Multi-wavelength laser

Abstract

The invention discloses a multi-wavelength laser, and relates to the technical field of lasers, and the multi-wavelength laser comprises a first output device, a cladding light filter, a first light source assembly, a composite resonant cavity, a second light source assembly and a second output device which are sequentially connected through a central fiber. Wherein the composite resonant cavity is internally provided with a plurality of sub-cavities which are sequentially connected through a central fiber, and the sub-cavities are used for receiving light source light beams emitted by the first light source assembly and / or the second light source assembly and converting the light source light beams into laser beams with corresponding wavelengths; the first output device is used for receiving and emitting the laser beam generated by the composite resonant cavity, and the second output device is used for receiving and emitting the reflected light in the central fiber. According to the technical scheme, stable output of multiple wavelengths is achieved, the nonlinear effect threshold value is increased, and the higher output power level is achieved.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, in particular to a multi-wavelength laser. Background Art

[0002] As human society enters the information age, traditional communication technologies have been unable to meet the rapidly growing demand for communication capacity. Dense Wavelength Division Multiplexing (DWDM) technology can transmit multiple signals of different wavelengths on the same optical fiber, thereby greatly improving the transmission capacity.

[0003] Multi-wavelength fiber lasers have the advantages of stable performance, multi-wavelength output, low cost, fiber compatibility, and a wide tunable range. They have very important applications in fiber-optic communication systems, fiber-optic sensing, spectral analysis and other fields, and are therefore favored by scientific and technological workers and major laser manufacturers.

[0004] In the prior art, the way to achieve multi-wavelength laser emission in multi-wavelength fiber lasers is to suppress the mode competition of the gain medium by designing a special structure. This method will lead to mode competition in the laser due to the uniform broadening of the gain of erbium-doped fiber at room temperature, and it is impossible to stably establish multi-wavelength laser output, and the output power is low. Summary of the invention

[0005] The main purpose of the present invention is to provide a multi-wavelength laser, aiming to solve the technical problems of poor stability and low output power of multi-wavelength laser emission in the prior art.

[0006] To achieve the above object, the present invention provides a multi-wavelength laser, which includes a first output device, a cladding light filter, a first light source component, a composite resonant cavity, a second light source component and a second output device connected in sequence through a central fiber;

[0007] The composite resonant cavity has a plurality of sub-cavities connected in sequence through the central fiber, and the sub-cavities are used to receive the light source beam emitted by the first light source assembly and / or the second light source assembly, and convert the light source beam into a laser beam of corresponding wavelength;

[0008] The first output device is used to receive and emit the laser beam generated by the composite resonant cavity, and the second output device is used to receive and emit the reflected light in the central fiber.

[0009] In one embodiment, the sub-cavity includes two fiber Bragg gratings arranged opposite to each other and an active optical fiber arranged between the two fiber Bragg gratings, and two ends of the active optical fiber are respectively connected to the two fiber Bragg gratings through the central fiber.

[0010] In one embodiment, one of the two fiber Bragg gratings is a high-reflection grating, and the other is a low-reflection grating;

[0011] The high-reflection grating is arranged between the active optical fiber and the second output device, and the low-reflection grating is arranged between the active optical fiber and the first output device.

[0012] In one embodiment, the reflectivity of the high-reflection grating is greater than or equal to 99.5%, and the reflectivity of the low-reflection grating is less than 15%.

[0013] In one embodiment, the central wavelengths of the two corresponding fiber Bragg gratings in the sub-cavity are the same, and the central wavelengths corresponding to the plurality of sub-cavities increase in sequence along the direction from the second output device to the first output device.

[0014] In one embodiment, the active optical fiber is a rare earth ion doped optical fiber, and the rare earth ions include one or more of erbium ions, ytterbium ions, and neodymium ions.

[0015] In one embodiment, the sub-cavity is detachably connected to the central fiber.

[0016] In one embodiment, the first light source assembly comprises:

[0017] a plurality of first pump sources;

[0018] A reverse beam combiner, wherein a first beam combining end of the reverse beam combiner is connected to the composite resonant cavity, and a first branch end of the first composite resonant cavity is respectively connected to a plurality of the first pump sources and the cladding light filter.

