Optical fiber beam combiner

Abstract

The utility model relates to an optical fiber beam combiner. The device mainly comprises an input optical fiber 1 and an output bare fiber 2, one end of the input optical fiber 1 is provided with a fused biconical taper optical fiber bundle 3, and the input optical fiber 1 is connected with the output bare fiber 2 through the fused biconical taper optical fiber bundle 3; a first glass sleeve 4 is arranged on the input optical fiber 1, a tube shearing gap 100 is formed between the first glass sleeve 4 and the fused biconical taper optical fiber bundle 3, and a reflecting mirror 6 is arranged at one end, far away from the fused biconical taper optical fiber bundle 3, of the tube shearing gap 100; the output bare fiber 2 is provided with a pumping waste light filtering device 7 used for filtering out pumping waste light exceeding the outer cladding NA of the output bare fiber 2. According to the utility model, the heating problem of the high-power pumping beam combiner can be solved, and cladding light can be selectively filtered.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical communication technical field, especially a kind of optical fiber combiner. BACKGROUND

[0002] Compared with traditional solid-state laser, fiber laser has high conversion efficiency, good beam quality, convenient heat management and other advantages, and stable performance, and can be competent for various working environments; Based on its excellent performance, it has been widely used in industrial manufacturing, laser medical treatment, aerospace and national defense security and other fields, and promoted the development of various industries of society. With the continuous improvement of the requirement of fiber laser output power, high power also becomes one of the important development directions of fiber laser.

[0003] A key component in high-power fiber laser is pump signal fiber combiner, which directly determines the level of laser output power by bearing power. The basic principle of pump combiner is to realize beam coupling by directly using fusion after optical fiber taper shaping, and the end face pump structure fiber combiner is the mainstream way to realize high-power fiber laser at present, which has simple structure, high coupling efficiency and easy packaging.

[0004] The existing pump combiner generally uses multi-clad optical fiber as output fiber, and the multi-clad optical fiber uses polymer material with lower refractive index than clad material as surface coating layer, and the long-term tolerance temperature of the surface coating layer is generally only about 65℃. In the process of combing, due to the theoretical intrinsic loss of pump combiner and the defects of material and process, there must be light leakage phenomenon, and the light leakage will be partially converted into heat energy deposited on the coating layer of the multi-clad output fiber of the pump combiner, resulting in heating of the coating layer; In addition, the main process method of high-power pump combiner is sleeve method, and part of the back light will gather on the pipe mouth fixing glue, and the long-term tolerance temperature of the glue is only about 75℃, if you want to use it for a long time, you need to make the glue work in a reliable packaging temperature, and the heating of the glue and the optical fiber coating layer tends to be serious with the increase of power, which seriously limits the improvement of pump power and output power of fiber laser.

[0005] That is to say, the pipe mouth glue temperature and output fiber temperature of high-power pump combiner determine the combing power and performance of combiner.

[0006] The back reflection light of the combiner is transmitted to the tube opening glue through the combiner glass tube. The current mainstream solution is to cut the tube and laser etching. The tube cutting solution can directly cut off the back reflection light transmitted to the tube opening glue, which is very simple and effective. However, this method is a destructive operation, which is easy to splash debris, and the exit angle of the light from the front cut tube break is uncontrollable, which may still gather on the glue or fiber bundle to cause heating. Laser etching is to etch a channel on the glass tube by a carbon dioxide laser, so that the back reflection light leaks out in the form of scattered light, greatly reducing the situation that the back reflection light directly gathers on the glue to heat. However, this method is complex, and a small amount of light is still transmitted to the tube opening glue, and as the transmission power increases, the tube opening glue will still heat up.

[0007] Many combiners are designed and simulated according to the adiabatic tapering principle and the brightness conservation principle. The light beam can be completely transmitted from the fiber bundle to the output fiber with low loss. However, due to material defects and process limitations, a small amount of light will still leak to the coating layer to cause the coating layer to heat up. The current mainstream combiner cannot handle this part of the cladding light that leaks to the coating layer, and can only leave a margin through combiner design and strengthen the process to avoid the generation of this part of the cladding light, which greatly reduces the yield of the combiner. In addition, the production of the combiner is very strict in terms of raw materials and process production, requiring a small ellipticity of the capillary tube, few surface scars and scratches, high quality of the combiner tapering, small angle of the cut end face of the combiner product, smooth surface without burrs and fogging area, and small loss of the fusion of the product.

