Fiber laser and laser processing equipment

Abstract

The utility model discloses an optical fiber laser and laser processing equipment, which are provided with a laser module for outputting laser beams, a guide light module for outputting guide light beams, a wavelength division multiplexer for connecting the laser module and the guide light module, and a reflection module positioned between the guide light module and the wavelength division multiplexer, the wavelength division multiplexer is used for converging the laser beam and the guiding light beam and guiding the laser beam to machine the workpiece to be machined through the guiding light beam, and the reflection module is at least used for reflecting a return light beam formed when the laser beam machines the workpiece to be machined. And furthermore, the reflection module arranged in the application can reflect the return light, so that the damage of the return light to the guide light module is reduced.

Description

Technical Field

[0001] This utility model relates to the field of laser technology, and in particular to a fiber laser and laser processing equipment. Background Technology

[0002] In related technologies, red light emitted from a red light source is used as an indicator light in fiber lasers. Before marking high-reflectivity materials, an indicator light emits an indicator light to confirm the starting position of the marking, replacing the laser. During marking, the indicator light turns off, and the laser is output to engrave the material. However, a problem exists: high-reflectivity materials generate reflected light during engraving, which enters the laser's interior along the laser output port and damages the internal red light source. Consequently, the indicator light becomes damaged or ineffective, or its power is weakened, rendering it useless as an indicator light. Utility Model Content

[0003] This invention provides a fiber laser and laser processing equipment to reduce the impact of reflected light on the indicator laser in related technologies.

[0004] According to one aspect of the present invention, a fiber laser is provided, comprising:

[0005] Laser module, used to output laser beam;

[0006] The guide light module is used to output a guide light beam;

[0007] A wavelength division multiplexer is used to connect the laser module and the guide light module, and to combine the laser beam and the guide light beam;

[0008] A reflection module is disposed between the guide light module and the wavelength division multiplexer, and the reflection module is used at least to reflect the return light beam formed when the laser beam processes the workpiece.

[0009] Optionally, the reflection module is a processing light reflection module, the period of which is determined by the wavelength of the return light beam and the effective refractive index of the processing light reflection module. The processing light reflection module is also used to ensure that the difference between the output power of the guide light module and the working power of the guide light beam is within a preset range. The processing light reflection module is a fiber Bragg grating.

[0010] Optionally, the laser module includes a resonant cavity and an amplification stage;

[0011] The wavelength division multiplexer is located inside the resonant cavity, or between the resonant cavity and the amplification stage.

[0012] Optionally, when the output power of the resonant cavity is greater than or equal to the damage threshold of the wavelength division multiplexer, and the power inside the resonant cavity is less than the damage threshold of the wavelength division multiplexer, the wavelength division multiplexer is located inside the resonant cavity;

[0013] When the output power of the resonant cavity is less than the damage threshold of the wavelength division multiplexer, and the power inside the resonant cavity is greater than the damage threshold of the wavelength division multiplexer, the wavelength division multiplexer is located between the resonant cavity and the amplification stage.

[0014] Optionally, the laser module further includes a first pump unit, a first gain fiber, and a resonant cavity, wherein the resonant cavity includes a first fiber Bragg grating and a second fiber Bragg grating for relative reflection, wherein...

[0015] The output of the first pump unit is connected to the resonant cavity via an optical fiber combiner, and the first gain fiber is disposed inside the resonant cavity;

[0016] When the wavelength division multiplexer is located inside the resonant cavity, the first end of the wavelength division multiplexer is connected to the first fiber Bragg grating, the second end is connected to the first gain fiber, and the third end is connected to the return beam input end of the reflection module.

[0017] When the wavelength division multiplexer is located between the resonant cavity and the amplification stage of the laser module, the first end of the wavelength division multiplexer is connected to the output end of the resonant cavity, the second end is connected to the amplification stage, and the third end is connected to the return beam input end of the reflection module.

[0018] Optionally, the resonant cavity further includes a Q-switch located between the first fiber Bragg grating and the first gain fiber.

[0019] Optionally, the amplification stage of the laser module includes a second pump unit, a second fiber combiner, and a second gain fiber;

[0020] One side of the second fiber combiner is used to connect the second pump unit and the resonant cavity output end of the laser module, and the other side is used to connect the second gain fiber. The other end of the second gain fiber is used to output the laser beam and the guide beam.