[0019] In one embodiment, the second light source assembly comprises:

[0020] a plurality of second pump sources;

[0021] A forward beam combiner, wherein the second beam combining end of the forward beam combiner is connected to the composite resonant cavity, and the second branch ends of the forward beam combiner are respectively connected to a plurality of the second pump sources and the second output device.

[0022] In one embodiment, an end cap is provided on the output end of the first output device and / or the second output device, an anti-reflection film is provided on the end cap, and a roughened area is provided inside the first output device and / or the second output device.

[0023] The technical solution of the present invention forms a plurality of independent sub-cavities in the composite resonant cavity in the optical path structure, and the sub-cavities select the frequency of the incoming light beams, and different sub-cavities form laser beams of different wavelength bands. The laser beams of multiple wavelengths have the phenomenon of same-band pumping, which can enhance the competition of adjacent wavelengths of light for inverting the number of particles, thereby achieving stable output of multiple wavelengths. At the same time, the introduction of laser beams of multiple wavelengths effectively reduces the intensity of nonlinear effects in the optical fiber, shortens the effective action length of the nonlinear effect, increases the threshold of the nonlinear effect, and achieves a higher output power level. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of a multi-wavelength laser provided by the present invention;

[0026] Figure 2 A schematic structural diagram of a first embodiment of a composite resonant cavity in a multi-wavelength laser provided by the present invention;

[0027] Figure 3 A schematic structural diagram of a second embodiment of a composite resonant cavity in a multi-wavelength laser provided by the present invention;

[0028] Figure 4 This is a schematic structural diagram of a third embodiment of a composite resonant cavity in a multi-wavelength laser provided by the present invention.

[0029] Description of Figure Numbers:

[0030] 10. First output device; 20. Cladding light filter; 30. First light source assembly; 31. Reverse beam combiner; 32. First pump source; 40. Second light source assembly; 41. Forward beam combiner; 42. Second pump source; 50. Composite resonant cavity; 51. High-reflection grating; 52. Active optical fiber; 53. Low-reflection grating; 60. Second output device.

[0031] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] The present invention provides a multi-wavelength laser.

[0036] See also Figure 1 In one embodiment of the present invention, the multi-wavelength laser comprises a first output device 10, a cladding light filter 20, a first light source assembly 30, a composite resonant cavity 50, a second light source assembly 40 and a second output device 60 which are sequentially connected through a central fiber; wherein the composite resonant cavity 50 has a plurality of sub-cavities sequentially connected through the central fiber, the sub-cavities are used to receive the light source beam emitted by the first light source assembly 30 and / or the second light source assembly 40, and convert the light source beam into a laser beam of a corresponding wavelength; the first output device 10 is used to receive and emit the laser beam generated by the composite resonant cavity 50, and the second output device 60 is used to receive and emit the reflected light in the central fiber.

[0037] The first output device 10, the cladding light filter 20, the first light source assembly 30, the composite resonant cavity 50, the second light source assembly 40 and the second output device 60 are connected in series through the central fiber to form an optical path. Figure 1 In this embodiment, the first output device 10, the cladding light filter 20, the first light source assembly 30, the composite resonant cavity 50, the second light source assembly 40 and the second output device 60 are arranged in sequence from right to left. The laser beam is emitted from the right end of the composite resonant cavity 50, enters the left end of the first output device 10 along the central fiber, and finally emits from the right end of the first output device 10.

[0038] The first light source assembly 30 and the second light source assembly 40 inject the light source beam into the composite resonant cavity 50. The light source beam enters into a plurality of sub-cavities along the optical path respectively. The sub-cavities can convert the injected light source beam into a laser beam and emit it to the right.

[0039] In this embodiment, each sub-cavity has a unique corresponding wavelength, that is, after the light source beam enters the sub-cavity, a laser beam of the corresponding wavelength can be generated through the sub-cavity. The more sub-cavities there are, the more laser beams of different wavelengths can be generated in the composite resonant cavity 50.