[0008] The existing cladding light processing is mainly achieved by destroying the total reflection condition of the cladding light transmission. One is to use high-refractive-index glue at the cladding points to refract the cladding light out. The high-refractive-index glue with a stepwise increase in refractive index at the cladding points, combined with heat dissipation packaging, can remove a large amount of cladding light. However, this method requires high control of the point gluing process and glue, and the glue is still prone to heating. Another method is to use the absorption characteristics of metal to remove the cladding light. Wrapping soft metal indium on the surface of the optical fiber can achieve this purpose. However, this solution relies on mechanical fixation and is easily affected by environmental temperature and humidity, which cannot be universally applied. The most commonly used method is the cladding light removal method based on scattering effect, which destroys the smooth surface of the optical fiber to scatter the cladding light at the cladding and air interface. Surface corrosion and laser microprocessing are commonly used to achieve this. The above solutions are used to remove all cladding light in the cladding. However, for combiners, we need to transmit light within the NA (NA refers to the numerical aperture of the optical fiber, which represents the ability of the optical fiber end face to receive light) of the output fiber cladding. Light greater than the output fiber cladding needs to be filtered out in advance.

[0009] Therefore, how to overcome the defects of the existing technology, how to solve the heating problem of high-power pumping combiner, and how to selectively filter out cladding light are urgent problems in this technical field. TECHNICAL SOLUTION

[0010] In view of the defects of the prior art or the improvement needs, how to solve the heating problem of the high-power pump combiner, and how to selectively filter the cladding light. The utility model provides a kind of optical fiber combiner, by optimizing the shearing pipe scheme, mirror is placed after shearing pipe fracture, can make the light that returns reflection and far away from combiner, not only solve the heating problem of pipe opening glue, also can avoid this part of light and hit on combiner to cause heating situation to occur;Simultaneously, an excess light filter device is added on output bare fiber, the device can selectively filter the cladding light, so that the light less than the outer cladding NA of output fiber continues to transmit, the light greater than the outer cladding NA of output fiber is filtered out in advance, so that it cannot reach coating, thereby reducing the temperature of output fiber coating.

[0011] The utility model adopts the following technical scheme:

[0012] First, the utility model provides a kind of optical fiber combiner, including input optical fiber 1 and output bare fiber 2, and one end of input optical fiber 1 is provided with fused taper fiber bundle 3, and input optical fiber 1 is connected with output bare fiber 2 by fused taper fiber bundle 3;First glass sleeve 4 is arranged on input optical fiber 1, and shearing pipe gap 100 is formed between first glass sleeve 4 and fused taper fiber bundle 3, and mirror 6 is arranged at the end of shearing pipe gap 100 far away from fused taper fiber bundle 3;Pump excess light filter device 7 for filtering the outer cladding NA of output bare fiber 2 is arranged on output bare fiber 2.

[0013] In some embodiments, the mirror 6 is arranged at the end of the shearing pipe gap 100 far away from the fused taper fiber bundle 3 by the adhesive sleeve 5; the adhesive sleeve 5 is sleeved and adhesively fixed on the first glass sleeve 4, and the mirror 6 is adhesively fixed at the end of the adhesive sleeve 5 facing the fused taper fiber bundle 3.

[0014] In some embodiments, the end face of the mirror 6 blocks the end of the shearing pipe gap 100 far away from the fused taper fiber bundle 3.

[0015] In some embodiments, the inner diameter of the adhesive sleeve 5 is greater than the outer diameter of the first glass sleeve 4, and the adhesive sleeve 5 is sleeved on the first glass sleeve 4 and fixed with the first glass sleeve 4 by dispensing.

