A high-power yellow-green laser generation method and a fiber laser

Abstract

This invention relates to the field of laser technology and discloses a method for generating high-power yellow-green laser. The method involves generating pump light from a first seed source and signal light from a second seed source. The pump light and signal light are mixed by a first wavelength division multiplexer, then combined with the light from the first pump source in a beam combiner. The combined beam is then amplified by a first ytterbium-doped fiber to obtain high-power laser light. After collimation by a collimator and dichroism by a first dichroic mirror, the laser light is frequency-doubled by a frequency-doubling crystal and finally dichroically separated by a second dichroic mirror to output high-power yellow-green laser light. This invention discloses a fiber laser for generating high-power yellow-green laser light, which reduces the number of core components in the optical path structure, simplifies the optical path structure and control logic, and reduces the hardware cost and assembly / debugging cost of the equipment. It effectively improves the stimulated Brillouin threshold of the laser and suppresses broadening during spectral amplification, while maintaining stable and good temporal characteristics.

Description

Technical Field

[0001] This invention belongs to the field of high-power laser technology, specifically relating to a method for generating high-power yellow-green laser and a fiber laser. Background Technology

[0002] Yellow-green lasers, with their unique spectral characteristics, hold irreplaceable application value in several cutting-edge fields, including laser displays, biomedicine, Bose-Einstein condensation, and chemical analysis. In the biomedical field, this wavelength is an ideal light source for biological imaging devices such as confocal microscopes and flow cytometers. Its wavelength matches the optical window of biological tissues, enabling high-resolution, low-damage imaging of biological samples. Simultaneously, yellow-green light is also the optimal wavelength choice for laser treatment of complex ophthalmic diseases, precisely targeting diseased tissues while minimizing impact on surrounding healthy tissues, thus showing great promise for clinical applications. Furthermore, the demand for this wavelength of lasers is also growing in fields such as atomic physics research and precision spectral analysis, driving widespread attention to research on related lasers.

[0003] To obtain a yellow-green light source, existing technologies mainly employ two technical approaches:

[0004] The first approach is based on solid-state lasers such as Nd:YAG or Nd:YVO4, which first generate a fundamental frequency light around 1123nm, and then achieve 560nm laser output through intracavity or extracavity frequency doubling technology. However, this approach has significant drawbacks: the energy conversion efficiency during the frequency doubling process is limited, resulting in generally low output power of the 560nm laser, only reaching the level of 0.1~3W, which cannot meet the needs of high-power light sources in fields such as laser display and high-power biotherapy.

[0005] The second approach is based on fiber lasers, utilizing narrow-linewidth Raman fiber amplifiers combined with external frequency doubling to achieve 560nm laser output. This approach typically requires two narrow-linewidth DFB fiber lasers as core components: one with a wavelength of 1064nm, used as a Raman pump source; and another with a wavelength of 1120nm, used as a signal source. After Raman amplification to enhance the power of the 1120nm signal light, it is then frequency-doubled to obtain the 560nm yellow-green light. However, the technical problem with this approach is that, due to the single longitudinal mode characteristics and high side-mode suppression ratio (SBS) of the DFB seed during continuous-wave operation, its spectrum does not support broadening, resulting in a very low SBS threshold, which limits the amplified power.

[0006] Existing yellow-green laser generation technologies cannot simultaneously achieve high power output, high stability, simplified structure, and low-cost control, and there is a lack of a low-cost high-power yellow-green laser technology solution. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of low power and high cost caused by complex structure in the existing high-power yellow-green lasers, thereby providing a high-power yellow-green laser generation method and fiber laser.

[0008] A fiber laser includes a first seed source, a second seed source, a first wavelength division multiplexer, a first pump source, a beam combiner, a first ytterbium-doped fiber, a collimator, a first dichroic mirror, a frequency doubling crystal, and a second dichroic mirror. The outputs of the first and second seed sources are both connected to the input of the first wavelength division multiplexer. The outputs of the first wavelength division multiplexer and the first pump source are both connected to the input of the beam combiner. The beam combiner, the first ytterbium-doped fiber, the collimator, the first dichroic mirror, the frequency doubling crystal, and the second dichroic mirror are connected sequentially.

[0009] The first seed source outputs a first pump light with a center wavelength of a first wavelength, and the second seed source outputs a first signal light with a center wavelength of a second wavelength, wherein the second wavelength is greater than the first wavelength.