[0040] For example, when the number of sub-cavities is two, the composite resonant cavity 50 can generate laser beams of two different wavelengths; when the number of sub-cavities is three, the composite resonant cavity 50 can generate laser beams of three different wavelengths, and so on.

[0041] Before the laser beam is emitted from the composite resonant cavity 50 to the first output device 10, it needs to pass through the cladding light filter 20. The cladding light filter 20 is obtained by CO2 laser etching of a passive optical fiber with a diameter of 50 / 400 / 0.12 (core diameter / cladding diameter / numerical aperture), and is used to effectively filter out the cladding light from the forward transmission or reverse transmission, and the cladding light filtering efficiency is ≥98%.

[0042] It should be noted that the laser beam is transmitted from left to right along the central fiber and finally emitted from the first output device 10. In this process, the laser beam is transmitted in the forward direction. In some cases, the laser beam may be affected by the external or internal environment, or it may be related to the characteristics of the target material. When the laser beam irradiates the target, part of the laser beam may be reflected back and transmitted from right to left along the central fiber to form back reflection light. These back reflection lights may be recoupled into the laser under certain conditions and amplified, which may cause damage to the laser system.

[0043] Therefore, in this embodiment, a second output device 60 is added at the leftmost end of the optical path of the central fiber, and the reflected back light is emitted from the left end of the second output device 60 through the second output device 60, thereby preventing the back light from entering the laser.

[0044] The technical solution of the present invention forms a plurality of independent sub-cavities in the composite resonant cavity 50 in the optical path structure, and the sub-cavities select the frequency of the incoming light beams, and different sub-cavities form laser beams of different wavelength bands. The laser beams of multiple wavelengths have the phenomenon of same-band pumping, which can enhance the competition of adjacent wavelengths of light for inverting the number of particles, thereby achieving stable output of multiple wavelengths. At the same time, the introduction of laser beams of multiple wavelengths effectively reduces the intensity of nonlinear effects in the optical fiber, shortens the effective action length of the nonlinear effect, increases the threshold of the nonlinear effect, and achieves a higher output power level.

[0045] In one embodiment of the present invention, the sub-cavity includes two oppositely arranged fiber Bragg gratings and an active optical fiber 52 arranged between the two fiber Bragg gratings. Both ends of the active optical fiber 52 are respectively connected to the two fiber Bragg gratings through the central fiber.

[0046] Multiple sub-cavities are connected in series through a central fiber. Figure 1 In a sub-cavity, a fiber grating is disposed on both the left and right sides of the active optical fiber 52 .

[0047] See also Figure 2 In this embodiment, multiple fiber gratings are arranged from left to right, namely a1, a2, a3, and a4, wherein a1 and a2 form a first sub-cavity, and the active optical fiber 52 is used to reflect the light beam emitted from the light source assembly, and the light beam frequently passes through the active optical fiber 52 between a1 and a2, thereby achieving laser enhancement. Similarly, a3 and a4 form a second sub-cavity.

[0048] The more fiber Bragg gratings there are, the more sub-cavities are formed. Figure 3 , multiple fiber Bragg gratings are arranged from left to right, in order of a1, a2, a3, a4, a5, and a6. The active optical fiber 52 is respectively arranged between a1 and a2, between a3 and a4, and between a5 and a6. Then, a first sub-cavity is formed between a1 and a2, a second sub-cavity is formed between a3 and a4, and a third sub-cavity is formed between a5 and a6.

[0049] Similarly, see Figure 4 , so as to arrange multiple fiber gratings from left to right, namely a1, a2, a3, a4, a5, a6, a7, and a8, and form sub-cavities between a1 and a2, between a3 and a4, between a5 and a6, and between a7 and a8, and so on.

[0050] Taking the leftmost sub-cavity as an example, the fiber grating on the left side of the active fiber 52 is defined as the left grating, and the fiber grating on the right side of the active fiber 52 is defined as the right grating. The left end of the left grating is connected to the right end of the second light source assembly 40, the right end of the left grating is connected to the left end of the active fiber 52, the right end of the active fiber 52 is connected to the left end of the right grating, and the right end of the right grating is connected to the left end of the left grating in the next sub-cavity, and so on, until the right end of the right grating in the rightmost sub-cavity is connected to the left end of the second light source assembly 40.

