Cladding light recycling device and laser

Abstract

The application discloses a cladding light recycling device and a laser, and relates to the technical field of lasers. The photoluminescence conversion layer can convert the cladding light into conversion light which is controlled in wavelength, omni-directionally radiates and is easy to be transmitted in a waveguide, and the conversion light is transmitted to a photovoltaic unit of an end surface of a multi-layer waveguide structure through a fluid waveguide core layer and a light confinement layer to realize concentrated photoelectric conversion. Meanwhile, the high convection heat exchange coefficient of the fluid medium is used to remove Stokes heat generated in the light conversion process in real time, so that efficient cold stripping of residual cladding light and low-cost energy recycling are realized.

Description

Technical Field

[0001] This application relates to the field of laser technology, and in particular to a cladding light recovery device and a laser. Background Technology

[0002] With the widespread adoption of high-power double-clad fiber laser technology in industrial manufacturing and defense, its output power has successfully broken through the 20kW mark and is moving towards even higher levels. However, accompanying this power increase is a sharp increase in the residual cladding light energy transmitted in the inner cladding. This energy, mainly composed of 976 / 915nm pump light that is not completely absorbed by the gain fiber and 1064 / 1080nm signal light generated by effects such as leakage from bent fibers, fiber splice excitation, or mode instability, is no longer negligible waste light but has become an important factor affecting the survivability of the system.

[0003] In current industrial practices, the cladding light power to be stripped often reaches the kilowatt level. Faced with such a huge energy dissipation requirement, the traditional dissipative technologies currently relied upon by the industry are facing severe challenges from multiple dimensions. The most prominent issue is the energy efficiency bottleneck and the dual energy consumption problem. Currently, the optical-to-optical conversion efficiency of fiber lasers is usually around 70% to 80%, which means that 10% to 20% of the total input energy of the cladding light is wasted. This is particularly fatal in off-grid loads or portable platforms that rely on battery power, directly compressing the equipment's battery life and operating radius. Moreover, the existing processing mode wastes the electrical energy used to generate this portion of the laser. Summary of the Invention

[0004] The purpose of this application is to provide a cladding light recovery device and a laser that can convert cladding light into wavelength-controlled, omnidirectionally radiating, and easily waveguide-transmitted converted light. The light energy is then transmitted to the end face of a multilayer waveguide structure for concentrated photoelectric conversion using fluid waveguide technology. At the same time, the high convective heat transfer coefficient of the fluid medium is used to remove the Stokes heat generated during the light conversion process in real time, thereby achieving "cold stripping" and "high-grade recovery" of light energy.

[0005] To achieve the above objectives, this application provides the following solution:

[0006] In a first aspect, this application provides a cladding light recovery device, comprising:

[0007] A coaxial nested multilayer waveguide structure, wherein the multilayer waveguide structure comprises, from the inside out: a photoluminescence conversion layer, a fluid waveguide core layer, and an optical confinement layer;

[0008] The photoluminescence conversion layer is disposed on the periphery of the target object and is used to absorb the cladding light leaked from the target object and convert it into converted light;

[0009] The fluid waveguide core layer is disposed around the photoluminescence conversion layer. The fluid waveguide core layer includes an optical coolant with a refractive index matching, which is used to receive and transmit the converted light along the axial direction in the form of internal reflection, and at the same time remove the heat generated during the light conversion process through convection heat transfer.

[0010] The optical confinement layer is disposed on the periphery of the fluid waveguide core layer and is used to reflect the converted light into the fluid waveguide core layer.

[0011] At least one end face of the multilayer waveguide structure is provided with a photovoltaic unit, which is used to receive the converted light transmitted along the axial direction and convert it into electrical energy.

[0012] Optionally, the photoluminescence conversion layer is formed in the following manner:

[0013] Photoluminescent material is coated onto the outer wall of the target object.

[0014] Optionally, the photoluminescent conversion layer is formed by directly doping a photoluminescent material into an independent sleeve, which is then fitted around the target object.

[0015] Optionally, the photoluminescence conversion layer includes ytterbium ions and erbium ions, used to convert cladding light of 976 nm and / or 1064 nm into converted light through an upconversion nonlinear effect; the photovoltaic unit is a silicon photovoltaic cell.