[0021] Optionally, the reflection module further includes a pump light reflection module, which is disposed between the processing light reflection module and the guide light module, or between the processing light reflection module and the wavelength division multiplexer, wherein the pump light reflection module is a fiber Bragg grating.

[0022] Optionally, the guide light module is one of a red light source, a green light source, a violet light source, or a blue light source.

[0023] According to another aspect of the present invention, an embodiment of the present invention also provides a laser processing device, including a fiber laser as described in any embodiment of the present invention.

[0024] The technical solution of this utility model embodiment involves setting a reflection module in the transmission path of the guide light module. The reflection module is used to reflect the reflected light beam generated when the laser beam processes the workpiece. Furthermore, the reflection module provided in this application can reflect the reflected light, preventing the reflected light generated by the high reflectivity material during engraving from entering the laser's interior along the laser output port and damaging the internal red light source. In other words, the reflection module can reduce the impact of the reflected light on the guide light module, thereby improving the performance of the guide light module.

[0025] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a block diagram of the fiber laser provided in the embodiments of this utility model;

[0028] Figure 2 This is a block diagram of a fiber laser provided in one embodiment of the present invention;

[0029] Figure 3 This is a block diagram of a fiber laser provided in another embodiment of the present invention;

[0030] Figure 4 This is a block diagram of a fiber laser provided in another embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the optical path of the fiber laser provided in this embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the optical path of a fiber laser provided in one embodiment of the present invention;

[0033] Figure 7This is a schematic diagram of the optical path of a fiber laser provided in another embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the optical path of a fiber laser provided in another embodiment of this utility model;

[0035] Figure 9 This is a schematic diagram of the optical path of a fiber laser provided in another embodiment of the present invention.

[0036] Reference numerals: 100, Fiber laser; 101, Laser module; 102, Guide light module; 103, Wavelength division multiplexer; 104, Reflection module; 105, Workpiece to be processed; 1011, Resonant cavity; 1012, Amplification stage; 106, First pump unit; 107, First fiber combiner; 108, First gain fiber; 109, First fiber Bragg grating; 110, Second fiber Bragg grating; 111, Second pump unit; 112, Third pump unit; 113, Second fiber combiner; 114, Second gain fiber; 115, Pump light reflection module; 116, Q-switch; 1041, Processing light reflection module. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] Figure 1 This is a block diagram of the fiber laser provided in the embodiments of this utility model. Figure 2This is a block diagram of the fiber laser provided in the embodiments of this utility model; as shown... Figure 1 and Figure 2 As shown, the fiber laser 100 includes:

[0040] Laser module 101 is used to output a laser beam;

[0041] The guide light module 102 is used to output a guide light beam;

[0042] Wavelength division multiplexer 103 is used to connect laser module 101 and guide light module 102, and to combine laser beam and guide light beam so as to guide laser beam to process workpiece 105 through guide light beam;

[0043] The reflection module 104 is connected to the guide light module 102 and the wavelength division multiplexer 103 respectively. The reflection module 104 is used to reflect at least the return light beam formed when the laser beam is processed on the workpiece 105.

[0044] It is understood that the laser module 101 can be a continuous laser or a pulsed laser. The selection is mainly based on the processing method of the workpiece 105. For example, continuous lasers are mainly used for metal cutting, welding, or drilling, while pulsed lasers are mainly used for laser marking.

[0045] The guide light module 102 can be a visible light laser, for example, it can be a red light source, a green light source, a violet light source or a blue light source. In order to better guide the laser output by the laser module 101, a red light source is usually used in actual working conditions.

[0046] Wavelength division multiplexer 103 is located inside laser module 101 (e.g. Figure 1 (as shown) or outside the laser module 101 (such as...) Figure 2 As shown, it can connect the laser module 101 and the guide light module 102, and can merge the guide light beam into the laser beam, thereby acting on the workpiece 103 at the same time.

