Fiber laser and reflected light power detection and protection method

Abstract

The invention discloses an optical fiber laser and a reflected light power detection protection method, and relates to the technical field of laser equipment, the optical fiber laser comprises a seed source, a band-pass isolator, a main amplifier and a detection assembly, the seed source, the band-pass isolator and the main amplifier are connected in sequence, and the band-pass isolator is provided with a first output port; the detection assembly comprises a beam splitting part, a cladding light stripping part and a detection part, the beam splitting part is connected with the first output port, the cladding light stripping part is connected with the beam splitting part, and the detection part is arranged on the cladding light stripping part and is in electric signal connection with the seed source; the band-pass isolator is used for isolating the reflected light and coupling the reflected light to the beam splitter through the first output port; and the detection part is used for detecting the reflected light signal stripped by the cladding light stripping part. According to the technical scheme provided by the invention, the technical problem of poor adaptation of the fiber laser in use can be solved.

Description

Technical Field

[0001] This invention relates to the field of laser equipment technology, and in particular to a fiber laser and a method for detecting and protecting the power of reflected light. Background Technology

[0002] Fiber lasers are a special type of laser that uses a semiconductor laser as a pump source. Light of a specific wavelength is injected into an optical fiber, exciting doped ions to produce stimulated emission. This emission is then amplified and fed back through fiber optic resonators at both ends of the fiber, ultimately resulting in a high-brightness, high-power laser output. Due to their flexible fiber structure, they offer significant advantages such as excellent heat dissipation, high energy conversion efficiency, superior beam quality, and compact design, making them widely used in industrial processing, communications, medical, and military fields. However, fiber lasers suffer from poor adaptability in practical applications.

[0003] Therefore, it is necessary to provide a new fiber laser and a method for detecting and protecting reflected light power to solve the above-mentioned technical problems. Summary of the Invention

[0004] The main objective of this invention is to provide a fiber laser and a method for detecting and protecting its reflected light power, aiming to solve the technical problem of poor adaptability in the use of fiber lasers.

[0005] To achieve the above objectives, the present invention proposes a fiber laser, comprising a seed source, a bandpass isolator, a main amplifier, and a detection component, wherein the seed source, the bandpass isolator, and the main amplifier are connected in sequence, and the bandpass isolator is provided with a first output port; The detection component includes a beam splitter, a cladding stripper, and a detection element. The beam splitter is connected to the first output port, the cladding stripper is connected to the beam splitter, and the detection element is disposed on the cladding stripper and electrically connected to the seed source and the main amplifier. The bandpass isolator is used to isolate the reflected light and couple the reflected light to the beam splitter through the first output port. The detection element is used to detect the power of the reflected light stripped by the cladding stripper.

[0006] In one embodiment, the beam splitter has a second output port and a third output port. The second output port is connected to the cladding stripper via an optical fiber, and the third output port is connected to a power meter, which is electrically connected to the detection device.

[0007] In one embodiment, the beam splitter is used to split the light; the beam splitter is used to output a portion of the reflected light to the cladding stripper through the second output port, and to output another portion of the reflected light to the power meter through the third output port; Definition: Let a be the power of the reflected light output from the beam splitter to the cladding stripper, and b be the power of the reflected light output from the beam splitter to the power meter; then a < b.

[0008] In one embodiment, the ratio of the power of the reflected light output from the beam splitter to the cladding stripper and the power of the reflected light output from the beam splitter to the power meter should satisfy a:b = 5%:95%~15%:85%.

[0009] In one embodiment, the ratio of the power of the reflected light output from the beam splitter to the cladding stripper and the power of the reflected light output from the beam splitter to the power meter is a:b = 10%:90%.

[0010] In one embodiment, the fiber laser further includes a first amplifier and a second amplifier, which are sequentially connected between the seed source and the bandpass isolator.

[0011] In one embodiment, the bandpass isolator is a three-port bandpass isolator, which also has an input port and a fourth output port. The input port is connected to the second amplifier, and the fourth output port is connected to the main amplifier.

[0012] In one embodiment, the cladding light filter is provided with a light-transmitting hole, and the detection element is disposed at the light-transmitting hole.

