiber.

4. A novel multi-core fiber coupling device as claimed in claim 1, wherein the input multi-core fiber (1) and the output multi-core fiber (3) are the same type of multi-core fiber.

5. A novel multicore optical fiber coupling device according to claim 4, wherein the coupling piece (2) is cylindrical and the through hole (33) is a circular through hole.

6. A novel multicore optical fiber coupling device according to claim 1, wherein the coupling piece (2) further comprises an input end face near one side of the input multicore optical fiber (1) and an input end face near one side of the output multicore optical fiber (3); the hole diameter and the pitch of the input end face are the same as the diameter and the pitch of the fiber core (4) of the input multi-core fiber, and the structure of the output end face is the same as the internal structure of the fiber core (6) of the output multi-core fiber.

7. A novel multicore optical fiber coupling device according to claim 1, wherein the coupling piece (2) is provided with a marker structure (10) on one side.

8. The method for preparing a novel multi-core optical fiber coupling device as claimed in claim 1, wherein the method comprises the following steps:

firstly, observing end faces of an input multi-core fiber (1) and an output multi-core fiber (3) by using a microscope, respectively fixing the multi-core fibers on an adjusting frame, and aligning the fibers;

then, placing a coupling piece (2) between two input multi-core fibers (1) and the output multi-core fibers (3), using a convex structure (10) as a mark, placing the coupling piece (2) according to a required angle, then moving an adjusting frame fixed with the input multi-core fibers (1) and the output multi-core fibers (3) for alignment, processing a plurality of through holes (33) in the optical fiber coupling piece (2), wherein the sizes of any input hole and any output hole of the through holes (33) are different from the center distance of a circle; the through hole (33) of the coupling piece (2) is filled with refractive index matching fluid to form a solid-liquid microfluid optical waveguide structure; the coupling piece (2) is placed between the two multi-core optical fibers to ensure the continuous transmission of optical signals; the optical signal to be transmitted is incident into the connecting piece from the multi-core optical fiber at one side, and the optical signal is transmitted into the multi-core optical fiber at the other side through the inside of the connecting piece, so that the coupling of the signal is completed;

and finally, coating optical cement (7) on the two ends of the coupling piece (2) by using a glue dispensing needle for fixing, and completing the connection of two different multi-core fibers, namely the input multi-core fiber (1) and the output multi-core fiber (3).

Technical Field

The invention relates to the technical field of optical fiber coupling, in particular to a novel multi-core optical fiber coupling device.

Background

Since the multi-core optical fiber has a plurality of channels, a large amount of information is transmitted along different channels, which is an important transmission medium for future optical communication. The research on the multi-core optical fiber is increasing, and the specification types of the multi-core optical fiber are also increasing. For multi-core optical fibers with different specifications, the coupling of the optical fibers is difficult due to the different sizes of the inner diameter and the outer diameter. The commonly used methods for optical fiber coupling mainly include a tapering method, a lens coupling method and a polymer waveguide method.

U.S. Pat. No. US20140119694, technique and Devices For Low-loss coupling Fiber, discloses an optical Fiber coupler with a tapered Fiber bundle, in which a plurality of single-mode fibers are arranged according to the core diameter spacing of a multi-core Fiber to form a tapered Fiber bundle, the diameter of the tapered Fiber bundle at the tapered end is the same as that of a conventional multi-core Fiber, and matching of the core spacing and the mode field diameter is realized between a plurality of input fibers and each core of the multi-core Fiber.

U.S. patent No. US10234632, Connectors For Multicore Optical Fibers And Methods Thereof, discloses a connector For Multicore Optical Fibers. The coupling between the multi-core fiber and the multi-core fiber or other optical devices is realized by changing the size and the shape of the lens and the arrangement of the micro-lens array. However, the method mainly utilizes the lens group to perform the spatial coupling of light, which is not beneficial to subsequent packaging and movement and has the defect of complex coupling mechanism, and for multi-core optical fibers with different structures, the coupling form needs to be readjusted, the operation is difficult and the cost is high.