[0016] Optionally, the photoluminescent conversion layer comprises colloidal quantum dots, including lead sulfide quantum dots or lead selenide quantum dots, for converting cladding light in the range of 915 nm to 1080 nm into converted light in the range of 1100 nm to 1300 nm through a downconversion effect; the photovoltaic unit is an indium gallium arsenide photovoltaic cell.

[0017] Optionally, the refractive index of the optical coolant matches the refractive index of the photoluminescence conversion layer, with a refractive index difference of less than 0.05; the optical coolant includes modified phenyl silicone oil, fluorinated liquid, or perfluoropolyether.

[0018] Optionally, the light confinement layer is a quartz tube coated with a distributed Bragg mirror or a highly reflective metal film.

[0019] Optionally, the cladding light recovery device further includes a multiplexing module, the multiplexing module comprising:

[0020] A current sampling module is used to collect the photocurrent generated by the photovoltaic unit in real time;

[0021] The power load module is powered by the photovoltaic unit;

[0022] The main control module is electrically connected to the current sampling module and the power load module. The main control module uses the photocurrent collected by the current sampling module as a monitoring signal characterizing the cladding optical power, and is configured to send an activation command to the power load module and send an alarm message to the outside world when the monitoring signal is abnormal.

[0023] Optionally, the end face of the multilayer waveguide structure is a tapered end face that tapers towards the photovoltaic unit.

[0024] Secondly, this application provides a laser comprising:

[0025] optical fiber;

[0026] As described in any embodiment of the first aspect, the cladding light recovery device is coaxially nested around the periphery of the optical fiber.

[0027] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0028] This application provides a cladding light recovery device and a laser. The photoluminescence conversion layer can convert cladding light into wavelength-controlled, omnidirectionally radiating, and easily waveguide-transmitted converted light. The converted light is then transmitted to the photovoltaic unit at the end face of the multilayer waveguide structure through the fluid waveguide core layer and the optical confinement layer for centralized photoelectric conversion. At the same time, the high convective heat transfer coefficient of the fluid medium is used to remove the Stokes heat generated during the light conversion process in real time, thereby achieving efficient cold stripping of residual cladding light and low-cost energy recovery. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the multilayer waveguide structure and the target object in one embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the optical path of the converted light under the fluid waveguide core and optical confinement layer according to an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of the cladding light recovery device;

[0033] Figure 4 This is a schematic diagram of the optical path of cladding light in a cladding light recovery device according to an embodiment of this application;

[0034] Figure 5 This is a schematic diagram of an upconversion process provided in an embodiment of this application;

[0035] Figure 6 This is a schematic diagram of a downconversion process provided in an embodiment of this application;

[0036] Figure 7 This is a schematic diagram of the stacked structure of a multilayer waveguide structure with an octagonal cross-section, provided in one embodiment of this application.

[0037] Figure reference numerals: 1. Optical fiber; 2. Inner cladding; 3. Photoluminescence conversion layer; 31. Sleeve; 4. Fluid waveguide core layer; 41. Liquid inlet; 42. Liquid outlet; 5. Optical confinement layer; 6. Photovoltaic unit; 10. Multilayer waveguide structure; 60. Multiplexing module; 61. Current sampling module; 62. Electrical load module; 63. Main control module. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] To achieve the above objectives, this application provides the following solution:

[0041] Please see Figure 1 In a first aspect, this application provides a cladding light recovery device, comprising:

[0042] A coaxially nested multilayer waveguide structure 10 comprises, from the inside out: a photoluminescence conversion layer 3, a fluid waveguide core layer 4, and an optical confinement layer 5. The photoluminescence conversion layer 3 is disposed around the target object and absorbs cladding light leaking from the target object, converting it into converted light. The fluid waveguide core layer 4 is disposed around the photoluminescence conversion layer 3 and includes a refractive index-matched optical coolant. It receives and transmits the converted light axially via internal reflection, while simultaneously removing heat generated during the light conversion process through convection. The optical confinement layer 5 is disposed around the fluid waveguide core layer 4 and reflects the converted light into the fluid waveguide core layer 4. At least one end face of the multilayer waveguide structure 10 is provided with a photovoltaic unit 6, which receives the axially transmitted converted light and converts it into electrical energy.