[0013] In addition, the present invention also proposes a method for detecting and protecting reflected light power, applied to the aforementioned fiber laser, wherein the method for detecting and protecting reflected light power includes: Control the seed source to emit signal light; Control the bandpass isolator to isolate the reflected light and couple the reflected light to the beam splitter; The beam splitter controls the output of the reflected light to the cladding stripper; The control detection device detects the reflected light signal stripped by the cladding light stripper, and controls the seed source and main amplifier to shut down when the actual power of the reflected light exceeds a preset threshold.

[0014] In one embodiment, the step of controlling the beam splitter to output the reflected light to the cladding stripper includes: The beam splitter is controlled to output a portion of the reflected light to the cladding light stripper and another portion of the reflected light to the power meter; wherein the ratio of the power of the reflected light output by the beam splitter to the cladding light stripper and the power of the reflected light output by the beam splitter to the power meter is 1:9. The power meter is controlled to detect the reflected light it receives, and a correspondence is established between the reading of the detection device and the actual power of the reflected light. The step of controlling the detection device to detect the reflected light signal stripped by the cladding stripper, and controlling the seed source to shut down when the actual power of the reflected light exceeds a preset threshold, includes: The control detector detects the reflected light signal stripped by the cladding stripper, and based on the detection data of the detector and the corresponding relationship, determines whether the actual power of the reflected light exceeds a preset threshold; if so, the seed source and the main amplifier are turned off.

[0015] The technical solution of this invention, by setting a bandpass isolator in the fiber laser to isolate back-reflected light and setting a detection device to detect the power of the back-reflected light, can promptly shut down the seed source and main amplifier when the actual power of the back-reflected light exceeds a preset threshold, thus preventing damage to the fiber laser. This fiber laser, capable of real-time detection of the actual power of the back-reflected light during use, effectively solves the technical problem of poor adaptability in fiber laser operation. In this embodiment, the seed source provides high-quality, narrow-linewidth signal light, serving as the signal light emission source of the fiber laser. The bandpass isolator transmits the forward signal light, filters out other wavelengths outside the bandpass, and isolates and couples the back-reflected light to the beam splitter. The beam splitter outputs a portion of the back-reflected light to the cladding stripper. The cladding stripper strips the back-reflected light input to the beam splitter, effectively stripping the optical signal transmitted within the fiber cladding. The detection device detects the back-reflected light signal stripped by the cladding stripper. This fiber laser, by incorporating a bandpass isolator, beam splitter, cladding stripper, and detection unit, can detect the actual power of the reflected light in real time. This enhances the fiber laser's applicability and prevents damage during use. Specifically, after the detection unit detects the reflected light signal stripped by the cladding stripper, the controller determines whether the actual power of the reflected light exceeds a preset threshold using the following correlation. If it exceeds the preset threshold, the controller shuts down the seed source and main amplifier to protect the fiber laser and prevent damage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the connection of a fiber laser in one embodiment of the present invention; Figure 2 A schematic flowchart of a retroreflection power detection and protection method in one embodiment of the present invention; Figure 3 A schematic flowchart of a retroreflective power detection and protection method in another embodiment of the present invention.

[0018] Explanation of icon numbers: 100, Seed source; 200, Bandpass isolator; 300, Main amplifier; 400, Detector assembly; 410, Beam splitter; 411, Power meter; 420, Cladding stripper; 430, Detector; 500, First amplifier; 600, Second amplifier.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] Furthermore, if the embodiments of the present invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously.

[0023] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0024] Fiber lasers are a special type of laser that uses a semiconductor laser as a pump source. Light of a specific wavelength is injected into an optical fiber, exciting doped ions to produce stimulated emission. This emission is then amplified and fed back through fiber optic grating resonators at both ends of the fiber, ultimately resulting in a high-brightness, high-power laser output. During actual production and research, researchers have discovered that stimulated Brillouin scattering (SBS), a significant nonlinear effect in optical fibers, generates back-propagating Stokes light (hereinafter referred to as retroreflection), which can damage fiber lasers. Traditionally, to control stimulated Brillouin scattering and prevent damage from excessive retroreflection, the power of the retroreflection is measured during power tuning to determine the safe threshold range of the fiber laser. The laser is then operated within this safe threshold range during use. In other words, the traditional approach is to determine the safe threshold range of the fiber laser through testing and operate it within that range to avoid damage. However, this approach cannot dynamically address the threshold changes in stimulated Brillouin scattering caused by light emission time and usage environment, which exposes the technical problem of poor adaptability of fiber lasers during use.

