Semiconductor laser collimation system and fiber laser

Abstract

The invention provides a semiconductor laser collimation system and an optical fiber laser, and the collimation system comprises a collimation module which is used for fixing a lens and an optical fiber, a pumping chip which is used for transmitting pumping light, and a collimation lens group which is located at the light outlet side of the pumping chip and is used for collimating the pumping light; the pumping source optical fiber is located on the light emitting side of the collimating lens, and the pumping source optical fiber comprises an optical fiber grating formed through optical fiber inscribing; the pumping source, the collimating lens and the pumping source optical fiber are all arranged in the shell. According to the invention, the fiber bragg grating is formed by carrying out fiber inscribing on the pumping source fiber, and the fiber bragg grating is integrated in the collimation system, so that an external grating is not needed; the number of gratings is reduced, the cost is reduced, the number of welding points is reduced, and the problem of poor welding is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor lasers, and in particular to a semiconductor laser alignment system and a fiber laser. Background Art

[0002] Semiconductor lasers are increasingly used in communications, military, medical and other fields. As a semiconductor component, the market demand for semiconductor lasers is increasing. In recent years, high-power, high-beam-quality semiconductor lasers have been rapidly developed. The traditional method for preparing semiconductor lasers is to fuse the fiber grating after the pump source fiber and then fuse the active fiber, and the pump source fiber is generally different from the active fiber. This preparation method will produce more welding points, which is prone to poor welding problems.

[0003] Application Contents

[0004] The embodiments of the present application provide a semiconductor laser alignment system and a fiber laser, which form a fiber grating by fiber writing to reduce the number of fusion points and avoid the problem of poor fusion.

[0005] In one aspect, the present application provides a semiconductor laser alignment system, the semiconductor laser alignment system comprising:

[0006] case;

[0007] A pump chip, wherein the pump chip is used to emit pump light;

[0008] A collimation module, wherein the collimation module is used to fix a collimation lens and a pump source optical fiber;

[0009] A collimating lens, located at the light-emitting side of the pump chip, and used for collimating the pump light;

[0010] A pump source optical fiber, the pump source optical fiber is located at the light output side of the collimating lens, and the pump source optical fiber includes a fiber grating formed by optical fiber writing;

[0011] The pump chip, the collimating module, the collimating lens and the pump source optical fiber are all arranged in the housing.

[0012] In some possible embodiments, the semiconductor laser collimation system further includes an end cap, and the end cap is arranged between the collimating lens and the pump source optical fiber.

[0013] In some possible embodiments, the distance between the fiber grating and the end cap is 5 mm-10 mm.

[0014] In some possible embodiments, the bandwidth of the fiber Bragg grating is 38-40 mm.

[0015] In some possible embodiments, the fiber grating is a high-reflection grating.

[0016] In some possible embodiments, the pump source optical fiber is a passive optical fiber.

[0017] In a second aspect, an embodiment of the present application provides a fiber laser, which includes a semiconductor laser collimation system as described in any one of the above items, and further includes: a gain fiber, wherein the gain fiber is arranged on the light output side of the fiber grating.

[0018] In some possible embodiments, the gain fiber includes a primary gain fiber and a secondary gain fiber, and the semiconductor laser further includes a low-reflection grating, and the low-reflection grating is disposed between the primary gain fiber and the secondary gain fiber.

[0019] In some possible embodiments, the gain fiber and the pump source fiber are fibers of the same specification.

[0020] In some possible embodiments, the semiconductor laser further includes a mode stripper, and the mode stripper is located at the light output side of the secondary gain optical fiber.