[0051] In this embodiment, the active optical fiber 52 may be a high-gain doped active optical fiber 52, that is, a rare earth ion doped optical fiber, wherein the rare earth ions include one or more of erbium ions, ytterbium ions, and neodymium ions. In addition, the active optical fiber 52 may also include Yb 3+ , Er 3+ 、Tm 3+ 、Ho 3+ or Dy 3+ At least one component is singly doped, two components are doped, or more than two components are doped in combination.

[0052] The active optical fiber 52 is used to enhance the light source beam. After the light source assembly transmits the light source beam to the sub-cavity, the wavelengths that meet the fiber Bragg condition will be reflected, and the remaining wavelengths will continue to be transmitted through the fiber Bragg grating. Therefore, the light source beam is first reflected by one of the left grating or the right grating, so that the light source beam passes through the active optical fiber 52 and then enters the other, and is reflected again and passes through the active optical fiber 52 again. After multiple reciprocations, the light source beam finally forms a laser beam and passes through the right grating and is emitted.

[0053] In this embodiment, the structural parameters of the active optical fiber 52 can be 20 / 400 / 0.065, and the absorption coefficient is about 0.38dB / m. Alternatively, 25 / 400 / 0.065 can be used, and the absorption coefficient is 0.53dB / m. The fiber grating can be obtained by hydrogen-carrying mask lithography process. In this embodiment, the central wavelength of the fiber grating can be set in the range of 1030nm to 2020nm, and the spectral bandwidth is 1 to 4nm. For example, the central wavelengths of the fiber gratings in multiple sub-cavities are set to 1050nm, 1060nm, and 1070nm, respectively, so that laser beams with wavelengths of 1050nm, 1060nm, and 1070nm are finally output from the first output device 10, respectively.

[0054] In one embodiment of the present invention, one of the two fiber gratings is a high-reflection grating 51, and the other is a low-reflection grating 53; the high-reflection grating 51 is arranged between the active optical fiber 52 and the second output device 60, and the low-reflection grating 53 is arranged between the active optical fiber 52 and the first output device 10.

[0055] In this embodiment, the low-reflection grating 53 indicates that the reflectivity of the fiber Bragg grating is low, and the high-reflection grating 51 indicates that the reflectivity of the fiber Bragg grating is high. For example, in a sub-cavity, the reflectivity of the low-reflection grating 53 can be set to be less than 15%, and the spectral bandwidth is 3nm; the reflectivity of the high-reflection grating 51 can be set to be greater than or equal to 99.5%, and the spectral bandwidth is 1nm.

[0056] See also Figure 1 , the laser beam is transmitted from left to right to the first output device 10. Therefore, the left grating in the sub-cavity is set to a low-reflection grating 53, and the right grating is set to a high-reflection grating 51. The high-reflection grating 51 is used to reflect the light beam back to the active optical fiber 52 to increase the number of times the light beam passes through the active optical fiber 52, thereby enhancing the laser beam. The reflectivity of the low-reflection grating 53 is low, so that part of the light beam can be allowed to pass through, forming a laser beam transmitted to the right.

[0057] It can be understood that the positions of the low-reflection grating 53 and the high-reflection grating 51 include but are not limited to the above-mentioned methods. When the transmission direction of the laser beam changes, they can be replaced accordingly according to the transmission direction of the laser beam.

[0058] In addition, the central wavelengths of the two corresponding fiber Bragg gratings in the sub-cavity are the same, and the central wavelengths corresponding to the plurality of sub-cavities along the direction from the second output device 60 to the first output device 10 increase in sequence.