[0010] Furthermore, the first wavelength is 1064nm and the second wavelength is 1120nm.

[0011] Furthermore, it also includes a first backlight monitor and a second backlight monitor; the input of the first backlight monitor is connected to the output of the first seed source, and the output of the first backlight monitor is connected to the input of the first wavelength division multiplexer, for monitoring the first pump light generated by the first seed source; the input of the second backlight monitor is connected to the output of the second seed source, and the output of the second backlight monitor is connected to the input of the first wavelength division multiplexer, for monitoring the first signal light generated by the second seed source.

[0012] Furthermore, it also includes a pump light stripper; the input end of the pump light stripper is connected to the output end of the first ytterbium-doped fiber, and the output end of the pump light stripper is connected to the input end of the collimator, used to strip the fourth wavelength of the laser in the power amplification laser output from the first ytterbium-doped fiber with the center wavelength of the second wavelength, and input it into the collimator.

[0013] Furthermore, the first seed source includes a broadband superfluorescent fiber source connected to a first bandpass filter, used to output a first pump light with a center wavelength of a first wavelength.

[0014] The broadband superfluorescent fiber source includes a coupler, a second wavelength division multiplexer, a second ytterbium-doped fiber, an isolator, a first amplifier, and a first bandpass filter connected in sequence. It also includes a second pump source with a center wavelength of the fourth wavelength connected to the second wavelength division multiplexer for outputting the first pump light.

[0015] Furthermore, the center wavelength of the broadband superfluorescent fiber source of the first seed source is the first wavelength, and the 3dB linewidth is 10-25nm.

[0016] Furthermore, the first seed source includes a superfluorescent semiconductor laser, an optical isolator, a first amplifier, and a first bandpass filter connected in sequence, for outputting a first pump light with a center wavelength of a first wavelength.

[0017] Furthermore, the second seed source includes a single-frequency fiber laser with a center wavelength of the second wavelength, a phase modulator, a second amplifier, and a second bandpass filter connected in sequence. The phase modulator is connected to a white noise source and is used to output a first signal light with a center wavelength of the second wavelength.

[0018] A high-power yellow-green laser generation method, based on the aforementioned fiber laser, includes the following steps: generating a first pump light with a center wavelength of a first wavelength through a first seed source, and generating a first signal light with a center wavelength of a second wavelength through a second seed source; mixing the first pump light and the first signal light through a first wavelength division multiplexer, and then combining them with the output laser of the first pump source in a beam combiner; amplifying the combined light of the beam combiner through a first ytterbium-doped fiber to obtain a power-amplified laser with a center wavelength of the second wavelength; collimating the power-amplified laser with a center wavelength of the second wavelength through a collimator, and separating the lasers with center wavelengths of the first, second, and fourth wavelengths through a first dichroic mirror to obtain a dichroic laser with a center wavelength of the second wavelength; frequency doubling the dichroic laser with a center wavelength of the second wavelength through a frequency-doubling crystal to obtain a laser with a center wavelength of the third wavelength; and performing dichroic processing through a second dichroic mirror to obtain a dichroic laser with a center wavelength of the third wavelength.

[0019] Furthermore, the third wavelength is 560nm, and the fourth wavelength is 976nm.

[0020] Beneficial effects: This invention discloses a fiber laser for generating high-power yellow-green lasers. It reduces the number of core components in the optical path structure, simplifies the optical path structure and control logic, and reduces the hardware cost and assembly and debugging cost of the equipment, making it more conducive to industrial mass production and application.

[0021] By optimizing the spectral modulation design and coordinating it with the pump source, the SBS threshold of the long-gain fiber was significantly improved, breaking through the limitation of the SBS effect on power enhancement in the existing technology; the 1120nm laser power after power amplification by the first ytterbium-doped fiber was effectively improved.