[0047] The working principle of the aforementioned fiber laser 100 is as follows: the wavelength division multiplexer 103 merges the guide beam into the laser beam, so that the guide beam is mixed with the laser beam output from the laser module 101. Furthermore, during the processing of the workpiece 105, the guide beam and the laser beam act together on the workpiece 105, and the spot position of the laser beam output from the laser module 101 can be adjusted according to the position of the guide beam and the processing requirements of the workpiece 105. During processing, the workpiece 105 generates a return beam from the laser beam. This return beam passes through the optical fiber and the wavelength division multiplexer 103 in the laser module 101 and returns to the guide beam module 102. In this application, a reflection module 104 reflects the return beam to prevent it from touching the guide beam module 102 and causing damage such as overheating. Therefore, the reflection module provided in this application can reflect the reflected light to prevent the reflected light generated by the high reflectivity material during engraving from entering the laser's interior along the laser output port and damaging the internal red light source. In other words, the reflection module can reduce the impact of the reflected light on the guide light module to improve the performance of the guide light module.

[0048] Optionally, the reflection module 104 includes a processed light reflection module 1041, which is a fiber Bragg grating for reflecting the returned light. The period of the fiber Bragg grating is determined by the wavelength of the returned light beam and the effective refractive index of the fiber Bragg grating. The processed light reflection module 1041 is also used to ensure that the difference between the output power of the guide light module and the working power of the guide light beam is within a preset range.

[0049] In other words, the reflection module 104 is configured as a Bragg grating. The fiber core of this Bragg grating has a periodic or aperiodic perturbation of the effective refractive index. Under this periodic / aperiodic perturbation, when the Bragg condition is satisfied, light (propagating along the fiber) is reflected within a narrow wavelength range. The Bragg condition formula is λ = 2nΛ, where λ is the wavelength of the reflected light in vacuum, Λ is the grating period, and n is the effective refractive index of the fiber. Therefore, according to this Bragg formula, light of other wavelengths does not satisfy the Bragg condition and is almost unaffected by the Bragg grating. Thus, this Bragg grating is used to reflect the light processed in the application and does not affect the output wavelength of the indicator red light; in other words, it does not affect the power of the red light source. It should be noted that the processing light reflection module 1041 is a 99.5% reflectivity main wavelength grating (i.e., the wavelength of the returned light of the final laser beam output by the laser module 101, typically 1064nm).

[0050] Therefore, during the reflection of the return light beam, the reflection module 104 can ensure that the output power of the guide light module 102 is almost unaffected. In other words, the return light attenuator 104 can ensure that the difference between the output power of the guide light module 102 and the operating power of the guide light beam is within a preset range.

[0051] In other words, the reflection module 104 attenuates the reflected light beam independently without attenuating the power of the guide light beam, thus not affecting the normal function of the guide light module 102. Consequently, the guide light module 102 will not experience damage or failure of the indicator light, or its power will be too weak to function as an indicator light. Therefore, while the reflection module 104 attenuates the reflected light beam, preventing damage to the guide light module 102, it also allows the guide light beam to pass completely without attenuation, ensuring the output power of the guide light module 102 and extending the lifespan of the fiber laser.

[0052] In another embodiment, the reflected light can be further attenuated by wrapping it around the pigtail of the guide light module 102 between the guide light module 102 and the reflection module 104.

[0053] Figure 3 This is a block diagram of a fiber laser provided in another embodiment of the present invention; Figure 4 This is a block diagram of a fiber laser provided in another embodiment of the present invention. Optionally, as shown... Figure 3 and Figure 4 As shown, the laser module 101 includes a resonant cavity 1011 and an amplification stage 1012;

[0054] The wavelength division multiplexer 103 is located inside the resonant cavity 1011, or between the resonant cavity 1011 and the amplification stage 1012.

[0055] Understandably, the laser module 101 mainly consists of a resonant cavity 1011 and an amplification stage 1012. In order to use the light output from the guide light module 102 as the guide light in the laser system, a wavelength division multiplexer 103 (WDM) needs to be added to the laser module 101. The function of the WDM is to multiplex optical signals of different wavelengths onto the same optical fiber for transmission, thereby achieving the coexistence of the guide light and the main laser wavelength.

[0056] The design and placement of the WDM (Wave Mirror) need to be determined based on its energy handling capacity. This is because the WDM may be affected by high-energy optical signals during operation, and insufficient energy handling capacity may lead to device damage or performance degradation. Therefore, during system design, the placement of the WDM must be rationally selected based on the output power of the laser module 101, the power of the guide light module 102, and the rated energy handling capacity of the WDM to ensure stable system operation and efficient transmission.

