Multiple wavelength laser

Abstract

The application discloses a kind of multi-wavelength lasers, it is related to laser technical field, multi-wavelength laser includes the first output device, cladding light filter, first light source component, composite resonant cavity, second light source component and second output device by center fiber sequentially connected;Wherein, composite resonant cavity has multiple sub-cavities by center fiber sequentially connected, and sub-cavities are used to receive the light source beam emitted by first light source component and / or second light source component, and light source beam is converted into corresponding wavelength laser beam;First output device is used to receive and emit the laser beam generated by composite resonant cavity, and second output device is used to receive and emit the back reflection in center fiber.The technical scheme of the application realizes the stable output of multi-wavelength, improves nonlinear effect threshold, and realizes higher output power level.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a multi-wavelength laser. Background Technology

[0002] As human society enters the information age, traditional communication technologies can hardly 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 significantly improving transmission capacity.

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

[0004] In existing technologies, multi-wavelength fiber lasers achieve multi-wavelength laser emission by designing a special structure to suppress mode competition in the gain medium. However, because erbium-doped fiber gain exhibits uniform broadening at room temperature, this method leads to mode competition within the laser, resulting in unstable multi-wavelength laser output and relatively low output power. Summary of the Invention

[0005] The main objective of this invention is to propose a multi-wavelength laser, which aims to solve the technical problems of poor stability and low output power in the existing multi-wavelength laser emission methods.

[0006] To achieve the above objectives, the present invention proposes a multi-wavelength laser, which includes a first output device, a cladding optical filter, a first light source assembly, a composite resonant cavity, a second light source assembly, and a second output device connected sequentially via a central fiber.

[0007] The composite resonant cavity has multiple sub-cavities connected sequentially by the central fiber. The sub-cavities are used to receive light beams emitted by the first light source assembly and / or the second light source assembly, and convert the light beams into laser beams of corresponding wavelengths.

[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 subcavity includes two opposing fiber Bragg gratings and an active optical fiber disposed between the two fiber Bragg gratings, with both ends of the active optical fiber connected to the two fiber Bragg gratings respectively via the central fiber.

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

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

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

[0013] In one embodiment, the center wavelengths of the two corresponding fiber gratings in the sub-cavities are the same, and the center wavelengths of the multiple sub-cavities increase sequentially 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, wherein 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 includes:

[0017] Multiple primary pump sources;

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

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

[0020] Multiple secondary pump sources;

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

[0022] In one embodiment, the output terminals of the first output device and / or the second output device are provided with end caps, the end caps are provided with antireflection films, and the interiors of the first output device and / or the second output device have texturized regions.

[0023] The technical solution of this invention forms multiple independent sub-cavities within the composite resonant cavity in the optical path structure. These sub-cavities selectively select the frequency of the incoming light beam, with different sub-cavities corresponding to different wavelength bands of laser beams. The co-pumping phenomenon of multiple wavelength laser beams enhances the competition for the inverted particle number between adjacent wavelengths, thereby achieving stable multi-wavelength output. Simultaneously, the introduction of multiple wavelength laser beams effectively reduces the intensity of nonlinear interactions within the optical fiber, shortens the effective length of the nonlinear effect, increases the nonlinear effect threshold, and achieves higher output power levels. Attached Figure Description

[0024] 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.

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

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

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

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

[0029] Explanation of icon numbers:

[0030] 10. First output device; 20. Cladding optical 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 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

[0032] 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.

[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 positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0034] Furthermore, if the embodiments of this 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. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text 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. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0035] This invention proposes a multi-wavelength laser.

[0036] Please see Figure 1 In one embodiment of the present invention, the multi-wavelength laser includes a first output device 10, a cladding optical 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 via a central fiber. The composite resonant cavity 50 has multiple sub-cavities sequentially connected via the central fiber. These sub-cavities are used to receive light beams emitted by the first light source assembly 30 and / or the second light source assembly 40, and to convert the light beams into laser beams of corresponding wavelengths. 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 reflected light from the central fiber.