[0016] In some embodiments, the cross-sectional area of the mirror 6 is greater than the cross-sectional area of the adhesive sleeve 5; the cross section of the mirror 6 is one of square, circular or any polygon.

[0017] In some embodiments, the mirror 6 is provided with a first through hole 601 in the middle, and the diameter of the first through hole 601 is consistent with the diameter of the input optical fiber 1.

[0018] In some embodiments, the mirror 6 is provided with a clamping opening 602, and the clamping opening 602 is in communication with the through hole 601.

[0019] In some embodiments, the pump waste light filtering device 7 comprises a second glass sleeve 701, and the second glass sleeve 701 is provided with a second through hole 702 in the middle, the diameter of the second through hole 702 is greater than the diameter of the output bare fiber 2, and the gap between the second through hole 702 and the output bare fiber 2 is filled with a medium 703 matched with the refractive index of the outer cladding of the output bare fiber 2, and the refractive index of the second glass sleeve 701 is higher than the refractive index of the medium 703.

[0020] In some embodiments, the outer side of the second glass sleeve 701 is subjected to roughening treatment.

[0021] In some embodiments, the output bare fiber 2 is provided with an output optical fiber coating layer 8 at one end away from the fused taper optical fiber bundle 3.

[0022] Compared with the prior art, the optical fiber combiner has the beneficial effects that: the mirror is placed at the pipe cutting fracture after the pipe cutting scheme is optimized, the returned light is reflected and away from the combiner, the glue heating problem of the pipe opening is solved, the returned light is prevented from hitting the combiner to cause heating, a waste light filtering device is additionally arranged on the output bare fiber, the device can selectively filter the cladding light, the light smaller than the NA of the outer cladding of the output optical fiber is continuously transmitted, the light greater than the NA of the outer cladding of the output optical fiber is filtered out in advance, the light cannot reach the coating layer, and the temperature of the output optical fiber coating layer is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0024] Figure 1 is a structural schematic view of an optical fiber combiner provided by the embodiments of the present application;

[0025] Figure 2 is a schematic view of a first view angle of a mirror and a bonding sleeve provided by the embodiments of the present application;

[0026] Figure 3is a schematic view of the second visual angle of the reflecting mirror and the adhesive sleeve provided by the embodiment of the utility model;

[0027] Figure 4 is a schematic view of the reflecting mirror section in the first case provided by the embodiment of the utility model;

[0028] Figure 5 is a schematic view of the reflecting mirror section in the second case provided by the embodiment of the utility model;

[0029] Figure 6 is a schematic view of the second glass sleeve provided by the embodiment of the utility model;

[0030] Figure 7 is a schematic view of the pump waste light filtering device section provided by the embodiment of the utility model;

[0031] Figure 8 is a schematic view of the structure before cutting the sleeve provided by the embodiment of the utility model;

[0032] Figure 9 is a schematic view of the structure after cutting the sleeve provided by the embodiment of the utility model. DETAILED DESCRIPTION

[0033] In the description of the utility model, the orientation or position relation indicated by the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "left", "right", "top", "bottom" and the like is the orientation or position relation based on the orientation or position relation shown in the drawings, and is only for the convenience of describing the utility model and does not require the utility model to be necessarily constructed and operated in a particular orientation, therefore should not be understood as a limitation on the utility model.

[0034] The utility model will be described in detail below in combination with specific embodiments. The following embodiments will help the person skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made. These all belong to the protection scope of the utility model.

[0035] It should be noted that, if there is no conflict, each feature in the embodiments of the utility model can be combined with each other, and all within the protection scope of the utility model. Unless otherwise defined, all technical and scientific terms used in the specification are the same as the meanings understood by the person skilled in the art belonging to the technical field of the utility model. The terms and orientation description used in the specification of the utility model are only for the purpose of describing the specific embodiment and are not used to limit the utility model.

