Fiber laser and its control method

Abstract

The present application provides an optical fiber laser and a control method therefor. The optical fiber laser includes a laser module, a detection module, an output module, and a control module. The laser module, the detection module, and the output module are sequentially connected along the optical fiber laser, and the control module is connected to the laser module and the detection module respectively. The laser module is configured to generate a laser beam and output the laser beam to the detection module. The detection module is configured to filter out the non-linear light in the laser beam, generate a detection signal according to the non-linear light, and output the detection signal and the laser beam after filtering out the non-linear light to the control module and the output module respectively. The control module is configured to adjust the working parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module. The output module is configured to output the laser beam after filtering out the non-linear light to the outside. By filtering out and detecting the non-linear light in the laser beam, the non-linear effect in the optical fiber laser is improved and a feedback protection mechanism is established.

Description

Technical Field

[0001] This application belongs to the technical field of lasers, and particularly relates to an optical fiber laser and a control method thereof. Background Art

[0002] With the development of optical fiber lasers, the output power requirements of optical fiber lasers are getting higher and higher, which leads to more and more serious scattering phenomena in the optical fiber, greatly affecting the use of optical fiber lasers. In particular, it causes the deterioration of the emitted light and the enhancement of the return light of the optical fiber laser, resulting in poor processing effects. When the return light is serious during processing, it will burn out the optical fiber laser.

[0003] Therefore, the prior art has defects and needs to be improved and developed. Summary of the Invention

[0004] This application provides an optical fiber laser and a control method thereof, aiming to improve the nonlinear effect in the optical fiber laser and establish a feedback protection mechanism using nonlinear light at the same time.

[0005] To achieve the above object, this application provides an optical fiber laser, including a laser module, a detection module, an output module, and a control module. The laser module, the detection module, and the output module are sequentially connected along the optical path direction of the optical fiber laser, and the control module is respectively connected to the laser module and the detection module. Among them, the laser module is used to generate a laser beam and output the laser beam to the detection module; the detection module is used to filter out the nonlinear light in the laser beam, generate a detection signal according to the nonlinear light, and respectively output the detection signal and the laser beam after filtering out the nonlinear light to the control module and the output module; the control module is used to adjust the working parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module; the output module is used to output the laser beam after filtering out the nonlinear light outward.

[0006] Among them, the detection module includes a Raman suppression grating, a mode stripping fiber, and a photodetector. The mode stripping fiber includes a cladding and a core, and the mode stripping fiber includes a mode stripping area. The Raman suppression grating is respectively connected to the laser module and the mode stripping fiber, and is used to convert the nonlinear light in the laser beam to be transmitted in the cladding of the mode stripping fiber; the mode stripping fiber is also connected to the output module, and is used to overflow the nonlinear light transmitted in the cladding in the mode stripping area, and transmit the laser beam after filtering out the nonlinear light to the output module; the photodetector is connected to the control module, and is used to receive the nonlinear light, generate an electrical signal according to the nonlinear light, and transmit the electrical signal to the control module.

[0007] Wherein, the detection module further includes a base and a cover plate which are oppositely arranged. An optical fiber placement groove and a detector installation groove that communicate with each other are formed in the base. The Raman suppression grating is installed in the optical fiber placement groove. The stripping optical fiber passes through the detector installation groove and is installed in the optical fiber placement groove. The optical detector covers the surface of the detector installation groove.

[0008] Wherein, the optical detector is a carbon nanotube thin film.

[0009] Wherein, the laser module includes: a plurality of pump sources; a pump beam combiner connected to the plurality of pump sources for coupling the pump light generated by the plurality of pump sources; and a laser oscillator connected to the pump beam combiner for receiving the pump light coupled by the pump beam combiner and causing the coupled pump light to oscillate to generate a laser beam.

[0010] Wherein, the control module is connected to the plurality of pump sources in the laser module, and the control module is used to adjust the input power of the plurality of pump sources according to the detection signal.

[0011] Wherein, an isolation module is further arranged between the output module and the detection module, and the isolation module is used to isolate the return light in the output module.

[0012] Wherein, a signal threshold is also established in the control module. The control module is further used to compare the magnitudes of the detection signal and the signal threshold, and adjust the working parameters of the laser module according to the comparison result to control the power of the laser beam generated by the laser module.

[0013] This application also provides a control method for an optical fiber laser, which is applied to the optical fiber laser as described above. The method includes: obtaining a detection signal generated by the detection module, where the detection signal is generated according to the non-linear light in the laser beam generated by the laser module; and adjusting the working parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module.

[0014] Wherein, the step of adjusting the working parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module includes: obtaining a signal threshold; comparing the magnitudes of the detection signal and the signal threshold; and adjusting the working parameters of the laser module according to the comparison result to control the power of the laser beam generated by the laser module.