The invention discloses a preparation method of a multi-core fiber coupler, which is a Chinese invention patent with the publication number of CN111796361A, and the invention is mainly suitable for connection between multi-cladding fibers containing a plurality of claddings and non-multi-cladding fibers such as single-mode fibers, few-mode fibers and the like. After the non-multi-cladding optical fiber and the multi-cladding optical fiber are welded, the circular capillary tube which is heated and stretched is inserted, the conical waist area of the circular capillary tube is heated and stretched for the second time, then the conical waist area formed by secondary stretching is cut, the middleware containing the non-multi-cladding optical fiber and the multi-cladding optical fiber is obtained, and the cutting end of the middleware is welded with the multi-core optical fiber to realize the coupling of the multi-core optical fiber. The coupler has good expandability, but has complex operation and complex structure, and the multiple heating and stretching are not suitable for the optical fiber with the air hole, so that the collapse or the fracture of the air hole is easily caused, and the structure of the multi-core optical fiber is damaged.

Chinese patent publication No. CN105785511B, a method for manufacturing a multi-core fiber coupler based on tapered self-assembly, discloses that the present invention mainly uses the technique of tapered coupling to align and couple a fiber bundle composed of seven-core fibers and seven single-mode fibers. The method has the advantages of good expandability, high yield, simple process and simple operation, but is not suitable for coupling multi-core optical fibers with different fiber core arrangement structures, and the tapered structure can damage the optical fiber structure of the optical fiber with the air hole structure.

Chinese patent publication No. CN105204119A, a method for preparing a multicore fiber coupler based on micro-hole processing, discloses that the present invention uses mechanical drilling or laser drilling to process cylindrical holes in a cylindrical sleeve, wherein the cylindrical holes are arranged in the same way as the fiber cores of the multicore fibers, and single mode fibers are inserted into the micro-holes to form fiber bundles, the fiber bundles formed by the multicore fibers and the single mode fibers are placed in the micro-holes processed by the sleeve, and are fixed by uv glue or thermosetting glue, polished end faces by a polishing machine, aligned by a six-dimensional adjustment platform, fixed by uv glue through a glass sleeve, or aligned and welded by a welding machine, thereby completing the preparation of the multicore fiber coupler. However, the through hole processed in the cylindrical sleeve is mainly used for placing a single-mode optical fiber, and the method is mainly used for coupling between a multi-core optical fiber and a plurality of single-mode optical fibers, and the diameter of the through hole processed in the coupler is a fixed value, so that the use of the through hole is limited.

The above-mentioned several coupler preparation methods are mainly aimed at coupling two multi-core optical fibers with same specification, or between multi-core optical fiber and single-core optical fiber bundle with same arrangement, but are not applicable to optical fibers with different specifications, such as multi-core optical fiber with air hole, optical fiber with different cladding thickness, etc. Therefore, it is important to design a multi-core fiber coupler suitable for different specifications to realize the connection between the same or different types of optical fibers, and how to solve the technical problem

Disclosure of Invention

The invention aims to provide a novel multi-core optical fiber coupling device and a preparation method thereof, wherein the cold connection of two multi-core optical fibers is realized by using an optical waveguide coupling mode, and the obtained novel multi-core optical fiber coupling device realizes the connection between two multi-core optical fibers of different types.

The invention is realized by the following technical scheme:

a novel multi-core fiber coupling device, the device comprising an input multi-core fiber 1 and an output multi-core fiber 3, wherein:

the input multi-core fiber 1 and the output multi-core fiber 3 are coupled and aligned, a coupling piece 2 is arranged between the input multi-core fiber 1 and the output multi-core fiber 3, and two ends of the coupling piece 2 are respectively connected with the input multi-core fiber 1 and the output multi-core fiber 3 through optical cement 7;

a plurality of through holes 33 are formed in the coupling piece 2 and are placed between two optical fibers for coupling;

the refractive index matching fluid 5 is added into the through hole 33 to ensure the normal transmission of light.