[0021] The present application provides a semiconductor laser collimation system and a fiber laser, wherein the collimation system comprises: a collimation module for fixing a lens and an optical fiber, a pump chip for emitting pump light, a collimation lens group located on the light-emitting side of the pump chip, and used to collimate the pump light; a pump source optical fiber, the pump source optical fiber being located on the light-emitting side of the collimation lens, and the pump source optical fiber comprising a fiber grating formed by optical fiber writing; the pump source, the collimation lens, and the pump source optical fiber are all arranged in a housing. The present application forms a fiber grating by performing optical fiber writing on the pump source optical fiber, and integrates the fiber grating into the collimation system, without the need for an external grating; while reducing the number of gratings and reducing costs, it also reduces the number of fusion points and reduces the problem of poor fusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of an embodiment of a semiconductor laser alignment system provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of an embodiment of a semiconductor laser provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0026] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0027] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0029] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0030] For details, please refer to Figure 1 A schematic diagram of an embodiment of a semiconductor laser alignment system provided in an embodiment of the present application. Figure 1 As shown, the semiconductor laser alignment system 10 comprises:

[0031] A pump chip 101, the pump chip 101 is used to emit pump light;

[0032] The collimating lens 102 is located at the light-emitting side of the pump chip 101 , and the pump chip 101 is used to collimate the pump light.

[0033] The pump source optical fiber 103 is located at the light output side of the collimating lens 102 . The pump source optical fiber 103 includes a fiber grating 104 formed by optical fiber writing.

[0034] It should be noted that in an actual semiconductor laser alignment system, the semiconductor laser alignment system also includes an external shell and a alignment module for fixing a collimating lens and a pump source optical fiber. The collimating module, the pump chip 101, the collimating lens 102, the pump source optical fiber 103 and other structures are all integrated in the shell to form a semiconductor laser alignment system.

[0035] The present application provides a semiconductor laser collimation system and a fiber laser, wherein the collimation system comprises: a collimation module for fixing a lens and an optical fiber, a pump chip for emitting pump light, a collimation lens group located on the light-emitting side of the pump chip, and used to collimate the pump light; a pump source optical fiber, the pump source optical fiber being located on the light-emitting side of the collimation lens, and the pump source optical fiber comprising a fiber grating formed by optical fiber writing; the pump source, the collimation lens, and the pump source optical fiber are all arranged in a housing. The present application forms a fiber grating by performing optical fiber writing on the pump source optical fiber, and integrates the fiber grating into the collimation system, without the need for an external grating; while reducing the number of gratings and reducing costs, it also reduces the number of fusion points and reduces the problem of poor fusion.

[0036] The pump chip 101 provided in the present application is used to emit pump light. In a specific embodiment, the pump chip can emit corresponding infrared light for the infrared laser. The semiconductor laser collimation system provided in the present application also includes a collimation module, which is used to fix the collimation lens and the pump source optical fiber; the collimation function is actually performed mainly by the collimation lens. The pump chip 101 can generally include a fast collimation lens and a slow collimation lens, that is, the pump light usually needs to be collimated twice, namely fast collimation and slow collimation; the specific collimation process can refer to the prior art, which will not be described here. The collimated pump light will be injected into the pump source optical fiber 103, and will be emitted from the semiconductor laser via the pump light optical fiber and the subsequently connected grating and other structures.

[0037] Please refer to Figure 1 ,exist Figure 1 In the embodiment shown, the semiconductor laser collimation system further includes an end cap 105; wherein the end cap 105 is a high-power device designed and processed for the output end face of a high-power fiber laser, which can effectively reduce the beam distortion of the pump light. The end cap 105 in the present application is located between the collimating lens 102 and the pump source fiber 103; Figure 1 Taking the structure shown as an example, the end cap 105 is located on the light-emitting side of the collimating lens, and the collimated pump light is directly injected into the end cap 105; and the other end of the end cap is fused with the pump source fiber, and the pump light is injected into the pump source fiber through the end cap 105. A fiber grating 104 is also formed on the pump source fiber 103 at a position away from the end cap 105. The fiber grating 104 is formed by fiber writing on the pump source fiber 103, rather than fusing the grating on the side of the pump source fiber away from the end cap as shown in conventional technology. There is no fusion point between the fiber grating 104 prepared in this way and the pump source fiber 103, which effectively saves the number of fusion points and the fusion time to solve the problem of poor fusion.