[0015] The beneficial effects of the present application are as follows: In the fiber laser provided by the present application, the detection module is used to filter out the non-linear light in the laser beam generated by the laser module, so as to avoid the existence of non-linear light in the laser beam output from the output module, thereby preventing the non-linear light from being reflected back and damaging the components inside the fiber laser. Additionally, the detection module generates a detection signal based on the non-linear light, and the control module adjusts the operating parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module, enabling the fully utilization of the filtered non-linear light. That is, by detecting the non-linear light, the fluctuations of the non-linear effect in the fiber laser can be fed back in real time, and the output power of the fiber laser can be adjusted according to the strength of the non-linear effect in the fiber laser. Thus, the fiber laser can output a laser beam with a higher power under the condition of a lower intensity of the scattered light caused by the non-linear effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the technical solutions of the present application, the accompanying drawings required for the description of each embodiment formed according to the present application will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 is a schematic structural diagram of a fiber laser provided by an embodiment of the present application;

[0018] Figure 2 is a schematic structural diagram of the detection module provided by an embodiment of the present application;

[0019] Figure 3 is a schematic structural diagram of another fiber laser provided by an embodiment of the present application;

[0020] Figure 4 is a schematic flowchart of a control method for a fiber laser provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0022] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is 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. Therefore, it should not be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0023] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0024] In the present application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0025] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0026] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a fiber laser provided by an embodiment of the present application. As Figure 1 shown, the fiber laser includes a laser module 10, a detection module 20, an output module 30, and a control module 40. The laser module 10, the detection module 20, and the output module 30 are sequentially connected along the optical path direction of the fiber laser. The control module 40 is respectively connected to the laser module 10 and the detection module 20. Among them, the laser module 10 is used to generate a laser beam and output the laser beam to the detection module 20. The detection module 20 is used to filter out the non-linear light in the laser beam, generate a detection signal according to the non-linear light, and respectively output the detection signal and the laser beam after filtering out the non-linear light to the control module 40 and the output module 30. The control module 40 is used to adjust the working parameters of the laser module 10 according to the detection signal to control the power of the laser beam generated by the laser module 10. The output module 30 is used to output the laser beam after filtering out the non-linear light to the outside.

[0027] In this embodiment, by using the detection module 20 to filter out the non-linear light in the laser beam generated by the laser module 10, it is avoided that there is still non-linear light in the laser beam output from the output module 30. That is to say, in this embodiment, before the non-linear light is reflected from the surface of the processed object into the fiber laser, it is filtered in advance, so as to avoid the non-linear light being reflected back and damaging the devices inside the fiber laser. In this embodiment, the detection module 20 is also used to generate a detection signal according to the non-linear light, and the control module 40 is used to adjust the working parameters of the laser module 10 according to the detection signal to control the power of the laser beam generated by the laser module 10, so that the filtered non-linear light is fully utilized. That is, by detecting the non-linear light, the fluctuation of the non-linear effect in the fiber laser can be fed back in real time, and the output power of the fiber laser can be adjusted according to the strength of the non-linear effect in the fiber laser. Thus, the fiber laser can output a laser beam with a higher power under the condition that the intensity of the scattered light caused by the non-linear effect is relatively low.

[0028] In this embodiment, the operating state of the laser module 10 is directly tested during the operation of the fiber laser. By the fluctuations of the nonlinear effect, possible faults can be predicted in advance before the fiber laser fails, so as to give an alarm before the fiber laser fails or the output light spot deteriorates, ensuring the processing effect.

[0029] Among them, a signal threshold is also established in the control module 40. The control module 40 is also used to compare the magnitude of the detection signal and the signal threshold, and adjust the operating parameters of the laser module 10 according to the comparison result to control the power of the laser beam generated by the laser module 10.

[0030] Specifically, when the detection signal is greater than the signal threshold, the operating parameters of the laser module 10 are adjusted to reduce the power of the laser beam generated by the laser module 10, so that the intensity of the scattered light brought by the overall nonlinear effect of the fiber laser decreases; when the detection signal weakens, the output power of the fiber laser is increased again to make the fiber laser resume working at high power.

[0031] Please continue to refer to Figure 1 , where the laser module 10 includes a pump combiner 12, a laser oscillator 13, and a plurality of pump sources 11. The pump combiner 12 is connected to the plurality of pump sources 11 and is used for coupling the pump light generated by the plurality of pump sources 11. The laser oscillator 13 is connected to the pump combiner 12 and is used for receiving the pump light coupled by the pump combiner 12 and causing the coupled pump light to oscillate to generate a laser beam.