[0037] The first output device 10, cladding optical filter 20, first light source assembly 30, composite resonant cavity 50, second light source assembly 40, and second output device 60 are connected in series via a central fiber to form an optical path. Please refer to [link / reference]. Figure 1 In this embodiment, the first output device 10, the cladding optical 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 sequentially 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 exits from the right end of the first output device 10.

[0038] The first light source assembly 30 and the second light source assembly 40 direct the light beam into the composite resonant cavity 50. The light beam then enters multiple sub-cavities along the optical path. Each sub-cavity can convert the incoming light beam into a laser beam and project 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. Therefore, 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 there are two sub-cavities, the composite resonant cavity 50 can generate two different wavelengths of laser beams; when there are three sub-cavities, the composite resonant cavity 50 generates three different wavelengths of laser beams, and so on.

[0041] Before the laser beam enters the first output unit 10 through the composite resonant cavity 50, 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 core diameter of 50 / 400 / 0.12 (core diameter / cladding diameter / numerical aperture), and is used to efficiently filter out cladding light from forward or reverse propagation, with a cladding light filtering efficiency of ≥98%.

[0042] It should be noted that the laser beam travels along the central fiber from left to right and is finally emitted from the first output unit 10; during this process, the laser beam travels in the forward direction. In some cases, due to external or internal environmental influences, or related to the properties of the target material, when the laser beam illuminates the target, part of the laser beam may be reflected back, traveling along the central fiber from right to left, forming retroreflected light. Under certain conditions, this retroreflected light may be recoupled into the laser and amplified, potentially causing 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. The reflected light is emitted from the left end of the second output device 60, thereby preventing the reflected light from entering the laser.

[0044] The technical solution of this invention forms multiple independent sub-cavities in the composite resonant cavity 50 within the optical path structure. These sub-cavities selectively select the frequency of the incoming light beam, with different sub-cavities corresponding to different wavelength bands of laser beams. The co-pumping phenomenon of multiple wavelength laser beams enhances the competition for the inverted particle number between adjacent wavelengths, thereby achieving stable multi-wavelength output. Simultaneously, the introduction of multiple wavelength laser beams effectively reduces the intensity of nonlinear effects within the optical fiber, shortens the effective length of the nonlinear effect, increases the nonlinear effect threshold, and achieves higher output power levels.

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

[0046] Multiple sub-cavities are connected in series via a central fiber. Please refer to [link / reference]. Figure 1 Within a sub-cavity, a fiber grating is disposed on both the left and right sides of the active optical fiber 52.

[0047] Please see Figure 2 In this embodiment, multiple fiber gratings are arranged from left to right as a1, a2, a3, and a4. a1 and a2 form the first sub-cavity, where the active fiber 52 reflects the light beam emitted from the light source assembly. The light beam frequently passes through the active fiber 52 between a1 and a2, thereby enhancing the laser beam. Similarly, a3 and a4 form the second sub-cavity.

[0048] The more fiber gratings used, the more subcavities are formed. (See also:) Figure 3 Multiple fiber gratings are arranged from left to right as a1, a2, a3, a4, a5, and a6. Active fibers 52 are respectively placed between a1 and a2, between a3 and a4, and between a5 and a6. The first sub-cavity is formed between a1 and a2, the second sub-cavity is formed between a3 and a4, and the third sub-cavity is formed between a5 and a6.

[0049] Similarly, please refer to Figure 4 Multiple fiber gratings are arranged from left to right as a1, a2, a3, a4, a5, a6, a7, and a8, respectively forming 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 can 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. Furthermore, the active optical fiber 52 may also include Yb. 3+ Er 3+ Tm 3+ Ho 3+ or Dy 3+ At least one component may be used for single doping, two components may be used for double doping, or more than two components may be used in combination.