[0043] It should be noted that the target object can be an optical fiber 1 with a micro-processed surface. A quartz glass tube can be nested outside the optical fiber 1 to support the fragile internal optical fiber 1.

[0044] Please refer to the following: Figure 2 , Figure 3 and Figure 4 This application provides a cladding light recovery device. The photoluminescence conversion layer 3 converts cladding light into wavelength-controlled, omnidirectionally radiating, and easily waveguide-transmitted light. The converted light is then transmitted to the photovoltaic unit 6 at the end face of the multilayer waveguide structure 10 via the fluid waveguide core layer 4 and the light confinement layer 5 for concentrated photoelectric conversion. Simultaneously, the high convective heat transfer coefficient of the fluid medium is used to remove Stokes heat generated during the light conversion process in real time, achieving efficient cold stripping of residual cladding light and low-cost energy recovery. This solution transforms a "point heat source" into a "volume light source," thus avoiding the formation of local hot spots.

[0045] Optionally, the photoluminescence conversion layer 3 is formed in the following manner:

[0046] Photoluminescent materials are coated onto the outer wall of the target object.

[0047] When the target object is protected by an outer tube wall as a rigid support, the photoluminescent material can be directly coated onto the outer tube wall. This embodiment solves the core problem of how to effectively allow the converted light to enter the waveguide. When the photoluminescent material is coated on the outer tube wall, the converted light, with the portion facing outward (radially outward), directly enters the refractive index-matched fluid waveguide core layer 4. Since the fluid core layer is the light transmission channel, this method achieves "instantaneous emission and guidance," resulting in extremely high coupling efficiency. Furthermore, a core challenge in high-power laser applications is heat dissipation. The outer tube wall coating scheme has inherent advantages in thermal management. The luminescent material generates Stokes heat during light conversion. When the material is located on the outer tube wall, the heat it generates is directly and instantly transferred to the flowing optical coolant in contact with it. The convective energy of the optical coolant is used to carry away the heat with extremely high efficiency, improving heat dissipation efficiency.

[0048] Optionally, the photoluminescent conversion layer 3 is formed by directly doping a photoluminescent material into an independent sleeve, which is then placed around the target object.

[0049] In this embodiment, when the cladding light passes through the inner glass tube, it illuminates the entire thickness cross-section of the quartz tube sleeve. The light-emitting centers doped throughout the entire volume of the sleeve can be excited, generating a spatially uniform columnar light source. This solves the problem of localized "hot spots" or uneven excitation that may occur in traditional solutions, resulting in a more uniform and stable light field of the converted light ultimately entering the fluid waveguide.

[0050] Optionally, the refractive index of the optical coolant is matched with the refractive index of the sleeve constituting the photoluminescence conversion layer 3, and the refractive index difference is less than 0.05; the optical coolant includes modified phenyl silicone oil, fluorinated liquid or perfluoropolyether.

[0051] The refractive index of the optical coolant is between 1.4 and 1.5, including 1.4, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49, and 1.50. The refractive index of the fluid waveguide core layer 4 is mainly determined by the refractive index of the optical coolant. As the main generation layer of the waveguide, the fluid waveguide core layer 4 has a large numerical aperture (NA) that can capture most of the re-emitted photons.

[0052] Please see Figure 5 Optionally, the photoluminescent conversion layer 3 includes ytterbium ions and erbium ions, used to convert cladding light of 976 nm and / or 1064 nm into converted light through upconversion nonlinear effects; the photovoltaic unit 6 is a silicon photovoltaic cell.