The input multi-core fiber 1 and the output multi-core fiber 3 respectively adopt multi-core fibers with two different cladding diameters, fiber core diameters and fiber core distances; the input multicore fiber 1 has a plurality of cores 4 of input multicore fibers, and the output multicore fiber 2 has a plurality of cores 6 of output multicore fibers.

The coupling piece 2 is of an approximate circular truncated cone structure, and the through hole 33 is a conical through hole and further comprises a small-aperture end 8 and a large-aperture end 9; the diameters of the small-aperture end 8 and the large-aperture end 9 at the two ends of the tapered through holes are respectively the same as the diameters of the fiber cores 4 of the input multi-core fiber and the fiber cores 6 of the output multi-core fiber, and the distribution of the tapered through holes is set according to the distribution intervals of the fiber cores 4 of the input multi-core fiber and the fiber cores 6 of the output multi-core fiber.

The input multi-core fiber 1 and the output multi-core fiber 3 adopt the same multi-core fiber.

The coupling piece 2 is cylindrical, and the through hole 33 is a circular through hole.

The coupling element 2 further comprises an input end face close to one side of the input multi-core fiber 1 and an input end face close to one side of the output multi-core fiber 3; the hole diameter and pitch of the input end face are the same as the diameter and pitch of the core 4 of the input multicore fiber, and the structure of the output end face is the same as the internal structure of the core 6 of the output multicore fiber.

The coupling element 2 is provided with a marking structure 10 on one side.

A preparation method of a novel multi-core optical fiber coupling device comprises the following steps:

firstly, observing the end faces of an input multi-core fiber 1 and an output multi-core fiber 3 by using a microscope, respectively fixing the multi-core fibers on an adjusting frame, and aligning the fibers;

then, placing the coupling piece 2 between the two input multi-core fibers 1 and the output multi-core fiber 3, using the convex structure 10 as a mark, placing the coupling piece 2 according to a required angle, then moving an adjusting frame fixed with the input multi-core fibers 1 and the output multi-core fiber 3 for alignment, and processing a plurality of through holes 33 in the optical fiber coupling piece 2, wherein the sizes of any input hole and any output hole of the through holes 33 are different from the center distance; the through hole 33 of the coupling piece 2 is filled with refractive index matching fluid to form a solid-liquid microfluid optical waveguide structure; the coupling piece 2 is placed between two multi-core optical fibers to ensure the continuous transmission of optical signals; the optical signal to be transmitted is incident into the connecting piece from the multi-core optical fiber at one side, and the optical signal is transmitted into the multi-core optical fiber at the other side through the inside of the connecting piece, so that the coupling of the signal is completed;

and finally, coating optical cement 7 on the two ends of the coupling piece 2 by using a glue dispensing needle for fixing, and completing the connection of the input multi-core fiber 1 and the output multi-core fiber 3.

Compared with the prior art, the invention can achieve the following beneficial technical effects:

1) realizes signal transmission among the multi-core optical fibers, does not need secondary processing on the multi-core optical fibers, has simple structure, does not damage the optical fiber structure, is convenient to couple and high in efficiency, is convenient to move integrally, has strong adaptability,

2) the fiber coupling device is suitable for coupling between any two optical fibers with different fiber core layouts and different diameters or coupling between two optical fibers with the same fiber core layout and the same diameter, and has a wider application range.

Drawings

FIG. 1 is a schematic structural diagram of a novel multi-core fiber coupling device according to the present invention;

FIG. 2 is a schematic diagram of a coupling element;

FIG. 3 is a schematic diagram of an end face structure of a multi-core fiber (taking a seven-core as an example), (a) an input multi-core fiber; (b) an output multi-core fiber;

reference numerals:

1. the optical fiber coupling method comprises the steps of inputting a multi-core optical fiber, 2, a coupling piece, 3, outputting the multi-core optical fiber, 4, inputting a fiber core of the multi-core optical fiber, 5, a refractive index matching liquid, 6, outputting the fiber core of the multi-core optical fiber, 7, optical cement, 8, a small aperture end, 9, a large aperture end, 10, a mark structure, 11-17 and fiber cores, 18-24 are the fiber cores of common multi-core optical fibers, 25-31 are different fiber cores of the multi-core optical fiber with air holes, 32, the air holes, 33, through holes, 34 and a multi-core optical fiber cladding.