[0057] For example, when the output power of the resonant cavity 1011 is greater than or equal to the damage threshold of the wavelength division multiplexer 103, and the power inside the resonant cavity 1011 is less than the damage threshold of the wavelength division multiplexer 103, the wavelength division multiplexer 103 is located inside the resonant cavity 1011; when the output power of the resonant cavity 1011 is less than the damage threshold of the wavelength division multiplexer 103, and the power inside the resonant cavity 1011 is greater than the damage threshold of the wavelength division multiplexer 103, the wavelength division multiplexer 103 is located between the resonant cavity 1011 and the amplification stage 1012. That is, when the output power of the resonant cavity 1011 is less than the damage threshold of the wavelength division multiplexer 103, and the power inside the resonant cavity 1011 is greater than the damage threshold of the wavelength division multiplexer 103, in order to ensure the normal function of the wavelength division multiplexer 103 and avoid significant damage to the wavelength division multiplexer 103 caused by the energy of the resonant cavity 1011, the wavelength division multiplexer 103 is positioned between the resonant cavity 1011 and the amplification stage 1012. Conversely, wavelength division multiplexer 103 can be set inside resonant cavity 1011. If all are within the damage threshold, the optical performance can be balanced for selection.

[0058] When the wavelength division multiplexer 103 is located inside the resonant cavity 1011, the wavelength division multiplexer 103 can avoid the high temperature of the main oscillator laser emitted from the resonant cavity 1011. When the wavelength division multiplexer 103 is located between the resonant cavity 1011 and the amplification stage 1012, the wavelength division multiplexer 103 will not affect the length of the resonant cavity 1011.

[0059] Figure 5 This is a schematic diagram of the optical path of a fiber laser provided in an embodiment of this utility model. Optionally, as... Figure 5 As shown, the laser module 10 includes a first pump unit 106, a first gain fiber 108 and a resonant cavity 1011 arranged sequentially along the first pump light transmission direction. The resonant cavity 1011 includes a first fiber Bragg grating 109 that forms relative reflection.

[0060] The output end of the first pump unit 106 is connected to the resonant cavity 1011 through the first fiber combiner 107, and the first gain fiber 108 is disposed in the resonant cavity 1011.

[0061] When the wavelength division multiplexer 103 is located inside the resonant cavity 1011, the first end of the wavelength division multiplexer 103 is connected to the first fiber Bragg grating 109, the second end is connected to the first gain fiber 108, and the third end is connected to the return beam input end of the reflection module 104.

[0062] When the wavelength division multiplexer 103 is located between the resonant cavity 1011 and the amplification stage 1012 of the laser module 101, the first end of the wavelength division multiplexer 103 is connected to the output end of the resonant cavity 1011, the second end is connected to the amplification stage 1012, and the third end is connected to the return beam input end of the reflection module 104.

[0063] The first fiber Bragg grating 109 and the second fiber Bragg grating 110 form a pair of reflectors, enabling the first pump beam from the first pump unit 106 to reflect back and forth between them, forming a resonant cavity. The first fiber Bragg grating 109 is a high-reflectivity grating with a reflectivity greater than 99% (preferably greater than 99.5%), and the second fiber Bragg grating 110 is a low-reflectivity grating with a reflectivity of 10%-50% (preferably 10%).

[0064] Understandably, the first pump unit 106 outputs the first pump beam, which enters the gain fiber 108 through the first fiber combiner 107, then passes through the wavelength division multiplexer 103 to reach the first fiber Bragg grating 109, and after being reflected by the first fiber Bragg grating 109, it reaches the second fiber Bragg grating 110 along the reverse path. Part of the first pump beam is output to the amplification stage 1012 by the second fiber Bragg grating 110 after being amplified by the resonant cavity gain, and part of the first pump beam is reflected back to the resonant cavity 1011 by the second fiber Bragg grating 110 along the original pump path.

[0065] Figure 6 This is a schematic diagram of the optical path of the fiber laser provided in this embodiment of the present invention. Since the first pump beam, when resonating within the resonant cavity 1011, passes through the wavelength division multiplexer 103, if the pump beam is not sufficiently absorbed by the first gain fiber 108, it may come into contact with the guide light module 102 along the pigtail, thereby affecting the normal operation of the guide light module 102. Therefore, the reflection module 104 also includes a pump light reflection module 115, which (e.g., Figure 6 As shown, a pump light reflection module 115 is disposed between the reflection module 104 and the wavelength division multiplexer 103 to reflect the pump beam that is not absorbed by the gain fiber. The pump light reflection module 115 can be a reflective pump wavelength grating with a reflectivity of 99.5%.