[0038] In some embodiments, when actually preparing a semiconductor collimation system, a pump source fiber is first obtained, and then the pump source fiber is fiber-written to obtain a pump source fiber including a fiber Bragg grating 104; then the pump source fiber including the fiber Bragg grating 104 and the pump chip, collimation lens and other structures are integrated in a housing, thereby forming a semiconductor laser collimation system including the fiber Bragg grating 104. That is, the semiconductor laser collimation system provided by the present application needs to integrate the fiber Bragg grating 104 formed on the pump source fiber by fiber writing into the collimation system, and there is no need to fuse the fiber Bragg grating 104 outside the collimation system, and the collimation system itself can meet the application requirements of pumping and fiber Bragg grating 104.

[0039] In a specific embodiment, the process of optical fiber writing of the pump source may include:

[0040] Determine the optical fiber of the fiber Bragg grating 104 to be written, that is, determine the pump source optical fiber, and place the pump source optical fiber horizontally along the x direction; then it is necessary to determine the refractive index range of the fiber Bragg grating 104 to be written, as well as the corresponding shape and size of the fiber Bragg grating 104; then determine the average laser power and laser beam diameter during writing based on some parameters of the aforementioned fiber Bragg grating. When actually writing, it is necessary to determine the writing position of the fiber Bragg grating 104 in the pump source optical fiber, that is, determine which section of the pump source optical fiber needs to be written. Then, the laser determined by the average power and beam diameter is incident and focused on the writing position, and the laser is controlled to move uniformly the set distance to achieve writing of the pump source optical fiber, and obtain the fiber Bragg grating 104. The aforementioned writing process briefly describes how to write the pump source optical fiber to obtain the fiber Bragg grating 104. The specific writing process can refer to the prior art and is not limited here.

[0041] In an embodiment of the present application, the fiber Bragg grating 104 can be a Bragg grating obtained by fiber writing. Due to the characteristics of the Bragg grating, when the grating is written, the sensitivity of the grating to temperature and stress is determined. In the actual use scenario of the semiconductor laser, the temperature around the grating and the stress it bears may also change, which causes the characteristics of the Bragg grating to change accordingly, causing the central wavelength of the pump light that penetrates the Bragg grating to shift. Therefore, the present application also adds an additional pump light detection module for detecting the light emitted by the fiber Bragg grating 104; when the offset of this part of the light exceeds the set threshold, it can be determined that the light grating at this time may be abnormal and needs to be promptly alarmed. Therefore, the pump light detection module in the present application is usually arranged on the light-emitting side of the fiber Bragg grating 104, and the pump light detection module can be arranged inside the semiconductor laser collimation system, or it can be arranged outside the semiconductor laser collimation system.

[0042] It should be noted that in the embodiment of the present application, the pump source fiber is usually a passive fiber; writing on the pump source fiber is also writing on the passive fiber. Compared with writing on the active fiber, since the passive fiber is not doped with other impurities, the actual writing difficulty is lower, the process requirements are not high, and it is easy to implement. When the collimation system is actually prepared, the distance between the fiber grating 104 and the end cap is 5 mm-10 mm, such as 5 mm, and the bandwidth of the fiber grating 104 is 38-40 mm, such as 40 mm.