[0052] Active fiber 52 is used to enhance the light source beam. After the light source assembly transmits the light source beam into the sub-cavity, wavelengths that satisfy the Bragg condition of the fiber grating will be reflected, while the remaining wavelengths continue to propagate through the fiber grating. Therefore, the light source beam is first reflected by either the left or right grating, and then, after passing through the active fiber 52, it enters the other grating, is reflected again, and passes through the active fiber 52 again. After repeating this process multiple times, the light source beam finally forms a laser beam that passes through the right grating and exits.

[0053] In this embodiment, the structural parameters of the active optical fiber 52 can be 20 / 400 / 0.065, with an absorption coefficient of approximately 0.38 dB / m, or 25 / 400 / 0.065, with an absorption coefficient of 0.53 dB / m. The fiber grating can be obtained using a hydrogen-loaded mask photolithography process. In this embodiment, the center wavelength of the fiber grating can be set in the range of 1030 nm to 2020 nm, with a spectral bandwidth of 1 to 4 nm. For example, the center wavelengths of the fiber gratings in multiple sub-cavities can be set to 1050 nm, 1060 nm, and 1070 nm, respectively, so that laser beams with wavelengths of 1050 nm, 1060 nm, and 1070 nm are ultimately output from the first output device 10.

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

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

[0056] Please see 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 as a low-reflection grating 53, and the right grating is set as a high-reflection grating 51. The high-reflection grating 51 is used to reflect the beam back into the active fiber 52 to increase the number of times the beam passes through the active fiber 52, thereby enhancing the laser beam. The low-reflection grating 53 has a lower reflectivity, thus allowing part of the beam to pass through, resulting in the laser beam being transmitted to the right.

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

[0058] Furthermore, the center wavelengths of the two corresponding fiber gratings in the sub-cavities are the same, and the center wavelengths of the multiple sub-cavities increase sequentially along the direction from the second output device 60 to the first output device 10.

[0059] The laser beam formed in each sub-cavity has a different wavelength. The center wavelengths of the two corresponding fiber gratings in each sub-cavity are the same. (See also...) Figure 2 For example, when two sub-cavities are set, from left to right, the center wavelengths of the fiber gratings in the sub-cavities are 1070nm and 1080nm respectively; please refer to [link / reference]. Figure 3 For example, when three sub-cavities are set, from left to right, the center wavelengths of the fiber gratings in the sub-cavities are 1060nm, 1070nm, and 1080nm respectively; please refer to [link / reference]. Figure 4 For example, when four sub-cavities are set, from left to right, the center wavelengths of the fiber gratings in the sub-cavities are 1060nm, 1070nm, 1080nm, and 1090nm respectively. By setting them in an incremental manner, it is ensured that the laser beam can pass through and finally be transmitted to the first output device 10 on the far right, avoiding the fluctuation of the center wavelength of the fiber grating from affecting 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, both ends of the fiber grating are fused to the central fiber, and both ends of the active fiber 52 are also fused to the central fiber.

[0061] When the number of subcavities needs to be increased, the central fiber between two subcavities can be cut, and the new subcavity can be fused to the central fiber between the two subcavities. Conversely, when the number of subcavities needs to be reduced, the central fibers at both ends of the subcavity can be cut, the subcavity removed, and the central fibers re-fused to the subcavities on both sides. This allows for rapid assembly and disassembly of subcavities, improving 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 end of the first composite resonant cavity 50 is connected to the plurality of first pump sources 32 and the cladding light filter 20, respectively.

[0063] Please refer to 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 methods can be used individually or in combination.

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

[0065] Multiple first pump sources 32 are respectively connected to the branch ends of the reverse combiner 31 via pump fibers; multiple second pump sources 42 are respectively connected to the branch ends of the forward combiner 41 via pump fibers.

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

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

[0068] Similarly, the forward combiner 41 and the reverse combiner 31 have similar structures but opposite directions. They are (6+1)*1 combiners, and the number of second pump sources 42 is also 6.

[0069] In one embodiment of the present invention, the output end of the first output device 10 and / or the second output device 60 is provided with an end cap, the end cap is provided with an anti-reflection film, and the interior of the first output device 10 and / or the second output device 60 has a texturing region.