Detailed Description

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

As shown in fig. 1, the novel multicore fiber coupling device of the present invention includes an input multicore fiber 1 and an output multicore fiber 3, the input multicore fiber 1 and the output multicore fiber 3 are connected by a coupling element 2, the input multicore fiber 1 has a plurality of cores 4 of the input multicore fiber, and the output multicore fiber 2 has a plurality of cores 6 of the output multicore fiber. The input multi-core fiber 1 and the output multi-core fiber respectively adopt multi-core fibers with two different cladding diameters, fiber core diameters and fiber core distances or adopt the same kind of multi-core fibers. After the input multi-core fiber 1 and the output multi-core fiber 3 are coupled and aligned, the input multi-core fiber 1, the output multi-core fiber 3, and the coupling element 2 are connected by the optical cement 7.

As shown in fig. 2, a schematic diagram of a coupling element structure is shown. Firstly, when different multi-core fibers are coupled, the through hole 33 is the whole structure of the coupling piece 2 and is similar to a circular truncated cone, and the structure comprises an input end face close to one side of the input multi-core fiber 1 and an input end face close to one side of the output multi-core fiber 2; the hole diameter and the distance of the input end face need to be the same as the fiber core diameter and the distance of the input optical fiber, and the structure of the output end face needs to be the same as the internal structure of the output optical fiber in the same way. A plurality of through holes 33 are machined inside, the through holes 33 including a small aperture end 8 and a large aperture end 9. The diameters of the small aperture end 8 and the large aperture end 9 at both ends of the through hole 33 are respectively the same as the diameters of the cores 4 and 6 of the input multicore fiber and the output multicore fiber, and the distribution of the through hole 33 is set according to the distribution pitch of the cores 4 and 6 of the input multicore fiber and the output multicore fiber. The refractive index matching fluid 5 is added into the through hole 33 to ensure the normal transmission of light. On one side of the coupling element 2, a marking structure 10 is provided, which can be used for identification purposes, and which has a specific shape, such as a projection, a recess or a T-shaped table, to ensure that the arrangement of the internal holes is positioned for the subsequent alignment process when the connecting element is placed. In practical application, the size of the outer part of the coupling piece, the size and the position of the inner taper hole need to be specially designed according to the practical application multicore optical fiber. The refractive index matching fluid 5 is mainly used for filling through holes inside the coupling piece, and has the function of ensuring stable transmission of optical signals inside the coupling piece. The diameters and the distances of the small-aperture end 8 and the large-aperture end 9 which are positioned at the front end and the rear end of the tapered through hole are determined according to the cross-sectional view of the input-output multi-core optical fiber which needs to be coupled. And secondly, when the same multi-core optical fiber is coupled, the coupling piece 2 is changed into a cylindrical shape, the middle conical through hole is changed into a circular through hole, and the cylindrical through hole is placed between two optical fibers for coupling.

As shown in fig. 3, the end face structure of the multi-core fiber (seven cores for example) is schematically shown, and (a) is a schematic end face structure of the input multi-core fiber 1, including the cores 11 to 17. (b) For the schematic illustration of the two end face structures of the output multi-core fiber 3, the output multi-core fiber 3 may be different kinds of multi-core fibers (for example, the common multi-core fiber includes the cores 18 to 24 of the common multi-core fiber, or the multi-core fiber with air holes includes the cores 25 to 31 of the multi-core fiber with air holes and the multi-core fiber cladding 34), and the multi-core fiber has air holes 32 inside, and surrounds each core in a hexagonal shape to reduce crosstalk between the cores.