[0022] Based on the optical path device structure of this invention, a first seed source of a 1064nm band light source is selected as the pump source of the 1120nm Raman signal light. Through the synergistic effect of beam combining with the 1120nm Raman signal light based on phase modulation, the 1120nm Raman signal light can maintain a good linewidth during amplification, effectively suppressing the spectral distortion caused by the quasi-degenerate four-wave mixing effect and the self-phase modulation effect, ensuring the narrow linewidth characteristics of the amplified 1120nm Raman signal light, thus it can be used as a fundamental frequency light source, and high-power 560nm yellow-green light output can be achieved through frequency doubling. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the fiber laser structure of the present invention;

[0025] Figure 2 This is a schematic diagram of a first seed source structure according to the present invention;

[0026] Figure 3 This is a schematic diagram of another first seed source structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the second seed source structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the spectrum of the first seed source of the present invention;

[0029] Figure 6 This is a schematic diagram of the spectrum of the second seed source of the present invention;

[0030] Figure 7 This is a schematic diagram of the spectrum of the fiber laser of the present invention;

[0031] Figure 8 This is the time-domain stability curve of the first seed source under different bandwidth conditions in this invention.

[0032] Figure descriptions: 11. First seed source; 12. First backlight monitor; 21. Second seed source; 22. Second backlight monitor; 31. First wavelength division multiplexer; 32. Bundle combiner; 321. First pump source; 33. First ytterbium-doped fiber; 34. Pump light stripper; 35. Collimator; 36. First dichroic mirror; 37. Frequency doubling crystal; 38. Second dichroic mirror;

[0033] 111. Coupler; 112. Second wavelength division multiplexer; 113. Second pump source; 114. Second ytterbium-doped fiber; 115. Isolator; 116. First amplifier; 117. First bandpass filter;

[0034] 211. Single-frequency fiber laser; 212. Phase modulator; 213. White noise source; 214. Second amplifier; 215. Second bandpass filter. Detailed Implementation

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] Example 1:

[0039] Reference Figure 1As shown, this embodiment provides a fiber laser, which includes a first seed source 11, a second seed source 21, a first wavelength division multiplexer 31, a first pump source 321, a combiner 32, a first ytterbium-doped fiber 33, a collimator 35, a first dichroic mirror 36, a frequency doubling crystal 37, and a second dichroic mirror 38. The output terminals of the first seed source 11 and the second seed source 21 are both connected to the input terminal of the first wavelength division multiplexer 31. The output terminals of the first wavelength division multiplexer 31 and the first pump source 321 are both connected to the input terminal of the combiner 32. The combiner 32, the first ytterbium-doped fiber 33, the collimator 35, the first dichroic mirror 36, the frequency doubling crystal 37, and the second dichroic mirror 38 are connected sequentially.

[0040] The first seed source 11 outputs a first pump light with a center wavelength of the first wavelength, and the second seed source 21 outputs a first signal light with a center wavelength of the second wavelength, the second wavelength being greater than the first wavelength.

[0041] In this embodiment, the first wavelength is 1064nm and the second wavelength is 1120nm.

[0042] As a further improvement to this embodiment, a first backlight monitor 12 and a second backlight monitor 22 are also included. The input terminal of the first backlight monitor 12 is connected to the output terminal of the first seed source 11, and the output terminal of the first backlight monitor 12 is connected to the input terminal of the first wavelength division multiplexer 31, for monitoring the first pump light generated by the first seed source 11. The input terminal of the second backlight monitor 22 is connected to the output terminal of the second seed source 21, and the output terminal of the second backlight monitor 22 is connected to the input terminal of the first wavelength division multiplexer 31, for monitoring the first signal light generated by the second seed source 21. The first backlight monitor 12 and the second backlight monitor 22 are used to monitor the backlight power increase of the two paths and to determine whether the laser is abnormal.

[0043] As a further improvement to this embodiment, a pump light stripper 34 is also included. The input end of the pump light stripper 34 is connected to the output end of the first ytterbium-doped fiber 33, and the output end of the pump light stripper 34 is connected to the input end of the collimator 35. It is used to strip the fourth wavelength laser light from the power-amplified laser light with a center wavelength of the second wavelength output from the first ytterbium-doped fiber 33, and input it into the collimator 35. The pump light stripper 34 can remove the unabsorbed residual pump light in the first ytterbium-doped fiber 33, thereby improving the purity of the laser output.