[0066] Figure 7 This is a schematic diagram of the optical path of a fiber laser provided in another embodiment of the present invention. Optionally, as shown... Figure 7 As shown, the resonant cavity 101 also includes a Q switch 116, which is located between the first fiber Bragg grating 109 and the first gain fiber 108.

[0067] It is understandable that when the wavelength division multiplexer 103 is located inside the resonant cavity 1011, the Q switch 116 can connect the first fiber Bragg grating 109 to the wavelength division multiplexer 103, or connect the wavelength division multiplexer 103 to the first gain fiber 108. When the wavelength division multiplexer 103 is located between the resonant cavity 1011 and the amplification stage 1012, the Q switch 116 connects the first fiber Bragg grating 109 to the first gain fiber 108 (e.g., ...). Figure 7 (As shown).

[0068] The addition of Q switch 116 enables the acquisition of pulsed laser light to adapt to different processing methods of workpiece 105.

[0069] Figure 8 This is a schematic diagram of the optical path of a fiber laser provided in another embodiment of this utility model; Figure 9 This is a schematic diagram of the optical path of a fiber laser provided in another embodiment of the present invention. Optionally, as shown... Figures 5 to 9 As shown, the amplification stage 1012 of the laser module 101 includes a second pump unit 111, a second fiber combiner 113, and a second gain fiber 114.

[0070] One side of the second fiber combiner 113 is used to connect the output end of the resonant cavity 1011 of the second pump unit 111 and the laser module 101, and the other side is used to connect the second gain fiber 114. The other end of the second gain fiber 114 is used to output the laser beam and the guide beam.

[0071] Among them, such as Figures 5 to 7 As shown, wavelength division multiplexer 103 is located inside resonant cavity 1011. Consequently, the main oscillation stage beam output from resonant cavity 1011 is mixed with the guide beam. Then, the main oscillation stage beam and the guide beam simultaneously enter amplification stage 1012, and after being amplified by the second gain fiber 114, they are output and simultaneously act on the workpiece 105.

[0072] like Figure 8 and Figure 9 As shown, the wavelength division multiplexer 103 is located between the resonant cavity 1011 and the amplification stage 1012. The main oscillation stage beam output from the resonant cavity 1011 is mixed with the guide beam and then simultaneously enters the amplification stage 1012. After being amplified by the second gain fiber 114, it is output and simultaneously acts on the workpiece 105. Figure 9In the example, a pump light reflection module 115 was also added to prevent the pump light from the second pump unit 111 from affecting the guide light module 102. A Q switch 116 was also added to form a pulsed laser.

[0073] In another embodiment, the amplification stage 1012 may also include a third pumping unit 112.

[0074] A coiled module can also be set in the reflection module 104 to be used in conjunction with the two gratings (i.e., pump light reflection module 115 and processing light reflection module 1041). For example, when processing materials, a photochemical reaction occurs, producing light other than signal light (1064nm) and pump light (915nm).

[0075] In the above embodiments, the first fiber combiner 107 is a (1+1)*1 combiner, and the second fiber combiner 113 is a (1+2)*1 combiner. The first gain fiber 108 and the second gain fiber 114 can be solid-state gain media (Nd:YAG, Yb:YAG, TiO2, etc.). The periods of the first fiber Bragg grating 109 and the second fiber Bragg grating 110 are mainly determined by the first pump beam output by the first pump unit 106. The pump light reflection module 115 determines the corresponding return pump light, which is also a fiber Bragg grating, according to the position of the wavelength division multiplexer 103.

[0076] According to another aspect of the present invention, an embodiment of the present invention also provides a laser processing device, including a fiber laser as described in any embodiment of the present invention.

[0077] The laser processing equipment can achieve the same effects as the fiber laser described in any embodiment of this utility model.

[0078] Taking red light as the guide light as an example, with a wavelength of approximately 633nm, a reflection module 104 is set up. This module includes a processing light reflection module 1041 and a pump light reflection module 115. Except for the processing light wavelength used by the fiber laser, light of other wavelengths is almost unaffected by the fiber Bragg grating (reflection module 104). This significantly increases the damage threshold of the red indicator light source and ensures that its output power geometry remains unaffected. Furthermore, it avoids damage to the red light source from the processing return signal light, ensuring the output power of the red indicator light source, reducing the probability of damage to the red indicator light, thereby extending the lifespan of the fiber laser and saving costs.