[0059] The wavelength of the laser beam formed in each sub-cavity is different. The central wavelength of the two corresponding fiber gratings in each sub-cavity is the same. Figure 2 For example, when there are two sub-cavities, from left to right, the central wavelengths of the fiber Bragg gratings in the sub-cavities are 1070nm and 1080nm respectively; see Figure 3 For example, when there are three sub-cavities, from left to right, the central wavelengths of the fiber Bragg gratings in the sub-cavities are 1060nm, 1070nm and 1080nm respectively; see Figure 4 For example, when there are four sub-cavities, from left to right, the central wavelengths of the fiber Bragg gratings in the sub-cavities are 1060nm, 1070nm, 1080nm and 1090nm. By setting them in an increasing manner, it is ensured that the laser beam can pass through, and finally transmitted to the first output device 10 on the far right, so as to avoid the central wavelength of the fiber Bragg grating fluctuating up and down to affect the transmission of the laser beam.

[0060] In one embodiment of the present invention, the sub-cavity is detachably connected to the central fiber. Specifically, the left and right ends of the fiber grating are fused to the central fiber, and the left and right ends of the active optical fiber 52 are also fused to the central fiber.

[0061] When the number of sub-cavities needs to be increased, the central fiber between the two sub-cavities can be cut and the new sub-cavity can be welded to the central fiber between the two sub-cavities. In addition, when the number of sub-cavities needs to be reduced, the central fibers at the left and right ends of the sub-cavity can be cut, and the central fibers can be re-welded to the sub-cavities on both sides after the sub-cavity is removed. This allows for quick disassembly and assembly of sub-cavities and improves the compatibility of multi-wavelength lasers.

[0062] In one embodiment of the present invention, the first light source assembly 30 includes a reverse beam combiner 31 and a plurality of first pump sources 32, the first beam combining end of the reverse beam combiner 31 is connected to the composite resonant cavity 50, and the first branch ends of the first composite resonant cavity 50 are respectively connected to the plurality of first pump sources 32 and the cladding light filter 20.

[0063] Among them, see Figure 1 The first pump source 32 is a reverse pump source, and the second pump source 42 is a forward pump source. The two pumping modes can be used alone or in combination.

[0064] Correspondingly, the left end of the reverse beam combiner 31 is a beam combining end, and the right end is a branching end, and the left end of the forward beam combiner 41 is a branching end, and the right end is a beam combining end. The beam combiners can all be (N+1)*1 type beam combiners, such as (6+1)*1 beam combiners, and the number of first pump sources 32 is 6.

[0065] The plurality of first pump sources 32 are connected to the branch ends of the reverse beam combiner 31 through pump fibers respectively; the plurality of second pump sources 42 are connected to the branch ends of the forward beam combiner 41 through pump fibers respectively.

[0066] See also Figure 1 The beam combining end of the reverse beam combiner 31 is connected to the composite resonant cavity 50 , one of the branches at the branch end is connected to the cladding light filter 20 through the central fiber, and the other branches are connected to a first pump source 32 accordingly.

[0067] In one embodiment of the present invention, the second light source assembly 40 includes a forward combiner 41 and a plurality of second pump sources 42; the second combining end of the forward combiner 41 is connected to the composite resonant cavity 50, and the second branch end of the forward combiner 41 is respectively connected to the plurality of second pump sources 42 and the second output device 60.

[0068] Similarly, the forward beam combiner 41 is similar in structure to the reverse beam combiner 31 but in opposite directions, and a (6+1)*1 beam combiner is used. The number of the second pump sources 42 is also 6.

[0069] In one embodiment of the present invention, an end cap is provided on the output end of the first output device 10 and / or the second output device 60, an anti-reflection film is provided on the end cap, and a roughened area is provided inside the first output device 10 and / or the second output device 60.

[0070] In this embodiment, the optical fiber type of the output device is 50 / 400 / 0.12 passive optical fiber, please refer to Figure 1 The output end of the first output device 10 is the right end, and the output end of the second output device 60 is the left end, and the output end is welded to the quartz end cap coated with an anti-reflection film. There is a roughened area inside the output device obtained by corrosive abrasive corrosion or CO2 laser etching process to achieve forward cladding light stripping and reverse return cladding light stripping.