[0043] like Figure 2 FIG. 1 is a schematic diagram of the structure of an embodiment of a fiber laser provided in an embodiment of the present application. Figure 2In the embodiment shown, the fiber laser includes a pump source, and the pump source includes the aforementioned semiconductor laser collimation system 10, and also includes a gain fiber 20; and the gain fiber 20 is arranged on the light-emitting side of the fiber grating 104, that is, the gain fiber is located on the light-emitting side of the entire semiconductor laser collimation system 10. Figure 2 In the embodiment, the gain fiber 20 may include a primary gain fiber 201 and a secondary gain fiber 202, and the primary gain fiber 201 and the secondary gain fiber 202 are sequentially arranged on the light-emitting side of the entire semiconductor laser collimation system 10. The semiconductor laser also includes a low-reflection grating 30, and the low-reflection grating 30 is located between the primary gain fiber 201 and the secondary gain fiber 202. The low-reflection grating 30 and the fiber grating 104 in the collimation system together constitute the resonant cavity in the semiconductor laser. Among them, the fiber grating 104 is a high-reflection grating, and the reflectivity of the high-reflection grating pump light is usually greater than 90%; and the reflectivity of the low-reflection grating 30 to the signal is less than 12%, and the two constitute the resonant cavity of the laser. In some embodiments, the low-reflection grating 30 can be fused between the primary gain fiber 201 and the secondary gain fiber 202; in other embodiments, the low-reflection grating 30 can also be a grating obtained by fiber writing, so that there is no fusion point between the low-reflection grating 30 and the primary gain fiber 201 and the secondary gain fiber 202, thereby further reducing the fusion point and reducing the probability of poor fusion. However, since the gain fiber is an active fiber, it is difficult to write on the active fiber. Therefore, it is usually sufficient to form a fiber grating, that is, a high-reflection grating, by writing on the passive fiber. Whether to form a low-reflection grating by writing can be determined according to actual needs. In other embodiments, the gain fiber 20 in the present application can also include only the primary gain fiber, and not include the primary gain fiber and the secondary gain fiber at the same time; it can be set specifically according to actual needs and is not limited here.

[0044] In the embodiment of the present application, the gain fiber 20 is an active fiber, that is, the primary gain fiber 201 and the secondary gain fiber 202 are both active fibers. Specifically, the gain fiber 20 can be a double-clad or triple-clad fiber with a core doped with rare earth elements, and the doped rare earth elements are one or more elements of ytterbium, erbium, holmium, thulium, samarium, bismuth, etc., so as to achieve the output of different laser wavelengths. In a specific embodiment, the gain fiber can be a double-clad ytterbium-doped fiber. The gain fiber 20 and the pump source fiber 103 in the present application can be optical fibers of the same specification; the optical fibers of the same specification mentioned here mainly refer to the core and the cladding; that is, the two can have a core of the same geometric size and a cladding of the same geometric size. The fiber laser provided in the present application is highly integrated and has a large power, so there is no need to set a fiber combiner in the fiber laser, and there is no need to use a fiber combiner to couple multiple pump lights and then transmit the pump light to the resonant cavity. Using a high-power pump chip to replace multiple low-power pump chips reduces the number of pump chips and thus reduces the number of welding points of the pump chips. While increasing the power of the fiber laser, it can also simplify the laser structure design, reduce the welding time, and reduce welding defects. At the same time, since the beam combiner is omitted, the divergence problem of the beam combiner for the pump light is eliminated, thereby effectively controlling the divergence angle of the pump light output by the pump source and improving the conversion efficiency of the gain fiber 20; thereby, the output laser power is increased while the input power remains unchanged, that is, the overall power of the semiconductor laser is increased, and the preparation of a high-power laser is realized.

[0045] In other embodiments, the gain fiber 20 still includes a primary gain fiber 201 and a secondary gain fiber 202, but unlike the aforementioned embodiments, the primary gain fiber 201 is a passive fiber, and the secondary gain fiber 202 is an active fiber; at the same time, the low-reflection grating 30 arranged on the light-emitting side of the primary gain fiber 201 adopts a passive fiber that matches the primary gain fiber, and the low-reflection grating can also be obtained by writing the primary gain fiber 201. At this time, the semiconductor laser collimation system may include multiple pump chips such as a main pump chip and an auxiliary pump chip, which emit main pump light and auxiliary pump light respectively; and the semiconductor laser collimation system also includes a beam combiner, and the main pump light and the auxiliary pump light need to be combined by the beam combiner and then enter the collimation lens for collimation; the combined and collimated light beams are also injected into the pump source fiber, and are emitted through the fiber grating 104 on the pump source fiber 103.