[0053] In this embodiment, the converted light is visible light. Addressing the complex operating condition of a double-clad fiber laser where 976 nm pump light and 1064 nm signal light coexist, this embodiment employs a broad-spectrum-response rare-earth-doped fluoride nanocrystal (such as a β-NaYF4 matrix) as the core light conversion medium, utilizing ytterbium ions (Yb). 3+ ) and erbium ions (Er 3+ The co-doping strategy of ytterbium ions (Yb) is used to achieve dual-wavelength capture and upconversion. Specifically, for the 976 nm residual pump light, the sensitizer ytterbium ions (Yb) are mainly relied upon. 3+ This wavelength exhibits resonant absorption across a large absorption cross-section, transferring energy non-radiatively to the activator erbium ions (Er) via a highly efficient energy transfer upconversion (ETU) mechanism. 3+ This causes the ytterbium ion to transition to an excited state and emit visible light. As for the 1064 nm leakage signal light, although it is located at the long-wavelength tail of the ytterbium ion's absorption, thanks to the extremely high photon flux density in the stripping section, photons in this band can directly trigger erbium ions (Er...). 3+ The photovoltaic unit 6 overcomes the limitation of low linear absorption coefficient by achieving multiphoton absorption through a cascaded process of ground-state and excited-state absorption, or through a phonon-assisted non-resonant energy transfer mechanism. This induces a significant photon avalanche effect under strong laser irradiation, ultimately converting two infrared light bands into 520-550 nm green light or 650-670 nm red light emission, which are easily absorbed by silicon solar cells. In this case, photovoltaic unit 6 is a silicon photovoltaic cell sensitive to visible light, and its cost is low.

[0054] According to nonlinear optics theory, the upconversion luminescence intensity and excitation power density exhibit a significant nonlinear power-law relationship; that is, for a typical ytterbium-erbium co-doped two-photon process, the luminescence intensity is approximately proportional to the square of the excitation power. In the stripping section of a kilowatt-level fiber laser, the power density of the inner cladding 2 optical field is typically as high as 10³–10⁴ W / cm², a value 5–6 orders of magnitude higher than the standard solar constant. Driven by such a supersaturated, strong excitation field, the metastable energy level lifetime of rare-earth ions is fully utilized, and the probability of excited-state absorption increases exponentially. The emitted 540 nm green light or 650 nm red light happens to be located in the peak region of the spectral response curve of a monocrystalline silicon photovoltaic cell. Silicon cells have high external quantum efficiency in this wavelength band and are inexpensive.

[0055] Please see Figure 6 Optionally, the photoluminescent conversion layer 3 contains colloidal quantum dots, including lead sulfide quantum dots or lead selenide quantum dots, for converting cladding light in the range of 915 nm to 1080 nm into converted light in the range of 1100 nm to 1300 nm through the downconversion effect; the photovoltaic unit 6 is an indium gallium arsenide photovoltaic cell.

[0056] In this embodiment, the converted light is fluorescence, applied to applications with extremely high energy conversion efficiency. This embodiment constructs a downconversion recovery mechanism based on colloidal quantum dots. The core of this mechanism lies in utilizing the Stokes shift characteristics of infrared quantum dots such as lead sulfide (PbS) or lead selenide (PbSe) to redshift and shape the spectral color of the cladding light. The downconversion process is a linear photoluminescence phenomenon with high quantum yield. The quantum dot coating of the photoluminescence conversion layer 3 can absorb residual pump light and leakage signal light in the 915 nm to 1080 nm range across a broad spectrum. After absorption, photons undergo an extremely short lattice relaxation process, and then radiate fluorescence with a wavelength in the 1100 nm to 1300 nm range with near-single-type quantum efficiency. This emission band is precisely tuned and designed to fall precisely into the quantum efficiency peak region where indium gallium arsenide photovoltaic cells have the highest spectral responsivity. More importantly, by utilizing the total internal reflection light confinement mechanism of the fluid waveguide, the originally divergent large-area light is focused and output to the end face of the multi-layer waveguide structure 10. This high geometric gain characteristic allows for energy recovery by configuring a small area of ​​high-performance indium gallium arsenide photovoltaic cells on the end face. This ensures high photoelectric conversion efficiency while greatly avoiding the cost barrier of expensive infrared cells under large-area deployment, achieving a dual optimization of energy efficiency and economy.