[0036] Unless the context clearly requires otherwise, throughout the description and the claims, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. In description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure, and multiple implementations are contemplated. These terms in no way require that all embodiments or examples include the particular feature, structure, material, or characteristic. Furthermore, such terms can refer to a specific feature, structure, material, or characteristic, or to a combination of features, structures, materials, or characteristics. The embodiments are described herein with reference to particular examples, which are provided for illustration purposes only. The description is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Many variations and modifications are possible and will be readily apparent to those skilled in the art in light of this disclosure. Embodiments can include "specific" or "particular" features, structures, materials, or characteristics, but such terms are not intended to be limiting. Rather, such terms are used merely to identify a clearly defined embodiment or example. A particular feature, structure, material, or characteristic can be combined with one or more other particular features, structures, materials, or characteristics in any suitable manner.

[0037] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the following will be further described in detail with the help of the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model, and are not used to limit the utility model.

[0038] Embodiment 1

[0039] As Figure 1 and Figure 9 shown, the utility model discloses a kind of optical fiber combiner, including input optical fiber 1 and output bare fiber 2, one end of the input optical fiber 1 is provided with fused taper fiber bundle 3, and the input optical fiber 1 is connected with the output bare fiber 2 by the fused taper fiber bundle 3;First glass sleeve 4 is arranged on the input optical fiber 1, and the first glass sleeve 4 and the fused taper fiber bundle 3 form the shearing pipe gap 100, the shearing pipe gap 100 is provided with reflector 6 at the end away from the fused taper fiber bundle 3;Pump waste light filter device 7 for filtering out the pump waste light exceeding the outer cladding NA of the output bare fiber 2 is arranged on the output bare fiber 2.Through the reflector 6 in the above setting, the back light can be reflected and away from combiner, not only solve the problem of tube opening glue heating, but also avoid the situation that this part of light hits combiner again to cause heating;Through the pump waste light filter device 7 in the above setting, cladding light can be selectively filtered out, so that the light smaller than the outer cladding NA of output fiber continues to transmit, and the light larger than the outer cladding NA of output fiber is filtered out in advance, so that it cannot reach coating, thereby reducing the temperature of output fiber coating.

[0040] Reference Figure 1 , Figure 2 and Figure 3As shown, in some embodiments, the mirror 6 is arranged at one end of the shearing tube gap 100 away from the fused taper fiber bundle 3 by means of the adhesive sleeve 5; the adhesive sleeve 5 is sleeved and fixed on the first glass sleeve 4, and the mirror 6 is fixed on one end of the adhesive sleeve 5 towards the fused taper fiber bundle 3.

[0041] In some embodiments, the end face of the mirror 6 blocks one end of the shearing tube gap 100 away from the fused taper fiber bundle 3. In terms of position arrangement, the mirror 6 needs to block the first glass sleeve 4 to achieve the purpose of reflecting the returning light and moving away from the combiner.

[0042] In some embodiments, the inner diameter of the adhesive sleeve 5 is greater than the outer diameter of the first glass sleeve 4, the adhesive sleeve 5 is sleeved on the first glass sleeve 4 and fixed with the first glass sleeve 4 by means of dispensing. In some embodiments, the cross-sectional area of the mirror 6 is greater than the cross-sectional area of the adhesive sleeve 5, so that the mirror 6 can completely block the light towards the first glass sleeve 4 and the adhesive sleeve 5; the cross section of the mirror 6 is one of square, circular or any polygon.

[0043] Reference Figure 4 As shown, in some embodiments, the mirror 6 is arranged at one end of the shearing tube gap 100 away from the fused taper fiber bundle 3 by means of the adhesive sleeve 5; the adhesive sleeve 5 is sleeved and fixed on the first glass sleeve 4, and the mirror 6 is fixed on one end of the adhesive sleeve 5 towards the fused taper fiber bundle 3.

[0044] Reference Figure 5 As shown, in some embodiments, the mirror 6 is arranged at one end of the shearing tube gap 100 away from the fused taper fiber bundle 3 by means of the adhesive sleeve 5; the adhesive sleeve 5 is sleeved and fixed on the first glass sleeve 4, and the mirror 6 is fixed on one end of the adhesive sleeve 5 towards the fused taper fiber bundle 3.