The internal structures, the fiber core diameters and the intervals of the input multi-core fiber and the output multi-core fiber are different, the two fibers cannot be directly coupled, the conventional coupling mode is not suitable, and meanwhile, when the multi-core fiber with the air hole is used, the internal structure of the fiber can be damaged by a tapering method, so that the coupling part is designed to realize the connection of the two multi-core fibers.

And (4) analyzing by using optical simulation software, and determining the length and the material of the connecting piece and the refractive index of the built-in matching fluid according to the lowest loss of the output optical fiber. Because the coupling piece 2 is a round platform structure, the structure 10 of a T-shaped platform is added on the side edge of the coupling piece, compared with other marks, the reference surface for installation and fixation can be provided, the reference surface can be stably placed on the adjusting frame, and when the optical fiber is coupled, subsequent adjustment and connection are facilitated.

The preparation method of the novel multi-core optical fiber coupling device comprises the following steps:

firstly, observing the end faces of an input multi-core fiber 1 and an output multi-core fiber 3 by using a microscope, respectively fixing the multi-core fiber on an adjusting frame at the angle, and aligning the fibers;

then placing a coupling piece 2 between the two input multi-core fibers 1 and the output multi-core fiber 3, using the convex structure 10 as a mark, placing the coupling piece 2 according to a required angle, and then moving an adjusting frame fixed with the input multi-core fibers 1 and the output multi-core fiber 3 for alignment, wherein a plurality of through holes are arranged inside the optical fiber coupling piece, and the size of the input and output holes of the conical through holes is different from the center distance of a circle; the through hole 33 of the coupling piece 2 is filled with refractive index matching fluid to form a solid-liquid microfluid optical waveguide structure; the coupling piece 2 is arranged between the two multi-core optical fibers to ensure the continuous transmission of optical signals; the optical signal to be transmitted is incident into the connecting piece from the multi-core optical fiber at one side, and the optical signal is transmitted into the multi-core optical fiber at the other side through the inside of the connecting piece, so that the coupling of the signal is completed; and finally, coating optical cement 7 at two ends of the coupling piece 2 by using a glue dispensing needle for fixing, and completing the connection of the input multi-core fiber 1 and the output multi-core fiber 3. In practical application, the coupling element needs to be designed according to the core diameter and the interval of two multi-core fibers to be connected.

The core of the connecting piece lies in that the position and the diameter of the through hole 33 are accurate, the position of the through hole 33 is ensured to be aligned with each corresponding fiber core of the multi-core optical fiber, meanwhile, the processing precision of two end planes is high, the end faces are smooth, and better connection with the optical fiber is ensured.

The optical fiber coupling method is mainly applied to the coupling of two multi-core optical fibers, a plurality of through holes are arranged inside the optical fiber coupling piece, and the sizes and the center distances of an input hole and an output hole of each through hole are different. When in use, the coupling piece is aligned with the multicore fibers at two sides, and then optical cement (ultraviolet or epoxy cement) is coated in a spot mode to fix the multicore fibers and the coupling piece, so that the connection of the two multicore fibers is realized. The optical adhesive adopted in the invention can be ultraviolet optical adhesive, optical epoxy adhesive, special optical adhesive and the like.

The multi-core optical fiber is selected from multi-core optical fibers with 2 cores or more, such as 3 cores, 7 cores, 19 cores and more, and is suitable for multi-core optical fibers with various different fiber core intervals and different internal structures.

For the same multi-core fiber coupling, the coupling piece 2 becomes a cylinder, the middle conical through hole becomes a circular through hole, and the coupling piece is placed between two fibers for coupling.

The above description is only a preferred embodiment of the present invention, and should not be construed as limiting the present invention. The technical solutions that are the same as (or substantially equivalent to) or substituted by the ideas of the present invention by those of ordinary skill in the art are within the scope of the present invention.