[0057] The core advantage of this embodiment lies in overcoming the limitations of traditional geometric optics in terms of expansion through a waveguide mechanism. Under an ideal waveguide model, the overall optical efficiency of the system is primarily determined by the product of quantum yield, Stokes displacement efficiency, and waveguide trapping efficiency. Assuming an excitation wavelength of 976 nm and an emission wavelength of 1200 nm, the inherent Stokes energy loss is approximately 19%, meaning that about 81% of the photon energy is retained in the optical field. Thanks to the total internal reflection cavity structure formed by the optical confinement layer 5 and the fluid waveguide core layer 4, the photon escape cone angle is compressed to its limit. Combined with the current quantum yield of over 90% for high-quality colloidal quantum dots, the photon transport efficiency inside the waveguide can conservatively be calculated to be over 70%.

[0058] Please see Figure 7 Optionally, the cross-section of the multilayer waveguide structure 10 is polygonal, including hexagonal or octagonal polygonal structures, to optimize spatial stacking density or facilitate planar coating processes during array integration. Furthermore, when stacked in this manner, spatial gaps can be left to facilitate heat dissipation during integrated stacking.

[0059] Optionally, the light confinement layer 5 is a quartz tube coated with distributed Bragg mirrors or a highly reflective metal film.

[0060] In this example, approximately 75% of the converted photons propagate in the fluid waveguide core layer 4 at an angle greater than the critical angle (θc), and this portion of the light is transported via total internal reflection. For the escape cone with an angle less than the critical angle, the optical confinement layer 5 forces it back into the fluid waveguide core layer 4, thereby achieving a photon capture rate close to the theoretical limit. This solves the geometric optics problem of collecting chaotic lateral scattered light from fiber 1.

[0061] Optionally, the fluid waveguide core layer 4 is also provided with a liquid inlet 41 and a liquid outlet 42, which are used to connect to an external circulation system to improve the cooling effect of the optical coolant.

[0062] Please see Figure 3 Optionally, the cladding light recovery device further includes a multiplexing module 60, which includes:

[0063] The current sampling module 61 is used to collect the photocurrent generated by the photovoltaic unit 6 in real time;

[0064] The electrical load module 62 is powered by the photovoltaic unit 6;

[0065] The main control module 63 is electrically connected to the current sampling module 61 and the power load module 62. The main control module 63 uses the photocurrent collected by the current sampling module 61 as a monitoring signal characterizing the cladding optical power, and is configured to send an activation command to the power load module 62 and send alarm information to the outside when the monitoring signal is abnormal.

[0066] In this embodiment, the output photocurrent is configured as the energy source to drive the heat dissipation load, and simultaneously serves as a monitoring signal characterizing the linear change in cladding optical power, enabling the digital multiplexing of passive devices. This achieves a three-in-one "stripping + recycling + monitoring" process while improving monitoring accuracy. The load module can be a microfluidic pump or a piezoelectric fan. This embodiment integrates a high-precision current sampling module 61 into the photovoltaic output circuit, enabling self-powered thermal management while delivering electrical energy to the power-consuming load module 62 (such as a microfluidic pump or piezoelectric fan), and simultaneously extracting an analog electrical signal proportional to the cladding optical power in real time. This signal is fed back to the laser's main control module 63 to establish a millisecond-level closed-loop control strategy: when an abnormal step or continuous drift in the photocurrent is detected, the main control module 63 determines it as degradation of the front-end fusion joint or high-reflectivity intrusion, and executes a power reduction or emergency shutdown command. Compared to traditional optoelectronic PD designs, this low-noise, high-linearity approach significantly improves accuracy and reduces the false alarm rate. This design endows the passive stripper with digital sensing capabilities without adding any optical insertion elements, enabling lifecycle monitoring of the health status of the optical path.

[0067] Optionally, the end face of the multilayer waveguide structure 10 is a tapered end face that tapers towards the photovoltaic unit 6.

[0068] By setting the end face as a tapered end face that tapers towards the photovoltaic unit 6, the lateral leakage light from a large area can be concentrated to the output of a very small end face, thereby significantly increasing the light power density of the end face and matching smaller photovoltaic cells.

[0069] Secondly, this application provides a laser comprising:

[0070] Fiber 1;

[0071] As in any embodiment of the first aspect, the cladding light recovery device is coaxially nested around the periphery of the optical fiber 1.