[0044] As the working principle of the fiber laser in this embodiment, the first seed source 11 generates a first pump light with a center wavelength of 1064nm, and the second seed source 21 generates a first signal light with a center wavelength of 1120nm. The first pump light with a center wavelength of 1064nm and the first signal light with a center wavelength of 1120nm pass through the first return light monitor 12 and the second return light monitor 22, respectively, and then the seed light is mixed by the first wavelength division multiplexer 31. The mixed seed light is then combined with the output laser of the first pump source 321 at the beam combiner 32, wherein the first pump source 321 provides pump pump guarantee for the first seed source 11 and the second seed source 21. The mixed laser after beam combining passes sequentially through the first ytterbium-doped fiber 33, the pump light stripper 34, the collimator 35, and the first... Dichroic mirror 36: The first ytterbium-doped fiber 33 amplifies the power of the mixed laser, outputting a high-power laser with a center wavelength of 1120nm; the pump light stripper 34 specifically removes the 976nm pump light from the mixed laser; the collimator 35 collimates and calibrates the laser after stripping; the first dichroic mirror 36 separates the 1120nm laser with a center wavelength from the remaining 976nm and 1064nm lasers to obtain a pure laser with a center wavelength of 1120nm; the frequency doubling crystal 37 performs frequency doubling on the pure laser with a center wavelength of 1120nm to generate a high-power laser with a center wavelength of 560nm; after being separated again by the second dichroic mirror 38, a pure high-power laser with a center wavelength of 560nm is finally output.

[0045] Reference Figure 2 As shown, in one embodiment of this example, the first seed source 11 includes a broadband superfluorescent fiber source connected to a first bandpass filter, used to output a first pump light with a center wavelength of the first wavelength.

[0046] The broadband superfluorescent fiber source includes a coupler 111, a second wavelength division multiplexer 112, a second ytterbium-doped fiber 114, an isolator 115, a first amplifier 116, and a first bandpass filter 117 connected in sequence. It also includes a second pump source 113 with a center wavelength of the fourth wavelength, connected to the second wavelength division multiplexer 112, for outputting the first pump light. Therefore, the first seed source 11 has the characteristics of wide bandwidth and low temporal coherence.

[0047] In a preferred embodiment, the coupler 111 includes a fiber loop reflector, constructed by splicing the two output ports of a 50 / 50 coupler, which can provide high reflectivity. The second ytterbium-doped fiber 114 is a 6 / 125μm YDF and can serve as a gain medium. By using BPFs with different bandwidths, the linewidth of the Raman-pumped laser can be changed, and a suitable spectral width of the SFSs source can be selected so that the fiber laser can output high-power 1120nm narrow-linewidth laser.

[0048] In this embodiment, the first seed source 11 controls the output power to 2~4W by adjusting the amplifier current.

[0049] Reference Figure 3 As shown, in another embodiment of this example, the first seed source 11 includes a superfluorescent semiconductor laser (SLD), an optical isolator (ISO), a first amplifier (116), and a first bandpass filter (117) connected in sequence, for outputting a first pump light with a center wavelength of a first wavelength. Thus, the first seed source 11 has a wide spectral bandwidth while exhibiting low temporal coherence.

[0050] In this implementation, the butterfly-packaged semiconductor seed source laser, or super-fluorescent semiconductor laser (SLD), has a wide spectral bandwidth and low temporal coherence, with a spectral bandwidth of 10~40nm.

[0051] The two first seed sources 11 selected in this embodiment do not require the addition of a phase modulator to generate the first pump light that meets the requirements, thereby reducing the structural complexity of the entire laser and reducing equipment costs.

[0052] Reference Figure 5 As shown, in this embodiment, the center wavelength of the broadband superfluorescent fiber source (SFSs) of the first seed source 11 is around 1064.0 nm, and the 3dB linewidth reaches about 10~40 nm. Due to the limitation of the available BPF bandwidth, different BPFs can be used for bandwidth filtering to achieve laser output with different spectral widths.

[0053] Tests revealed that SFS light sources with different bandwidths exhibited varying temporal stability during amplification. The temporal stability under low bandwidth conditions was significantly worse than that under wide bandwidth conditions, and temporal stability had a significant impact on the linewidth of the light source ultimately converted to an 1120nm Raman wavelength.

[0054] Reference Figure 8 For the first seed source 11, the horizontal axis represents time, and the vertical axis represents the normalized time trace, used to characterize temporal stability. With 3dB bandwidths of 2nm, 8nm, and 16nm, it is evident that the SFS light source with a bandwidth of 16nm exhibits significantly better temporal stability, ultimately resulting in a narrower linewidth for the converted 1120nm Raman wavelength light source. Therefore, in this embodiment, the first seed source 11 uses a light source with a 3dB linewidth of 10-25nm.