[0070] In this embodiment, the output device uses 50 / 400 / 0.12 passive fiber. Please refer to [link / reference needed]. Figure 1 The output end of the first output device 10 is on the right side, and the output end of the second output device 60 is on the left side. The output ends are fused to a quartz end cap coated with an anti-reflection film. The output devices contain texturing areas obtained by etching with abrasive paste or CO2 laser etching, which are used to achieve forward cladding removal and reverse return cladding removal.

[0071] The light from the first pump source 32 and / or the second pump source 42 is generated by semiconductors and output through optical fiber coupling. In this embodiment, the output wavelength of the pump source is 915nm, the output power of the pump source is ≥650W, 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 realize the output of continuous 1080nm laser.

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

[0074] In fiber optic oscillator structures, high laser power density within the fiber can easily lead to nonlinear effects such as stimulated Raman scattering and stimulated Brillouin scattering. This causes most of the energy to be transferred to Stokes light, affecting not only the increase in signal power within the oscillator but also posing a threat to the safety of the upstream system due to the backward transmission of Stokes light. By using multiple pairs of fiber gratings to form a composite resonant cavity 50 within the oscillator, the intensity of nonlinear effects within the fiber can be effectively reduced by introducing multiple wavelengths of light. Furthermore, the effective operating length of the nonlinear effects can be shortened, increasing the nonlinear effect threshold. Therefore, higher output power levels for the oscillator can be achieved.

[0075] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A multi-wavelength laser, characterized in that, The multi-wavelength laser includes a first output device, a cladding optical filter, a first light source assembly, a composite resonant cavity, a second light source assembly, and a second output device, which are connected in sequence via a central fiber. The composite resonant cavity has multiple sub-cavities connected sequentially by the central fiber. The sub-cavities are used to receive light beams emitted by the first light source assembly and / or the second light source assembly, and convert the light beams into laser beams of corresponding wavelengths. 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; The sub-cavity includes two opposing fiber gratings and an active optical fiber disposed between the two fiber gratings. The two ends of the active optical fiber are respectively connected to the two fiber gratings through the central fiber. The center wavelengths of the two corresponding fiber gratings in the sub-cavities are the same, and the center wavelengths of the multiple sub-cavities increase sequentially along the direction from the second output device to the first output device to ensure stable transmission of the laser beam.

2. The multi-wavelength laser as described in claim 1, characterized in that, One of the two fiber gratings is a high-reflection grating, and the other is a low-reflection grating; The high-reflectivity grating is disposed between the active optical fiber and the second output device, and the low-reflectivity grating is disposed between the active optical fiber and the first output device.

3. The multi-wavelength laser as described in claim 2, characterized in that, The high-reflectivity grating has a reflectivity greater than or equal to 99.5%, and the low-reflectivity grating has a reflectivity less than 15%.

4. The multi-wavelength laser as described in claim 1, 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.

5. The multi-wavelength laser as described in any one of claims 1 to 4, characterized in that, The sub-cavity is detachably connected to the central fiber.

6. The multi-wavelength laser as described in claim 1, characterized in that, The first light source component includes: Multiple primary pump sources; A reverse beam combiner, wherein the first beam combining end of the reverse beam combiner is connected to the composite resonant cavity, and the first branch end of the composite resonant cavity is respectively connected to a plurality of the first pump sources and the cladding optical filter.

7. The multi-wavelength laser as described in claim 1, characterized in that, The second light source component includes: Multiple secondary pump sources; A forward combiner, wherein the second combining end of the forward combiner is connected to the composite resonant cavity, and the second branch end of the forward combiner is connected to a plurality of the second pump sources and the second output device respectively.

8. The multi-wavelength laser as described in claim 1, characterized in that, The first output device and / or the second output device are provided with an end cap, and the end cap is provided with an anti-reflection membrane. The interior of the first output device and / or the second output device has a texturing region.

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