[0025] This invention proposes a fiber laser and a method for detecting and protecting its reflected light power, aiming to solve the technical problem of poor adaptability in the use of fiber lasers.

[0026] Please see Figure 1 In one embodiment of the present invention, the fiber laser includes a seed source 100, a bandpass isolator 200, a main amplifier 300, and a detection component 400. The seed source 100, the bandpass isolator 200, and the main amplifier 300 are connected in sequence. The bandpass isolator 200 is provided with a first output port. The detection component 400 includes a beam splitter 410, a cladding light stripper 420, and a detection component 430. The beam splitter 410 is connected to the first output port, the cladding light stripper 420 is connected to the beam splitter 410, and the detection component 430 is disposed on the cladding light stripper 420 and electrically connected to the seed source 100 and the main amplifier 300. The bandpass isolator 200 is used to isolate the reflected light and couple the reflected light to the beam splitter 410 through the first output port. The detection component 430 is used to detect the reflected light signal stripped by the cladding light stripper 420.

[0027] The technical solution of this invention, by setting a bandpass isolator 200 for isolating back-reflected light in the fiber laser and setting a detection device 430 for detecting the power of the back-reflected light, can promptly shut down the seed source 100 and the main amplifier 300 when the actual power of the back-reflected light exceeds a preset threshold, thus preventing damage to the fiber laser. This fiber laser, capable of real-time detection of the actual power of the back-reflected light during use, effectively solves the technical problem of poor adaptability in fiber laser operation. In this embodiment, the seed source 100 provides high-quality, narrow-linewidth signal light, serving as the signal light emission source of the fiber laser. The bandpass isolator 200 transmits forward signal light, filters out other wavelengths outside the bandpass, isolates back-reflected light, and couples the back-reflected light to the beam splitter 410. The beam splitter 410 outputs a portion of the back-reflected light to the cladding stripper 420. The cladding light stripper 420 is used to strip the reflected light input from the beam splitter 410, that is, to strip the optical signal transmitted in the fiber cladding. This improves the accuracy of the detection unit 430 in detecting the reflected light signal stripped by the cladding light stripper 420. The detection unit 430 is used to detect the reflected light signal stripped by the cladding light stripper 420. By incorporating the bandpass isolator 200, beam splitter 410, cladding light stripper 420, and detection unit 430, this fiber laser can detect the true power of the reflected light in real time, improving its applicability and preventing damage during use. Specifically, after the detection unit 430 detects the reflected light signal stripped by the cladding light stripper 420, the controller can determine whether the true power of the reflected light exceeds a preset threshold using the following correspondence. If it exceeds the preset threshold, the controller can shut down the seed source 100 and the main amplifier 300 to protect the fiber laser and prevent damage. This fiber laser is used in high-quality, narrow-linewidth fiber lasers.

[0028] In a specific embodiment, the beam splitter 410 can be an optical fiber beam splitter, the detection element 430 can be a photodetector, and the cladding light stripping element 420 can be a cladding light stripper. The optical fiber beam splitter is a passive optical device used to split an input optical signal into two or more outputs according to a predetermined ratio; specifically, the optical fiber beam splitter can be a fused biconical taper type or a planar waveguide type. The photodetector is a semiconductor device that converts optical signals into electrical signals; in this embodiment, the photodetector detects the scattered light signal generated after the reflected light is stripped away by the cladding light stripping element 420. The cladding light stripping element 420 is used to strip away the reflected light input to the beam splitter 410, that is, to strip away the optical signal transmitted in the optical fiber cladding.