[0055] Reference Figure 4As shown, in this embodiment, the second seed source 21 includes a single-frequency fiber laser 211 with a center wavelength of the second wavelength, a phase modulator 212, a second amplifier 214, and a second bandpass filter 215 connected in sequence. The phase modulator 212 is connected to a white noise source 213 and is used to output a first signal light with a center wavelength of the second wavelength. The first signal light is a narrow linewidth laser with a center wavelength of the second wavelength.

[0056] In the second seed source 21, a single-frequency fiber laser 211 with a center wavelength of the second wavelength, a phase modulator 212, a second amplifier 214, and a second bandpass filter 215 are connected in sequence, and a white noise source 213 is connected to the phase modulator 212 to output a first signal light with a center wavelength of the second wavelength. The first signal light is a narrow linewidth laser with a center wavelength of the second wavelength.

[0057] Specifically, the 1120nm single-frequency fiber laser 211, driven by an amplified white noise signal, undergoes spectral broadening at 1120nm via an electro-optic phase modulator 212, resulting in a linewidth of 0.1~0.2nm, before being amplified to 4W. A second bandpass filter 215 is used to filter out amplified spontaneous emission noise and sideband noise in the Raman signal laser.

[0058] Reference Figure 6 As shown, in this embodiment, the center wavelength of the obtained second seed source 21 is around 1120 nm, and the 3 dB spectral linewidth is about 0.15 nm, which is sufficient to effectively suppress the SBS effect.

[0059] As a preferred embodiment, the output optical fibers of the second seed source 21 are all 10 / 125μm (core / cladding diameter) passive optical fibers.

[0060] In this embodiment, a broadband superfluorescent fiber source (SFSs) with a 3dB linewidth of 10-25 nm and a center wavelength of 1064.0 nm is designated as the first seed source; a seed source with a 3dB spectral linewidth of 0.1 nm to 0.2 nm and a center wavelength of 1120 nm is designated as the second seed source. Preferably, the 3dB spectral linewidth of the second seed source is 0.15 nm.

[0061] In practical applications, an excessively wide spectral width of the superfluorescent light source can lead to excessively low gain of the Raman signal light. A suitable width is crucial for simultaneously achieving high Raman signal light amplification and ensuring a narrow linewidth of the Raman signal light. Therefore, this embodiment provides a specific implementation method, where the specific parameters of the selected first seed source 11 and second seed source 21 ensure that, while guaranteeing a high gain of the Raman signal light, the final light source converted to an 1120nm Raman wavelength has a narrow linewidth.

[0062] Reference Figure 7 As shown, broadband superfluorescent fiber sources (SFSs) with a center wavelength of 1064nm and different bandwidths are used as the first seed source 11. When combined with the second seed source 21 with a 3dB linewidth of 10-25nm, better linewidth maintenance can be achieved.

[0063] Through the specific design of the above-described high-power yellow-green laser generation method, in one embodiment of this example, a broadband superfluorescent fiber source (SFSs) with a 3dB linewidth of 10-25nm and a center wavelength of 1064.0nm is used as the first seed source 11. It is then mixed with a second seed source 21 with a 3dB spectral linewidth of approximately 0.15nm and a center wavelength of 1120nm. After power amplification, a high-power, narrow-linewidth 1120nm fundamental frequency light of kilowatt level or above can be obtained. This high-power, narrow-linewidth 1120nm fundamental frequency light has a high frequency doubling conversion efficiency. Finally, after frequency doubling, a high-power 560nm yellow-green laser can be generated.

[0064] Example 2:

[0065] This embodiment provides a method for generating high-power yellow-green laser, based on the fiber laser of Embodiment 1, and includes the following steps:

[0066] A wide-bandwidth laser with a center wavelength near the first wavelength is generated by the first seed source 11 and used as the pump light for the subsequent beam combining laser system; a narrow-band laser with a center wavelength of the second wavelength is generated by the second seed source 21 and used as the signal light for the subsequent beam combining laser system.

[0067] The first pump light and the first signal light are mixed by the first wavelength division multiplexer 31 and then combined with the output laser of the first pump source 321 in the beam combiner 32.

[0068] The combined light from the combiner 32 is amplified by the first ytterbium-doped fiber 33 to obtain a laser with a center wavelength of the second wavelength.