[0046] In the above embodiment, the fiber Bragg grating 104, the primary gain fiber 201 and the low-reflection grating 30 together constitute a fiber oscillator assembly; at this time, the combined light obtained after the main pump light and the auxiliary pump light are combined will be injected into the fiber oscillator assembly. The combined light is converted into a transitional pump light with a wavelength between the wavelength of the main pump light and the wavelength of the auxiliary pump light by the fiber oscillator assembly, and then injected into the secondary gain fiber 202. And the gain fiber mainly plays a role in transmitting the main pump light, while the secondary gain fiber 202 will amplify the main pump light, and the auxiliary pump light will provide energy for the amplification of the main pump light, so that the semiconductor laser outputs a high-power main pump light, ensuring the quality and power of the laser output. Although the embodiment includes multiple pump chips and a beam combiner, in this application, it is usually only necessary to set one main pump chip and one auxiliary pump chip. Compared with more than two pump sources in the prior art, the number of pump sources can still be reduced, thereby reducing the number of fusion points between the pump chip and the beam combiner. In this embodiment, the fiber Bragg grating 104 is still connected to the pump source fiber by the fiber writing method, and there is no fusion point between the two, which also reduces the number of fusion points. Therefore, this embodiment can reduce the number of fusion points and reduce poor fusion under the premise of achieving high-power laser output.

[0047] In the above embodiment, the primary gain fiber 201 and the secondary gain fiber 202 are both multi-clad fibers, and the main pump light and the auxiliary pump light can achieve gain and transmission through different fiber cross-sectional areas of the two gain fibers, respectively. The processes are relatively independent, and heat is dissipated separately to reduce the influence of thermal effects during laser amplification. The semiconductor laser provided in the present application can also be additionally provided with a temperature control device and a heat dissipation device, wherein the temperature control device is mainly used to detect the temperature change at the gain fiber 20 (including the low-reflection grating 30), and the specific structure and position of the temperature control device can be changed according to actual needs, which is not limited here. The heat dissipation device can dissipate heat from the gain fiber 20. In some embodiments, a heat dissipation medium can be coated on the surface of the gain fiber 20 to dissipate heat from the gain fiber 20 and improve the beam quality. In a specific embodiment, a heat dissipation glue can be coated on the surface of the gain fiber 20 to dissipate heat.

[0048] In the aforementioned embodiment, the fiber Bragg grating 104 and the low-reflection grating 30 form a resonant cavity; in other embodiments, the low-reflection grating can be multiple, and multiple low-reflection gratings form a multi-core low-reflection grating array. The multi-core low-reflection grating array can form multiple resonant cavities with the fiber Bragg grating to select wavelengths, and after multiple oscillations, different lasers can be stably output. In other embodiments, both the fiber Bragg grating and the low-reflection grating can be multiple, and multiple fiber Bragg gratings and multiple low-reflection gratings can be cross-arranged, and a resonant cavity can be formed between any adjacent fiber Bragg gratings and low-reflection gratings, and the function of wavelength selection and output of different lasers can also be realized. In a specific embodiment, the semiconductor laser can include two fiber Bragg gratings and two low-reflection fibers, and they are arranged in the order of fiber Bragg grating-1 low-reflection grating 1-fiber Bragg grating 2-low-reflection grating 2, and a gain fiber is also arranged between two adjacent gratings. At this time, the fiber Bragg grating 1 and the low-reflection grating 1 form a resonant cavity, and the low-reflection grating 1 and the fiber Bragg grating 2 also form a resonant cavity. That is, in this embodiment, different resonant cavities may share gratings, which can reduce the number of gratings, reduce costs and welding points.