[0029] Please see Figure 1In one embodiment of the present invention, the beam splitter 410 has a second output port and a third output port. The second output port is connected to the cladding light stripper 420 via an optical fiber, and the third output port is connected to a power meter 411. The power meter 411 is electrically connected to the detection device 430. In this embodiment, the power meter 411 is used to detect the true power of the reflected light during debugging and to provide a debugging reference for the detection device 430. Specifically, during the debugging phase, the power meter 411 can establish a correspondence between the reading of the detection device and the true power of the reflected light. During use, the controller can determine whether the true power of the reflected light exceeds a preset threshold based on the above correspondence and the detection signal of the detection device 430. When the true power of the reflected light exceeds the preset threshold, the controller controls the seed source 100 and the main amplifier 300 to be turned off. It should be noted that when the detection element 430 detects the reflected light signal stripped by the cladding light stripper 420, it can only output a current or voltage signal, but the signal itself cannot directly reflect the true power of the reflected light. However, by establishing the correspondence between the reading of the detection element and the true power of the reflected light through the power meter 411, an accurate and reliable action threshold can be set for the photodetector.

[0030] In one embodiment of the present invention, the beam splitter 410 is used for beam splitting; the beam splitter 410 is used to output a portion of the reflected light to the cladding light stripper 420 through the second output port, and to output another portion of the reflected light to the power meter 411 through the third output port; defined as: the power of the reflected light output by the beam splitter 410 to the cladding light stripper 420 is a, and the power of the reflected light output by the beam splitter 410 to the power meter 411 is b; then: a < b. In this embodiment, by outputting most of the reflected light power to the power meter 411 through the beam splitter 410, the power meter 411 can be ensured to perform accurate and stable measurements. By outputting a small portion of the reflected light power to the cladding light stripper 420 through the beam splitter 410, and then to the detection device 430, the power of the reflected light can be attenuated to a range within which the detection device 430 can operate safely and linearly, thereby ensuring the accuracy of the detection data of the detection device 430 and avoiding damage to the detection device 430.

[0031] In one embodiment of the present invention, the ratio of the power of the reflected light output from the beam splitter 410 to the cladding stripper 420 and the power of the reflected light output from the beam splitter 410 to the power meter 411 should satisfy a:b = 5%:95% to 15%:85%. In this embodiment, by setting the ratio of the output from the beam splitter 410 to the cladding stripper 420 and to the power meter 411 to 5%:95% to 15%:85%, the optimal balance between system robustness and economy can be achieved. This ensures that the reflected light power output to the power meter 411 is always sufficiently strong to support the accuracy and stability of the power meter 411 measurement during the commissioning phase. At the same time, the reflected light power guided to the branch of the detection element 430 is strictly limited within a safe window. This ensures that the detection element 430 generates a clear and interference-resistant electrical signal and prevents damage to the detection element 430, ensuring that the detection element 430 operates within the linear range. In a specific embodiment, the ratio of the power of the reflected light output from the beam splitter 410 to the cladding stripper 420 and the power of the reflected light output from the beam splitter 410 to the power meter 411 is a:b = 10%:90%. That is, the beam splitting ratio of the beam splitter 410 is 1:9. Accordingly, in actual manufacturing, beam splitters 410 with different splitting ratios can be selected according to the sensitivity of the detection element 430, i.e., the sensitivity of the photodetector, to achieve compatibility with multiple sensors and facilitate detection.

[0032] Please see Figure 1 In one embodiment of the present invention, the fiber laser further includes a first amplifier 500 and a second amplifier 600, which are sequentially connected between the seed source 100 and the bandpass isolator 200. The bandpass isolator 200 is a three-port bandpass isolator, which also has an input port and a fourth output port. The input port is connected to the second amplifier 600, and the fourth output port is connected to the main amplifier 300. In this embodiment, by setting the first amplifier 500 and the second amplifier 600, they can form a main oscillation power amplification structure with the main amplifier 300. The purpose is to amplify the signal light emitted by the seed source 100 to a high power of kilowatt level in a step-by-step and controllable manner, while maximizing the preservation of the excellent characteristics of the signal light emitted by the seed source 100 and suppressing nonlinear effects. The first amplifier 500 is used to amplify the signal light emitted by the seed source 100 to the watt level, the second amplifier 600 is used to amplify the signal light emitted by the seed source 100 to the several watt level, and the main amplifier 300 is used to realize the final energy injection and output.