[0045] Reference Figure 1 、 Figure 6 and Figure 7As shown, in some embodiments, the pump waste light filter device 7 comprises a second glass sleeve 701, a second through hole 702 is formed in the middle of the second glass sleeve 701, the diameter of the second through hole 702 is larger than the diameter of the output bare fiber 2, and the gap between the second through hole 702 and the output bare fiber 2 is filled with a medium 703 matching the refractive index of the outer cladding of the output bare fiber 2, and the refractive index of the second glass sleeve 701 is higher than the refractive index of the medium 703. In some embodiments, the outside of the second glass sleeve 701 is roughened to scatter the waste light and avoid heat accumulation on the glass sleeve.

[0046] In some embodiments, the output bare fiber 2 is provided with an output fiber coating layer 8 at one end away from the fused taper fiber bundle 3.

[0047] Through the above arrangement, the embodiments of the utility model provide an effective solution to the situation of glue heating of the mouth of the combiner and heating of the output fiber coating layer. The improvement of arranging the reflector 6 at the pipe cutting gap 100 directly avoids the return light from gathering on the glue, and without the need for a more complex laser etching process, the process operation becomes simpler and more reliable, and the cost is lower. The waste light filter device 7 on the output fiber has high requirements on the operation process, but can directly filter the pump waste light, so that the pump light passing through the waste light filter device 7 can be directly transmitted in the inner cladding of the output fiber, and will not leak to the coating layer, greatly reducing the heat accumulation on the coating layer.

[0048] The above is the description of the structure of the embodiments of the utility model, and the principle and manufacturing process of the utility model will be further described below.

[0049] After the fusion splicing of the fused taper fiber bundle 3 and the output bare fiber 2 is completed, referring to Figure 8 As shown, at this time, the first glass sleeve 4 on the combiner has not been subjected to pipe cutting operation, and the glass sleeve outside the fused taper fiber bundle 3 is an integrated glass sleeve with the first glass sleeve 4. Then the pipe cutting operation is performed on the combiner, and after the pipe cutting operation is completed, the pipe cutting gap 100 is as shown in Figure 9 As shown in Figure 9 On the basis, a bonding sleeve 5 with an inner diameter slightly larger than the first glass sleeve 4 is sleeved from the tail of the input fiber 1, and is fixed with the first glass sleeve 4 by glue dispensing, and then the round hole in the reflector 6 is slowly sleeved into the fiber bundle at the pipe cutting gap 100, and finally the reflector 6 and the bonding sleeve 5 are fixed, forming the device as shown in Figure 1 As shown, the finally obtained device. Although the shape of the pipe cutting gap 100 is uncontrollable, by adjusting the distance between the reflector 6 and the pipe cutting gap 100 at this end of the fused taper fiber bundle 3, the reflector 6 can reflect the light and move away from the combiner, and hit the packaging shell, avoiding the heating of the combiner itself.

[0050] On the basis of the above structure, a pump waste light filtering device 7 can be added at the output bare fiber 2 of the output fiber, and the pump waste light filtering device 7 is shown in the cross-sectional view Figure 7 As shown in the cross-sectional view, the second glass sleeve 701 is a high refractive index glass sleeve with an inner diameter slightly larger than the output bare fiber 2 of the output fiber, the second glass sleeve 701 is sleeved on the output bare fiber 2, and the gap inside is filled with a medium 703 with a refractive index matched with the outer cladding of the output fiber, while the output bare fiber 2 and the high refractive index second glass sleeve 701 are fixed, and finally the outside of the high refractive index second glass sleeve 701 is roughened to scatter the waste light and avoid heat accumulation on the second glass sleeve 701. In this way, the pump waste light exceeding the large NA of the output fiber received by the defects in the combiner and the fusion joint can be filtered out in advance by the pump waste light filtering device 7 on the output bare fiber 2, avoiding the heat accumulation and heating of the coating layer 8 of the output fiber. The pump waste light filtering device 7 can be set before the fusion of the fused taper fiber bundle 3 and the output bare fiber 2.