[0069] The collimator 35 collimates the laser with the center wavelength of the second wavelength after power amplification, and the first dichroic mirror 36 separates the lasers with the center wavelengths of the first wavelength, the second wavelength and the fourth wavelength, to obtain the laser with the center wavelength of the second wavelength after color separation.

[0070] The laser with a center wavelength of the second wavelength after color separation is frequency doubled by the frequency doubling crystal 37 to obtain a laser with a center wavelength of the third wavelength.

[0071] The second dichroic mirror 38 is used for color separation to obtain a laser with a center wavelength of the third wavelength after color separation.

[0072] In this embodiment, the third wavelength is 560nm and the fourth wavelength is 976nm.

[0073] 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.

[0074] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A fiber laser, characterized by, The fiber laser includes a first seed source, a second seed source, a first wavelength division multiplexer, a first pump source, a combiner, a first ytterbium-doped fiber, a collimator, a first dichroic mirror, a frequency doubling crystal, and a second dichroic mirror. The outputs of the first seed source and the second seed source are both connected to the input of the first wavelength division multiplexer. The outputs of the first wavelength division multiplexer and the first pump source are both connected to the input of the combiner. The combiner, the first ytterbium-doped fiber, the collimator, the first dichroic mirror, the frequency doubling crystal, and the second dichroic mirror are connected sequentially. The first seed source includes a broadband superfluorescent fiber source connected to a first bandpass filter; the broadband superfluorescent fiber source includes a coupler, a second wavelength division multiplexer, a second ytterbium-doped fiber, an isolator, a first amplifier and a first bandpass filter connected in sequence, and also includes a second pump source with a center wavelength of a fourth wavelength connected to the second wavelength division multiplexer; The first seed source outputs a first pump light with a center wavelength of a first wavelength and a 3dB linewidth of 10-25nm, and the second seed source outputs a first signal light with a center wavelength of a second wavelength and a 3dB linewidth of 0.1-0.2nm, wherein the second wavelength is 1120nm and is greater than the first wavelength.

2. The fiber laser of claim 1, wherein, The first wavelength is 1064 nm.

3. The fiber laser of claim 1, wherein, It also includes a first backlight monitor and a second backlight monitor; the input of the first backlight monitor is connected to the output of the first seed source, and the output of the first backlight monitor is connected to the input of the first wavelength division multiplexer, for monitoring the first pump light generated by the first seed source. The input terminal of the second backlight monitor is connected to the output terminal of the second seed source, and the output terminal of the second backlight monitor is connected to the input terminal of the first wavelength division multiplexer, for monitoring the first signal light generated by the second seed source.

4. The fiber laser of claim 1, wherein, It also includes a pump light stripper; the input end of the pump light stripper is connected to the output end of the first ytterbium-doped fiber, and the output end of the pump light stripper is connected to the input end of the collimator, used to strip the fourth wavelength of the laser in the power amplification laser output from the first ytterbium-doped fiber with the center wavelength of the second wavelength, and input it into the collimator.

5. The fiber laser of claim 1, wherein, The second seed source includes a single-frequency fiber laser with a center wavelength of the second wavelength, a phase modulator, a second amplifier, and a second bandpass filter connected in sequence. The phase modulator is connected to a white noise source and is used to output a first signal light with a center wavelength of the second wavelength.

6. A method for generating high power yellow-green laser light, the yellow-green laser light is generated based on the fiber laser of any one of claims 1-5, characterized in that, Includes the following steps: A first pump light with a center wavelength of a first wavelength is generated by a first seed source, and a first signal light with a center wavelength of a second wavelength is generated by a second seed source. The first pump light and the first signal light are mixed by a first wavelength division multiplexer and then combined with the output laser of the first pump source in a beam combiner. The combined light from the beam combiner is amplified by a first ytterbium-doped fiber to obtain a laser with a center wavelength of a second wavelength. The amplified laser with a center wavelength of a second wavelength is collimated by a collimator, and the lasers with center wavelengths of the first, second, and fourth wavelengths are separated by a first dichroic mirror to obtain a laser with a center wavelength of a second wavelength after separation. The laser with a center wavelength of a second wavelength after separation is frequency-doubled by a frequency-doubling crystal to obtain a laser with a center wavelength of a third wavelength. Finally, the laser with a center wavelength of a third wavelength is separated by a second dichroic mirror.

7. A method for generating high-power yellow-green laser according to claim 6, characterized in that, The third wavelength is 560nm, and the fourth wavelength is 976nm.

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