[0072] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0073] This application provides a laser in which the photoluminescence conversion layer 3 can convert the cladding light generated by the optical fiber 1 into wavelength-controlled, omnidirectionally radiating, and easily waveguide-transmitted converted light. The converted light is then transmitted to the photovoltaic unit 6 at the end face of the multilayer waveguide structure 10 through the fluid waveguide core layer 4 and the optical confinement layer 5 for concentrated photoelectric conversion. At the same time, the high convective heat transfer coefficient of the fluid medium is used to remove the Stokes heat generated during the light conversion process in real time, thereby achieving efficient cold stripping of residual cladding light and low-cost energy recovery.

[0074] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A cladding light recovery device, characterized in that, The cladding light recovery device includes: A coaxial nested multi-layer waveguide structure, wherein the multi-layer waveguide structure comprises, from the inside out: a photoluminescence conversion layer, a fluid waveguide core layer, and an optical confinement layer; The photoluminescence conversion layer is disposed on the periphery of the target object and is used to absorb the cladding light leaked from the target object and convert it into converted light; The fluid waveguide core layer is disposed around the photoluminescence conversion layer. The fluid waveguide core layer includes an optical coolant with a refractive index matching, which is used to receive and transmit the converted light along the axial direction in the form of internal reflection, and at the same time remove the heat generated during the light conversion process through convection heat transfer. The optical confinement layer is disposed on the periphery of the fluid waveguide core layer and is used to reflect the converted light into the fluid waveguide core layer. At least one end face of the multilayer waveguide structure is provided with a photovoltaic unit, which is used to receive the converted light transmitted along the axial direction and convert it into electrical energy.

2. The cladding light recovery device according to claim 1, characterized in that, The photoluminescence conversion layer is formed in the following manner: Photoluminescent material is coated onto the outer wall of the target object.

3. The cladding light recovery device according to claim 1, characterized in that, The photoluminescent conversion layer is formed by directly doping a photoluminescent material into an independent sleeve, which is then fitted around the target object.

4. The cladding light recovery device according to claim 1, characterized in that, The photoluminescent conversion layer includes ytterbium ions and erbium ions, which are used to convert cladding light of 976 nm and / or 1064 nm into converted light through upconversion nonlinear effects; the photovoltaic unit is a silicon photovoltaic cell.

5. The cladding light recovery device according to claim 1, characterized in that, The photoluminescent conversion layer contains colloidal quantum dots, including lead sulfide quantum dots or lead selenide quantum dots, which are used to convert cladding light in the range of 915 nm to 1080 nm into converted light in the range of 1100 nm to 1300 nm through downconversion effect; the photovoltaic unit is an indium gallium arsenide photovoltaic cell.

6. The cladding light recovery device according to claim 3, characterized in that, The refractive index of the optical coolant matches the refractive index of the sleeve constituting the photoluminescence conversion layer, and the refractive index difference is less than 0.05; the optical coolant includes modified phenyl silicone oil, fluorinated liquid or perfluoropolyether.

7. The cladding light recovery device according to claim 1, characterized in that, The light confinement layer is a quartz tube coated with a distributed Bragg mirror or a highly reflective metal film.

8. The cladding light recovery device according to claim 1, characterized in that, The cladding light recovery device further includes a multiplexing module, which includes: A current sampling module is used to collect the photocurrent generated by the photovoltaic unit in real time; The power load module is powered by the photovoltaic unit; The main control module is electrically connected to the current sampling module and the power load module. The main control module uses the photocurrent collected by the current sampling module as a monitoring signal characterizing the cladding optical power, and is configured to send an activation command to the power load module and send an alarm message to the outside world when the monitoring signal is abnormal.

9. The cladding light recovery device according to claim 1, characterized in that, The end face of the multilayer waveguide structure is a tapered end face that tapers towards the photovoltaic unit.

10. A laser, characterized in that, include: optical fiber; The cladding light recovery device as described in any one of claims 1-9, wherein the cladding light recovery device is coaxially nested around the periphery of the optical fiber.

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