[0051] In summary, the high-power pump combiner must solve the problem of heat generation, so as to work as close to the theoretical design of high power value as possible and work stably for a long time; the utility model optimizes the pipe cutting scheme, places a mirror after cutting the pipe, can make the returned light reflect and move away from the combiner, not only solves the problem of heat generation of the pipe opening glue, but also avoids the part of light hitting the combiner again to cause heat generation; at the same time, an waste light filtering device is added on the output bare fiber, the device can selectively filter the cladding light, so that the light smaller than the NA of the outer cladding of the output fiber continues to transmit, and the light larger than the NA of the outer cladding of the output fiber is filtered out in advance, so that it cannot reach the coating layer, thereby reducing the temperature of the coating layer of the output fiber.

[0052] The above only describes the preferred embodiments of the utility model, and does not limit the utility model, any modification, equivalent replacement and improvement within the spirit and principle of the utility model should be included in the protection scope of the utility model. The contents not described in detail in the specification belong to the prior art known by the professional technical personnel.

Claims

1. A fiber combiner, characterized in that: The invention comprises an input optical fiber (1) and an output bare fiber (2), wherein a fused tapered optical fiber bundle (3) is provided at one end of the input optical fiber (1), and the input optical fiber (1) is connected to the output bare fiber (2) through the fused tapered optical fiber bundle (3); a first glass sleeve (4) is provided on the input optical fiber (1), and a shearing notch (100) is formed between the first glass sleeve (4) and the fused tapered optical fiber bundle (3), and a reflector (6) is provided at the end of the shearing notch (100) away from the fused tapered optical fiber bundle (3); and a pump waste light filtering device (7) for filtering out pump waste light exceeding the NA of the outer cladding of the output bare fiber (2) is provided on the output bare fiber (2).

2. The optical fiber combiner according to claim 1, wherein: The reflector (6) is arranged at one end of the shearing notch (100) away from the fused tapered optical fiber bundle (3) through a bonding sleeve (5); the bonding sleeve (5) is sleeved and bonded to the first glass sleeve (4), and the reflector (6) is bonded to one end of the bonding sleeve (5) facing the fused tapered optical fiber bundle (3).

3. The optical fiber combiner according to claim 2, wherein: The end face of the reflector (6) shields the tube cutting notch (100) away from one end of the fused tapered optical fiber bundle (3).

4. The optical fiber combiner according to claim 2, wherein: The inner diameter of the bonding sleeve (5) is greater than the outer diameter of the first glass sleeve (4); the bonding sleeve (5) is sleeved on the first glass sleeve (4) and fixed to the first glass sleeve (4) by glue dispensing.

5. The optical fiber combiner according to claim 2, wherein: The cross-sectional area of ​​the reflector (6) is greater than the cross-sectional area of ​​the bonding sleeve (5); and the cross-sectional area of ​​the reflector (6) is one of a circle and an arbitrary polygon.

6. The optical fiber combiner according to claim 1, wherein: A first through hole (601) is provided in the middle of the reflector (6), and the diameter of the first through hole (601) is consistent with the diameter of the input optical fiber (1).

7. The optical fiber combiner according to claim 6, characterized in that: The reflector (6) is provided with a snap-fit ​​opening (602), and the snap-fit ​​opening (602) is communicated with the through hole (601).

8. The optical fiber combiner according to claim 1, wherein: The pump waste light filtering device (7) comprises a second glass sleeve (701), a second through hole (702) is provided in the middle of the second glass sleeve (701), the diameter of the second through hole (702) is larger than the diameter of the output bare fiber (2), and the gap between the second through hole (702) and the output bare fiber (2) is filled with a medium (703) whose refractive index matches the outer cladding of the output bare fiber (2), and the refractive index of the second glass sleeve (701) is higher than the refractive index of the medium (703).

9. The optical fiber combiner according to claim 8, characterized in that: The outer side of the second glass sleeve (701) is roughened.

10. The optical fiber combiner according to any one of claims 1 to 9, characterized in that: The output bare fiber (2) is provided with an output optical fiber coating layer (8) at one end away from the fused tapered optical fiber bundle (3).

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