CN212162326U

CN212162326U - Optical fiber coupling system

Info

Publication number: CN212162326U
Application number: CN202020839011.XU
Authority: CN
Inventors: 谢刚; 虞华康
Original assignee: Hangzhou Yiquan Photoelectric Co ltd
Current assignee: Hangzhou Yiquan Photoelectric Co ltd
Priority date: 2020-05-19
Filing date: 2020-05-19
Publication date: 2020-12-15
Anticipated expiration: 2030-05-19

Abstract

The utility model relates to an optical fiber coupling system, which comprises a laser, an aspheric lens, a first cylindrical lens (1), a second cylindrical lens (2), a coupling lens and optical fibers which are arranged in sequence; laser emitted by the laser device is subjected to fast axis collimation through the aspheric lens, then sequentially passes through the first cylindrical lens (1) and the second cylindrical lens (2) to be subjected to fast axis spot compression, and then is focused through the coupling lens to enter the optical fiber. The utility model discloses an optical fiber coupling system has avoided using the fast axle collimating lens of expensive aspheric surface, and the cost is reduced has higher coupling efficiency.

Description

Optical fiber coupling system

Technical Field

The utility model relates to a laser technical field especially relates to an optical fiber coupling system.

Background

Coupling laser light into an optical fiber is a widely used technique. For example, the well-known optical fiber communication is that laser is coupled into an optical fiber for long-distance transmission communication. The solid-state laser beam is relatively easy to couple into the optical fiber because of its good quality. However, semiconductor lasers have serious astigmatism due to their intrinsic characteristics, and have large differences in beam quality and divergence angle between the fast axis and the slow axis, and thus require special optical design for efficient coupling to optical fibers.

Traditionally, there are a number of ways to couple semiconductor lasers into optical fibers:

1. the optical fiber rancour is directly arranged near the light emitting point of the semiconductor laser, the structure is very simple and compact, but the coupling efficiency is generally not more than 50%;

2. on the basis of 1, the coupling efficiency can be improved to 60-70% by a micro lens or by grinding the end face of the optical fiber into a micro spherical surface or a double wedge surface;

3. the high-power system uses a micro-lens array or an aspheric cylindrical lens (a fast axis collimating lens) for collimation, and then is matched with light path designs such as a step lens and the like, so that higher efficiency (more than 80%) can be obtained.

4. For a single-point semiconductor laser, a method of 'fast axis collimating lens + slow axis collimating lens + aspheric coupling lens' is used, so that the coupling efficiency can be more than 80%.

The methods 1 and 2 are suitable for coupling the small-power laser to the small-core optical fiber. Although the coupling efficiency is not high, the coupling efficiency is greatly used in optical fiber communication or low-power laser coupling due to the large market size, low laser cost and simple and compact structure and easy production.

The 3 rd method is suitable for coupling high-power laser to optical fiber with larger core diameter. Although the price of the devices such as the micro-lens array, the fast axis collimating mirror, the step mirror and the like is not good, the application scene of the device is mainly oriented to a high-power laser system, and the whole system is very expensive, so that the device is not sensitive to the cost of individual devices.

However, in some special applications, such as long-range laser illumination, the coupling efficiency is sensitive to the overall system cost because semiconductor lasers are relatively expensive. Also, due to the long transmission distances, it is desirable to minimize the core diameter of the fiber to reduce the cost of the fiber. Technically, the method 4 is the simplest method, but the fast axis collimator lens is an aspherical cylindrical lens, which is very costly. Therefore, it is necessary to efficiently couple a semiconductor laser of high power into an optical fiber of a small core diameter for transmission and to reduce the cost as much as possible.

SUMMERY OF THE UTILITY MODEL

The utility model discloses to the problem that prior art exists, a fiber coupling system design is proposed.

The utility model discloses a can realize through following technical scheme:

the utility model provides an optical fiber coupling system, including laser instrument, aspheric lens, first cylindrical mirror 1, second cylindrical mirror 2, coupling lens, optic fibre that set gradually; laser emitted by the laser device is subjected to fast axis collimation through the aspheric lens, then sequentially passes through the first cylindrical lens 1 and the second cylindrical lens 2 to be subjected to fast axis spot compression, and then enters the optical fiber through the coupling lens in a focusing mode.

Preferably, the laser is a semiconductor laser emitting light in a single point or a double point; and when the laser emits light in double points, the total length of the light emitting area is not more than 300 mu m.

Preferably, the aspheric lens has a plano-convex structure or a biconvex structure, and at least one convex surface is an odd-order aspheric surface or an even-order aspheric surface.

Preferably, the aspheric lens has an effective focal length of 1.5mm to 12 mm.

Preferably, the laser light-emitting point is arranged on the focal plane of the aspheric lens, and the collimated laser fast axis far field divergence angle is smaller than 1 °.

Preferably, the aspheric lens is integrally packaged with the laser or is independently arranged outside the laser packaging structure.

Preferably, the first cylindrical lens 1 is a plano-convex cylindrical lens or a biconvex cylindrical lens, and the refractive direction of the convex cylindrical surface is set in the fast axis direction of the laser.

Preferably, the effective focal length of the first cylindrical mirror 1 is 8mm to 50 mm.

Preferably, the second cylindrical lens 2 is a plano-concave cylindrical lens or a biconcave cylindrical lens, and the concave cylindrical diopter direction is set in the fast axis direction of the laser.

Preferably, the effective focal length of the second cylindrical lens 2 is from-2 mm to-10 mm.

Preferably, the coupling lens is of a plano-convex structure or a biconvex structure, and at least one convex surface is an odd-order aspheric surface or an even-order aspheric surface; when the coupling lens is of a plano-convex structure, the sequence of laser passing is as follows: first passing through the aspheric convex surface and then passing through the plane.