[0049] It should be noted that, in the above-mentioned embodiment, a high-reflection grating closest to the semiconductor laser collimation system is formed by optical fiber writing and integrated in the semiconductor laser collimation system. In this way, the number of fusion points can be reduced compared to the prior art, and poor fusion can be reduced. If there are multiple fiber gratings, in addition to the fiber grating integrated in the collimation system, whether other fiber gratings are obtained by optical fiber writing, and whether the active fiber is written or the passive fiber is written, can be adjusted according to actual needs. Similarly, for low-reflection gratings and gain fibers, the gain fiber can include active fibers or passive fibers, and the position of the low-reflection grating in the fiber laser, and whether the low-reflection grating is obtained by writing, and whether the low-reflection grating is obtained by writing the active fiber or the passive fiber in the gain fiber, can be adjusted according to actual needs. This application is not limited, and other schemes do not represent limitations on this application.

[0050] Figure 2 In the illustrated embodiment, the semiconductor laser further includes a mode stripper 40 and an optical fiber output head 50. The mode stripper 40 is a forward mode stripper, which is used to filter out cladding pump light and high-order mode lasers. The optical fiber output head 50 is used as an optical fiber output device for outputting the expanded beam output of the signal laser. The optical fiber output head 50 can effectively reduce the energy density of the output laser and improve the overall reliability of the laser. In other embodiments, the output side of the mode stripper 40 can also be connected to a fiber isolator, which is arranged between the mode stripper and the optical fiber output head. The fiber isolator is mainly used to isolate the return light and determine the unidirectional propagation of the output laser.

[0051] In some embodiments, the operating wavelength of the semiconductor laser is typically one of 915 nm, 940 nm or 976 nm, or a combination of multiple wavelengths. Of course, depending on actual needs, the wavelength of the semiconductor laser can also be other wavelengths. The selection is relatively flexible and is not limited here.

[0052] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0053] The semiconductor laser alignment system and the semiconductor laser provided in the embodiments of the present application are introduced in detail above. The principles and implementation methods of the present application are explained in this article using specific examples. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A semiconductor laser alignment system, characterized in that: include: case; A pump chip, wherein the pump chip is used to emit pump light; A collimation module, wherein the collimation module is used to fix a collimation lens and a pump source optical fiber; A collimating lens, located at the light-emitting side of the pump chip, and used for collimating the pump light; A pump source optical fiber, the pump source optical fiber is located at the light output side of the collimating lens, and the pump source optical fiber includes a fiber grating formed by optical fiber writing; The pump chip, the collimating module, the collimating lens and the pump source optical fiber are all arranged in the housing.

2. The semiconductor laser alignment system according to claim 1, characterized in that: The semiconductor laser collimation system further comprises an end cap, which is arranged between the collimating lens and the pump source optical fiber, and the end cap is fused with the pump source optical fiber.

3. The semiconductor laser alignment system according to claim 2, characterized in that: The distance between the fiber grating and the end cap is 5 mm to 10 mm.

4. The semiconductor laser alignment system according to claim 1, characterized in that: The bandwidth of the fiber grating is 38-40 mm.

5. The semiconductor laser alignment system according to claim 1, characterized in that: The fiber grating is a high-reflection grating.

6. The semiconductor laser alignment system according to claim 1, characterized in that: The pump source optical fiber is a passive optical fiber.

7. A fiber laser, characterized in that: The fiber laser comprises the semiconductor laser collimation system according to any one of claims 1 to 6, and further comprises: a gain fiber, wherein the gain fiber is arranged on the light output side of the fiber grating.

8. The fiber laser according to claim 7, characterized in that: The gain fiber includes a primary gain fiber and a secondary gain fiber, and the semiconductor laser further includes a low-reflection grating, which is arranged between the primary gain fiber and the secondary gain fiber.

9. The optical fiber laser according to claim 7, characterized in that: The gain optical fiber and the pump source optical fiber are optical fibers of the same specification.

10. The optical fiber laser according to claim 7, characterized in that: The semiconductor laser further comprises a mode stripper, and the mode stripper is located at the light output side of the secondary gain optical fiber.

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