[0071] The light of the first pump source 32 and / or the second pump source 42 is generated by a semiconductor and output through optical fiber coupling. In this embodiment, the light output wavelength of the pump source is 915 nm, the output power of the pump source is ≥ 650 W, and the output pigtail is 200 / 220 / 0.22.

[0072] By modulating the injection current of the pump source, pump light with different powers can be injected into the composite resonant cavity 50, and finally the composite resonant cavity 50 is used to output a continuous 1080nm laser.

[0073] By modulating the light injected into the pump source, the laser can achieve a 1080nm fiber laser output with a high peak power of more than 2500W.

[0074] In the fiber oscillator structure, when the laser power density in the fiber is high, nonlinear effects such as stimulated Raman scattering and stimulated Brillouin scattering are easily generated, causing most of the energy to be transferred to the Stokes light, which not only affects the growth of the signal light power in the oscillator, but also the backward transmitted Stokes light will threaten the safety of the previous system. If multiple pairs of fiber gratings are used simultaneously in the oscillator to form a composite resonant cavity 50, not only the nonlinear effect intensity in the fiber is effectively reduced by introducing multiple wavelengths of light, but also the effective action length of the nonlinear effect is shortened, and the threshold of the nonlinear effect is increased, so that a higher output power level of the oscillator can be achieved.

[0075] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A multi-wavelength laser, characterized in that: The multi-wavelength laser comprises a first output device, a cladding light filter, a first light source component, a composite resonant cavity, a second light source component and a second output device which are sequentially connected through a central fiber; The composite resonant cavity has a plurality of sub-cavities connected in sequence through the central fiber, and the sub-cavities are used to receive the light source beam emitted by the first light source assembly and / or the second light source assembly, and convert the light source beam into a laser beam of corresponding wavelength; The first output device is used to receive and emit the laser beam generated by the composite resonant cavity, and the second output device is used to receive and emit the reflected light in the central fiber.

2. The multi-wavelength laser according to claim 1, characterized in that: The sub-cavity includes two fiber gratings arranged opposite to each other and an active optical fiber arranged between the two fiber gratings. Two ends of the active optical fiber are respectively connected to the two fiber gratings through the central fiber.

3. The multi-wavelength laser according to claim 2, characterized in that: One of the two fiber gratings is a high-reflection grating, and the other is a low-reflection grating; The high-reflection grating is arranged between the active optical fiber and the second output device, and the low-reflection grating is arranged between the active optical fiber and the first output device.

4. The multi-wavelength laser according to claim 3, characterized in that: The reflectivity of the high-reflection grating is greater than or equal to 99.5%, and the reflectivity of the low-reflection grating is less than 15%.

5. The multi-wavelength laser according to claim 2, characterized in that: The central wavelengths of the two corresponding fiber Bragg gratings in the sub-cavity are the same, and the central wavelengths corresponding to the plurality of sub-cavities increase in sequence along the direction from the second output device to the first output device.

6. The multi-wavelength laser according to claim 2, characterized in that: The active optical fiber is a rare earth ion doped optical fiber, and the rare earth ions include one or more of erbium ions, ytterbium ions, and neodymium ions.

7. The multi-wavelength laser according to any one of claims 1 to 6, characterized in that: The sub-cavity is detachably connected to the central fiber.

8. The multi-wavelength laser according to claim 1, characterized in that: The first light source assembly comprises: a plurality of first pump sources; A reverse beam combiner, wherein a first beam combining end of the reverse beam combiner is connected to the composite resonant cavity, and a first branch end of the first composite resonant cavity is respectively connected to a plurality of the first pump sources and the cladding light filter.

9. The multi-wavelength laser according to claim 1, characterized in that: The second light source assembly comprises: a plurality of second pump sources; A forward beam combiner, wherein the second beam combining end of the forward beam combiner is connected to the composite resonant cavity, and the second branch ends of the forward beam combiner are respectively connected to a plurality of the second pump sources and the second output device.

10. The multi-wavelength laser according to claim 1, characterized in that: An end cap is provided on the output end of the first output device and / or the second output device, an anti-reflection film is provided on the end cap, and a roughened area is provided inside the first output device and / or the second output device.

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