[0033] In one embodiment of the present invention, the cladding optical filter is provided with a light-transmitting hole, and the detection element 430 is disposed at the light-transmitting hole. In this embodiment, the detection element 430 is directly disposed at the light-transmitting hole of the cladding optical filter, which can avoid false protection caused by changes in optical signal due to fiber jitter.

[0034] In this embodiment of the fiber laser, all components are connected by optical fibers. In a specific embodiment, the seed source 100 is used to output a narrow-linewidth signal light with an output power of 10mW and a linewidth of 0.1nm. The first amplifier 500 is used to amplify the signal light to 0.6W, and the second amplifier 600 amplifies the signal light to 55W via a bandpass isolator 200. The seed source 100, the first amplifier 500, and the cladding filter all use optical fibers with a core diameter of 10μm and a cladding diameter of 125μm. The second amplifier 600, the bandpass isolator 200, and the main amplifier 300 all use optical fibers with a core diameter of 20μm and a cladding diameter of 400μm. The beam splitter 410 uses optical fibers with a core diameter of 105μm and a cladding diameter of 125μm. Furthermore, the beam splitting ratio of the beam splitter 410 is 1:9.

[0035] Please see Figure 2 , Figure 2 This is a schematic flowchart of a back-reflection power detection and protection method according to an embodiment of the present invention. The present invention also proposes a back-reflection power detection and protection method applied to the aforementioned fiber laser. This back-reflection power detection and protection method includes: S100 controls the seed source 100 to emit signal light; S200 controls the bandpass isolator 200 to isolate the backlight and couple the backlight to the beam splitter 410; S300, the beam splitter 410 controls the output of the reflected light to the cladding light stripper 420; S400 and the control detection unit 430 detect the reflected light signal stripped by the cladding light stripper 420, and when the actual power of the reflected light exceeds a preset threshold, control the seed source 100 and the main amplifier 300 to shut down. When controlling the seed source 100 and the main amplifier 300 to shut down, the first amplifier 500 and the second amplifier 600 must be shut down simultaneously.

[0036] Specifically, this retroreflection power detection and protection method shuts down the seed source 100, main amplifier 300, first amplifier 500, and second amplifier 600 when the actual power of the retroreflection exceeds a preset threshold; this better protects the fiber laser and improves its applicability. In a specific embodiment, a power meter 411 can be used as the detection element 430, and the controller can obtain the actual power of the retroreflection by acquiring the reading of the power meter 411.

[0037] Please see Figure 3 , Figure 3 This is a flowchart illustrating a method for detecting and protecting reflected light power according to another embodiment of the present invention. In one embodiment of the present invention, step S300 includes: S310, the beam splitter 410 outputs a portion of the reflected light to the cladding light stripper 420 and another portion of the reflected light to the power meter 411; wherein, the ratio of the power of the reflected light output by the beam splitter 410 to the cladding light stripper 420 to the power of the reflected light output by the beam splitter 410 to the power meter 411 is 1:9; S320 controls the power meter 411 to detect the reflected light it receives and establishes a correspondence between the reading of the detection element 430 and the actual power of the reflected light; Step S400 includes: S410: The control detection unit 430 detects the reflected light signal stripped by the cladding light stripper 420, and based on the detection data and corresponding relationship of the detection unit 430, determines whether the actual power of the reflected light exceeds a preset threshold; if so, it controls the seed source 100 and the main amplifier 300 to be turned off. When controlling the seed source 100 and the main amplifier 300 to be turned off, the first amplifier 500 and the second amplifier 600 must be turned off simultaneously.

[0038] Specifically, the power meter 411 detects the reflected light it receives and establishes a correspondence between the reading of the detection element 430 and the actual power of the reflected light; it can provide a debugging reference for the detection element 430 to better protect the fiber laser and avoid damage.