Preferably, the optical fiber is a quartz optical fiber with a core diameter of 20-400 μm, and is located at a focus of the laser light converged by the coupling lens.

Preferably, the aspheric lens, the first cylindrical lens 1, the second cylindrical lens 2, and the coupling lens are made of optical glass or quartz.

Preferably, the laser has a light emitting area length l and a fast axis divergence angle theta_{Fast-acting toy}Slow axis divergence angle theta_SlowThe divergence angles are all half angles, the core diameter d and the numerical aperture NA of the optical fiber, and the focal length f of the aspheric lens₁Focal length f of the coupling lens₂Focal length f of the first cylindrical mirror 1_{Column 1}And the focal length f of the second cylindrical lens 2_{Column 2}Satisfies the relationship:

the utility model discloses following beneficial effect has.

1. The optical fiber coupling system of the utility model avoids using expensive aspheric surface fast axis collimating lens, and reduces the cost; 2. The utility model discloses an optical fiber coupling system can advance optic fibre with the laser efficient coupling of semiconductor laser output, realizes the efficiency more than 80%.

Drawings

Fig. 1 is the structure diagram of the laser fiber coupling system of the present invention.

Fig. 2 is the optical path schematic diagram of the optical fiber coupling system of the present invention.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

Example 1

The optical fiber coupling system comprises a laser 1, an aspheric lens 2, a first cylindrical lens 3, a second cylindrical lens 4, a coupling lens 5 and an optical fiber 6 which are arranged in sequence; laser emitted by the laser 1 is subjected to fast axis collimation through the aspheric lens 2, then sequentially passes through the first cylindrical lens 33 and the second cylindrical lens 4 to be subjected to fast axis spot compression, and then is focused through the coupling lens 5 to enter the optical fiber 6.

The laser is a single-point light-emitting semiconductor laser, the length of a light-emitting area is 75um, and the output power is 2W; the aspheric lens is a plano-convex aspheric surface, and the focal length is 4 mm; the focal length of the first cylindrical lens 1 is 20mm, and the refraction direction is arranged in the slow axis direction of the laser; 2mm of focal length of the second cylindrical lens, and the refraction direction is arranged in the slow axis direction of the laser; the focal length of the coupling lens is 4 mm; the diameter of the quartz optical fiber core is 100 μm. After debugging, the optical fiber is coupled and output 1.7W, and the coupling efficiency is 85 percent.

It will be understood by those skilled in the art that the embodiments of the present invention as described above and shown in the drawings are given by way of example only and are not limiting of the present invention. The purpose of the utility model is completely and effectively realized. The functional and structural principles of the present invention have been shown and described in the embodiments without departing from the principles, embodiments of the present invention may have any deformation or modification.

Claims

1. An optical fiber coupling system is characterized by comprising a laser, an aspheric lens, a first cylindrical lens, a second cylindrical lens, a coupling lens and an optical fiber which are arranged in sequence; laser emitted by the laser device is subjected to fast axis collimation through the aspheric lens, then sequentially passes through the first cylindrical lens and the second cylindrical lens to be subjected to fast axis light spot compression, and then is focused through the coupling lens to enter the optical fiber.

2. The fiber coupling system of claim 1, wherein the laser is a single-point or dual-point emitting semiconductor laser; and when the laser emits light in double points, the total length of the light emitting area is not more than 300 mu m.

3. The fiber coupling system of claim 1, wherein the aspheric lens has a plano-convex or biconvex structure and at least one convex surface is an odd-order aspheric surface or an even-order aspheric surface.

4. The fiber coupling system of claim 1, wherein the aspheric lens has an effective focal length of 1.5mm-12 mm; the effective focal length of the first cylindrical mirror is 8mm to 50 mm; the effective focal length of the second cylindrical lens is-2 mm to-10 mm.

5. The fiber coupling system of claim 1, wherein the laser light emitting point is disposed on the focal plane of the aspheric lens such that the collimated laser light has a fast-axis far-field divergence of less than 1 °.

6. The fiber coupling system of claim 1, wherein the aspheric lens is integrally packaged with the laser or is separately disposed outside a laser package structure; the optical fiber is a quartz optical fiber with the core diameter of 20-400 μm and is positioned on a focus of the laser converged by the coupling lens; the aspheric lens, the first cylindrical lens, the second cylindrical lens and the coupling lens are made of optical glass materials or quartz materials.

7. The fiber coupling system of claim 1, wherein the first cylindrical lens is a plano-convex cylindrical lens or a biconvex cylindrical lens, and the convex cylindrical refraction direction is arranged in the fast axis direction of the laser.

8. The fiber coupling system of claim 1, wherein the second cylindrical lens is a plano-concave cylindrical lens or a biconcave cylindrical lens, and the concave cylindrical refraction direction is set in the fast axis direction of the laser.

9. The fiber coupling system of claim 1, wherein the coupling lens is of a plano-convex or biconvex structure, and at least one convex surface is an odd-order aspheric surface or an even-order aspheric surface; when the coupling lens is of a plano-convex structure, the sequence of laser passing is as follows: first passing through the aspheric convex surface and then passing through the plane.

10. The fiber coupling system of claim 1, wherein a light emitting region length of the laserlFast axis divergence angleθ _{Fast-acting toy}Slow axis divergence angleθ _SlowAll the divergence angles are half angles, and the core diameter of the optical fiberdAnd numerical apertureNAFocal length of the aspherical lensf ₁Focal length of the coupling lensf ₂A focal length of the first cylindrical mirrorf _{Column 1}And the focal length of the second cylindrical lensf _{Column 2}Satisfies the relationship:

。