[0079] The technical solution of this utility model embodiment includes a laser module for outputting a laser beam, a guide beam module for outputting a guide beam, a wavelength division multiplexer for connecting the laser module and the guide beam module, and a reflection module located between the guide beam module and the wavelength division multiplexer. The wavelength division multiplexer combines the laser beam and the guide beam, and guides the laser beam to process the workpiece using the guide beam. The reflection module is used to reflect the reflected light beam generated during the processing of the workpiece. Furthermore, the reflection module in this application can reflect the reflected light, preventing the reflected light generated by highly reflective materials during engraving from entering the laser's interior along the laser output port and damaging the internal red light source. In other words, the reflection module can reduce the impact of the reflected light on the guide beam module, thereby improving the performance of the guide beam module.

[0080] It should be understood that the various forms of the process shown above can be used to rearrange, add, or delete steps. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0081] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A fiber laser, characterized in that, include: Laser module, used to output laser beam; The guide light module is used to output a guide light beam; A wavelength division multiplexer is used to connect the laser module and the guide light module, and to combine the laser beam and the guide light beam; A reflection module is disposed between the guide light module and the wavelength division multiplexer, and the reflection module is used at least to reflect the return light beam formed when the laser beam processes the workpiece.

2. The fiber laser according to claim 1, characterized in that, The reflection module includes a processing light reflection module. The period of the processing light reflection module is determined by the wavelength of the return light beam and the effective refractive index of the processing light reflection module. The processing light reflection module is also used to ensure that the difference between the output power of the guide light module and the working power of the guide light beam is within a preset range. The processing light reflection module is a fiber Bragg grating.

3. The fiber laser according to claim 1, characterized in that, The laser module includes a resonant cavity and an amplification stage; The wavelength division multiplexer is located inside the resonant cavity, or between the resonant cavity and the amplification stage.

4. The fiber laser according to claim 3, characterized in that, When the output power of the resonant cavity is greater than or equal to the damage threshold of the wavelength division multiplexer, and the power inside the resonant cavity is less than the damage threshold of the wavelength division multiplexer, the wavelength division multiplexer is located inside the resonant cavity; When the output power of the resonant cavity is less than the damage threshold of the wavelength division multiplexer, and the power inside the resonant cavity is greater than the damage threshold of the wavelength division multiplexer, the wavelength division multiplexer is located between the resonant cavity and the amplification stage.

5. The fiber laser according to claim 1, characterized in that, The laser module further includes a first pump unit, a first gain fiber, and a resonant cavity. The resonant cavity includes a first fiber Bragg grating and a second fiber Bragg grating for relative reflection. The output of the first pump unit is connected to the resonant cavity via an optical fiber combiner, and the first gain fiber is disposed inside the resonant cavity; When the wavelength division multiplexer is located inside the resonant cavity, the first end of the wavelength division multiplexer is connected to the first fiber Bragg grating, the second end is connected to the first gain fiber, and the third end is connected to the return beam input end of the reflection module. When the wavelength division multiplexer is located between the resonant cavity and the amplification stage of the laser module, the first end of the wavelength division multiplexer is connected to the output end of the resonant cavity, the second end is connected to the amplification stage, and the third end is connected to the return beam input end of the reflection module.

6. The fiber laser according to claim 5, characterized in that, The resonant cavity also includes a Q switch, which is located between the first fiber Bragg grating and the first gain fiber.

7. The fiber laser according to claim 1, characterized in that, The amplification stage of the laser module includes a second pump unit, a second fiber combiner, and a second gain fiber. One side of the second fiber combiner is used to connect the output end of the resonant cavity of the second pump unit and the laser module, and the other side is used to connect the second gain fiber. The other end of the second gain fiber is used to output the laser beam and the guide beam.

8. The fiber laser according to claim 1, characterized in that, The reflection module further includes a pump light reflection module, which is located between the processing light reflection module and the guide light module, or between the processing light reflection module and the wavelength division multiplexer. The pump light reflection module is a fiber Bragg grating.

9. The fiber laser according to claim 1, characterized in that, The guiding light module is one of the following: red light source, green light source, violet light source, or blue light source.

10. A laser processing apparatus comprising a fiber laser as described in any one of claims 1-9.

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