[0039] To verify the effectiveness of the above-mentioned retroreflection power detection and protection method, during actual debugging, the main amplifier 300 is turned on. When the retroreflection power detected by the power meter 411 is higher than a certain threshold, it is determined that obvious stimulated Brillouin scattering has occurred. The detection value of the photodetector at this time is set as the upper limit protection threshold. The output power of the main amplifier 300 is further increased. The controller obtains the detection value of the photodetector and determines that the detection value exceeds the upper limit protection threshold, thereby controlling the fiber laser to shut down. In this way, the effectiveness of the above-mentioned retroreflection power detection and protection method can be verified.

[0040] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A fiber laser, characterized in that, It includes a seed source, a bandpass isolator, a main amplifier, and a detection component, wherein the seed source, the bandpass isolator, and the main amplifier are connected in sequence, and the bandpass isolator is provided with a first output port; The detection component includes a beam splitter, a cladding light stripper, and a detection component. The beam splitter is connected to the first output port, the cladding light stripper is connected to the beam splitter, and the detection component is disposed on the cladding light stripper and electrically connected to the seed source and the main amplifier. The bandpass isolator is used to isolate the reflected light and couple the reflected light to the beam splitter through the first output port. The detection device is used to detect the power of the reflected light after it has been stripped by the cladding stripper.

2. The fiber laser as described in claim 1, characterized in that, The beam splitter has a second output port and a third output port. The second output port is connected to the cladding stripper via an optical fiber. The third output port is connected to a power meter, and the power meter is electrically connected to the detection device.

3. The fiber laser as described in claim 2, characterized in that, The beam splitter is used to split the light; the beam splitter is used to output a portion of the reflected light to the cladding stripper through the second output port, and to output another portion of the reflected light to the power meter through the third output port; Definition: Let a be the power of the reflected light output from the beam splitter to the cladding stripper, and b be the power of the reflected light output from the beam splitter to the power meter; then a < b.

4. The fiber laser as described in claim 3, characterized in that, The ratio of the power of the reflected light output from the beam splitter to the cladding stripper and the power of the reflected light output from the beam splitter to the power meter should satisfy a:b = 5%:95%~15%:85%.

5. The fiber laser as described in claim 4, characterized in that, The ratio of the power of the reflected light output from the beam splitter to the cladding stripper and the power of the reflected light output from the beam splitter to the power meter is a:b = 10%:90%.

6. The fiber laser as described in claim 1, characterized in that, The fiber laser also includes a first amplifier and a second amplifier, which are connected sequentially between the seed source and the bandpass isolator.

7. The fiber laser as described in claim 6, characterized in that, The bandpass isolator is a three-port bandpass isolator, which also has an input port and a fourth output port. The input port is connected to the second amplifier, and the fourth output port is connected to the main amplifier.

8. The fiber laser as described in any one of claims 1 to 7, characterized in that, The cladding light filter is provided with a light-transmitting hole, and the detection element is disposed at the light-transmitting hole.

9. A method for detecting and protecting reflected light power, applied to a fiber laser as described in any one of claims 1 to 8, characterized in that, The method for detecting and protecting reflected light power includes: Control the seed source to emit signal light; Control the bandpass isolator to isolate the reflected light and couple the reflected light to the beam splitter; The beam splitter controls the output of the reflected light to the cladding stripper; The control detection device detects the reflected light signal stripped by the cladding light stripper, and controls the seed source and main amplifier to shut down when the actual power of the reflected light exceeds a preset threshold.

10. The method for detecting and protecting reflected light power as described in claim 9, characterized in that, The step of controlling the beam splitter to output the reflected light to the cladding stripper includes: The beam splitter is controlled to output a portion of the reflected light to the cladding light stripper and another portion of the reflected light to the power meter; wherein the ratio of the power of the reflected light output by the beam splitter to the cladding light stripper and the power of the reflected light output by the beam splitter to the power meter is 1:

9. The power meter is controlled to detect the reflected light it receives, and a correspondence is established between the reading of the detection device and the actual power of the reflected light. The step of controlling the detection device to detect the reflected light signal stripped by the cladding stripper, and controlling the seed source to shut down when the actual power of the reflected light exceeds a preset threshold, includes: The control detector detects the reflected light signal stripped by the cladding stripper, and based on the detection data of the detector and the corresponding relationship, determines whether the actual power of the reflected light exceeds a preset threshold; if so, the seed source and the main amplifier are turned off.

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