[0032] Specifically, the laser module 10 further includes a plurality of single-core optical fibers, and the plurality of single-core optical beams correspond to the plurality of pump sources 11 one by one. Each pump source 11 in the plurality of pump sources 11 is connected to a corresponding single-core optical fiber, and the plurality of single-core optical fibers are connected to the pump combiner 12. Each pump source 11 in the plurality of pump sources 11 is used for generating pump light in the corresponding single-core optical fiber, and transmitting the pump light to the pump combiner 12 by the corresponding single-core optical fiber.

[0033] Specifically, the laser oscillator 13 includes a high-reflection grating 131, a low-reflection grating 133, and a gain optical fiber 132, and the gain optical fiber 132 is connected between the high-reflection grating 131 and the low-reflection grating 133.

[0034] Among them, the control module 40 is connected to the plurality of pump sources 11 in the laser module 10, and the control module 40 is used for adjusting the input power of the plurality of pump sources 11 according to the detection signal.

[0035] Specifically, by adjusting the input power of the pump source 11, the power of the pump light generated by the pump source 11 and the power of the laser beam related to the pump light are also adjusted, so as to achieve the effect of controlling the power of the laser beam generated by the laser module 10 by adjusting the working parameters of the laser module 10.

[0036] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of the detection module provided by an embodiment of the present application. As Figure 2 shown, the detection module 20 includes a Raman suppression grating 21, a mode stripping fiber 22 and a photodetector 23. The mode stripping fiber 22 includes a cladding and a core (not shown in the figure), and the mode stripping fiber 22 includes a mode stripping region 222. The Raman suppression grating 21 is respectively connected to the laser module 10 and the mode stripping fiber 22, and is used to convert the non-linear light in the laser beam into the cladding of the mode stripping fiber 22 for transmission. The mode stripping fiber 22 is also connected to the output module 30, and is used to overflow the non-linear light transmitted in the cladding in the mode stripping region 222, and transmit the laser beam filtered from the non-linear light to the output module 30. The photodetector 23 is connected to the control module 40, and is used to receive the non-linear light, generate an electrical signal according to the non-linear light, and transmit the electrical signal to the control module 40.

[0037] Specifically, the mode stripping fiber 22 further includes a bare fiber region 221, and the bare fiber regions 221 are distributed on opposite sides of the mode stripping region 222. The coating layer of the bare fiber region 221 has been removed, and the inner cladding surface in the bare fiber region 221 is respectively subjected to mechanical etching and chemical etching, so that the inner cladding surface presents a rough or textured state, forming the mode stripping region 222.

[0038] As Figure 2 shown, the detection module 20 further includes a base 24 and a cover plate 25 which are oppositely arranged. A fiber placement groove 242 and a detector installation groove 241 which communicate with each other are formed in the base 24. The Raman suppression grating 21 is installed in the fiber placement groove 242, the mode stripping fiber 22 passes through the detector installation groove 241 and is installed in the fiber placement groove 242, and the photodetector 23 covers the surface of the detector installation groove 241.

[0039] Specifically, the mode stripping fiber 22 and the Raman suppression grating 21 are fixed on the surface of the fiber placement groove 242 by gluing. Wires (not shown in the figure) are also connected to both ends of the photodetector 23. The wires extend outward through the fiber placement groove 242 to be connected to the control module 40, and the photodetector 23 transmits a detection signal to the control module 40 through the wires.

[0040] In other embodiments, the Raman suppression grating 21 can also be disposed in the core of the stripping region 222, so that while converting the non-linear light in the laser beam into the cladding of the stripping optical fiber 22 for transmission, the non-linear light overflows from the stripping optical fiber 22.

[0041] In one embodiment, the optical detector 23 is a carbon nanotube film, and the base 24 and the cover plate 25 are made of metal. When the optical detector 23 is selected as the carbon nanotube film, firstly, by utilizing the characteristic that the carbon nanotube film absorbs light and is converted into current, the optoelectronic conversion response time is greatly reduced, and the detection efficiency is improved. Secondly, the high thermal conductivity of the carbon nanotube film itself and the cooperation with the metal base 24 and cover plate 25 greatly improve the heat dissipation efficiency of the non-linear light. Finally, since the thickness of the carbon nanotube film itself is relatively thin, it is beneficial to reduce the thickness of the optical detector 23, thereby indirectly facilitating the miniaturization of the detection module 20.

[0042] Please refer to Figure 3 , Figure 3 FIG. is a schematic structural diagram of another fiber laser provided by an embodiment of the present application. Among them, an isolation module 50 is further disposed between the output module 30 and the detection module 20. The isolation module 50 is used to isolate the return light in the output module 30 to prevent the return light from damaging other devices in the fiber laser.

[0043] Please refer to Figure 4 , Figure 4 FIG. is a schematic flow chart of a control method for a fiber laser provided by the present application, which is applied to the fiber laser as described above. As Figure 4 shown, the method includes:

[0044] Step S41: Obtain a detection signal generated by the detection module. The detection signal is generated according to the non-linear light in the laser beam generated by the laser module;

[0045] Step S42: According to the detection signal, adjust the working parameters of the laser module to control the power of the laser beam generated by the laser module.

[0046] In one embodiment, step S42 further includes:

[0047] Obtain a signal threshold;

[0048] Compare the magnitudes of the detection signal and the signal threshold;

[0049] According to the comparison result, adjust the working parameters of the laser module to control the power of the laser beam generated by the laser module.

[0050] In the control method provided in this embodiment, the operating parameters of the laser module are adjusted according to the detection signal to control the power of the laser beam generated by the laser module, so that the non-linear light to be filtered is fully utilized. That is, by detecting the non-linear light, the fluctuations of the non-linear effect in the fiber laser can be fed back in real time, and the output power of the fiber laser can be adjusted according to the strength of the non-linear effect in the fiber laser. Thus, the fiber laser can output a laser beam with a higher power under the condition that the intensity of the scattered light caused by the non-linear effect is relatively low.

[0051] The above has introduced in detail a fiber laser and its control method provided by an embodiment of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. At the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application. Moreover, for those of ordinary skill in the art of this technology, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present application.

Claims

1. An optical fiber laser, characterized in that, It includes a laser module, a detection module, an output module and a control module. The laser module, the detection module and the output module are sequentially connected along the optical path direction of the fiber laser, and the control module is respectively connected to the laser module and the detection module; wherein, The laser module is used to generate a laser beam and output the laser beam to the detection module; The detection module is used to filter out the non-linear light in the laser beam, generate a detection signal according to the non-linear light, and respectively output the detection signal and the laser beam after filtering out the non-linear light to the control module and the output module; The control module is used to adjust the working parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module; The output module is used to output the laser beam after filtering out the non-linear light to the outside.

2. The fiber laser according to claim 1, characterized in that, The detection module includes a Raman suppression grating, a mode stripping fiber and a photodetector. The mode stripping fiber includes a cladding and a core, and the mode stripping fiber includes a mode stripping area; The Raman suppression grating is respectively connected to the laser module and the mode stripping fiber, and is used to convert the non-linear light in the laser beam into the cladding of the mode stripping fiber for transmission; The mode stripping fiber is also connected to the output module, and is used to overflow the non-linear light transmitted in the cladding in the mode stripping area, and transmit the laser beam after filtering out the non-linear light to the output module; The photodetector is connected to the control module, and is used to receive the non-linear light, generate an electrical signal according to the non-linear light, and transmit the electrical signal to the control module.

3. The fiber laser according to claim 2, characterized in that, The detection module further includes a base and a cover plate arranged oppositely. The base is provided with a fiber placement groove and a detector installation groove that communicate with each other. The Raman suppression grating is installed in the fiber placement groove, and the mode stripping fiber passes through the detector installation groove and is installed in the fiber placement groove. The photodetector covers the surface of the detector installation groove.

4. The fiber laser according to claim 3, characterized in that, The photodetector is a carbon nanotube film.

5. The fiber laser according to claim 1, wherein The laser module includes: Multiple pump sources; A pump combiner, connected to the multiple pump sources, and used to couple the pump light generated by the multiple pump sources; A laser oscillator, connected to the pump combiner, and used to receive the pump light coupled by the pump combiner, and make the coupled pump light oscillate to generate a laser beam.

6. The fiber laser according to claim 5, characterized in that, The control module is connected to the multiple pump sources in the laser module, and the control module is used to adjust the input power of the multiple pump sources according to the detection signal.

7. The fiber laser according to claim 1, characterized in that An isolation module is further provided between the output module and the detection module, and the isolation module is used to isolate the return light in the output module.

8. The fiber laser according to claim 1, characterized in that, A signal threshold is also established in the control module. The control module is further used to compare the magnitudes of the detection signal and the signal threshold, and adjust the working parameters of the laser module according to the comparison result to control the power of the laser beam generated by the laser module.

9. A control method for a fiber laser, characterized in that, Applied to the fiber laser according to any one of claims 1 to 8, the method includes: Obtain the detection signal generated by the detection module, where the detection signal is generated based on the non-linear light in the laser beam generated by the laser module; According to the detection signal, adjust the operating parameters of the laser module to control the power of the laser beam generated by the laser module.

10. The control method of the fiber laser according to claim 9, wherein The step of adjusting the operating parameters of the laser module according to the detection signal to control the power of the laser beam generated by the laser module includes: Obtain a signal threshold; Compare the magnitudes of the detection signal and the signal threshold; According to the comparison result, adjust the operating parameters of the laser module to control the power of the laser beam generated by the laser module.

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