Multi-wavelength visible light source for improving spectral performance by using mixed nonlinear process

Abstract

Aiming at the defect that visible light output with customizable spectrum is difficult to realize by the existing tunable visible light source, the invention provides a multi-wavelength visible light source for improving spectrum performance by using a mixed nonlinear process, and the requirement of quasi-phase matching is greatly relaxed by using a chirp polarization period lithium niobate waveguide. Furthermore, in combination with a chirp polarization period lithium niobate waveguide and an acousto-optic adjustable filter, the defect that the number of filter channels is limited can be overcome by utilizing a mixed nonlinear process (including frequency multiplication and sum frequency), the number of output wavelengths is greatly expanded, and meanwhile, the output spectrum has the characteristics of adjustable wavelength number, intensity, interval and line width; and multi-wavelength visible light output with flexibly adjustable spectrum is realized.

Description

Technical Field

[0001] The present invention mainly relates to the field of optical fiber laser technology, and in particular to a multi-wavelength visible light source that utilizes a hybrid nonlinear process to enhance spectral performance. Background Art

[0002] Fiber lasers with flexibly adjustable spectra have wide applications in wavelength division multiplexing communications, laser biomedicine, hyperspectral imaging, photoacoustic spectroscopy, and laser pumping. In particular, light sources with flexibly adjustable spectra in the visible light band have applications in fiber optic sensing, medical imaging, multispectral lidar, and so on.

[0003] The spectrum can be flexibly controlled, including the realization of multi-wavelength output, adjustable number of wavelengths, independently tunable line width and intensity of each wavelength, and tunable wavelength intervals. Researchers use nonlinear effects such as four-wave mixing, cascaded stimulated Brillouin scattering, or filter structures such as Lyot filters, Sagnac rings, MZ interferometers, FP interferometers, etc. to achieve multi-wavelength output. However, limited by the gain band of rare earth ions in gain fibers, lasers can usually only operate in the infrared band. At the same time, due to the limitations of filtering principles, it is difficult to achieve spectral control in multiple dimensions at the same time. Therefore, it is difficult to meet the needs of wavelength division multiplexing communications, partially coherent optical imaging, and other applications that require spectral shape and light source coherence. In the acousto-optic tunable filter, the number of output wavelengths, wavelength intervals, intensity and other parameters can be independently controlled by adjusting parameters such as the frequency, intensity and number of channels of the RF signal.

[0004] A mature technology for achieving visible light output is nonlinear frequency conversion. However, it is limited by the strict quasi-phase matching bandwidth requirements. The shift in wavelength and the increase in linewidth will lead to a decrease in output power, making it difficult to achieve spectrally customizable visible light output. Summary of the invention

[0005] In view of the defect that existing tunable visible light sources are difficult to achieve spectrally customizable visible light output, the present invention provides a multi-wavelength visible light source that utilizes a hybrid nonlinear process to improve spectral performance, and utilizes a chirped polarization period lithium niobate waveguide to greatly relax the requirements for quasi-phase matching. Furthermore, in combination with a chirped polarization period lithium niobate waveguide and an acousto-optic tunable filter, a hybrid nonlinear process (including frequency doubling and sum frequency) can be utilized to overcome the disadvantage of a limited number of filter channels, greatly expand the number of output wavelengths, and at the same time, the output spectrum has the characteristics of adjustable wavelength number, intensity, interval, and line width, thereby achieving multi-wavelength, spectrally flexibly adjustable visible light output.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a multi-wavelength visible light source that utilizes a hybrid nonlinear process to enhance spectral performance, comprising a seed source with customizable spectrum, an optical fiber amplifier, a chirped polarization period lithium niobate waveguide, a wavelength division multiplexer, a fundamental frequency light output end, and a visible light output end;

[0008] The spectrally customizable seed source outputs seed light of a required spectrum; the spectrally customizable seed source is connected to the input end of the optical fiber amplifier, the output end of the optical fiber amplifier is connected to the input end of the chirped polarization period lithium niobate waveguide, the output end of the chirped polarization period lithium niobate waveguide is connected to the input end of the wavelength division multiplexer, one output end of the wavelength division multiplexer is connected to the baseband light output end, and the other output end of the wavelength division multiplexer is connected to the visible light output end.

[0009] In the present invention: a seed source with customizable spectrum outputs seed light of required spectrum; the seed light output by the seed source with customizable spectrum is injected into the optical fiber amplifier to obtain high-power fundamental frequency light output; the fundamental frequency light output by the optical fiber amplifier is injected into the chirped polarization period lithium niobate waveguide, nonlinear frequency conversion occurs, and the multi-wavelength visible light output with customizable spectrum is obtained; wherein the wavelength range corresponding to the polarization period of the chirped polarization period lithium niobate waveguide needs to cover the range of required spectrum. The wavelength division multiplexer separates the fundamental frequency light from the visible light, the fundamental frequency light is output from the fundamental frequency light output end, and the visible light is output from the visible light output end.

[0010] Preferably, the spectrum-customizable seed source comprises a superfluorescent fiber light source and an acousto-optic tunable filter, the superfluorescent fiber light source is connected to the input end of the acousto-optic tunable filter, and the output end of the acousto-optic tunable filter is connected to the input end of the fiber amplifier. The superfluorescent fiber light source provides an initial seed light, and the transmission spectrum of the initial seed light is customized according to the required spectrum through the acousto-optic tunable filter to achieve customized output of the spectrum of the superfluorescent seed source, and the method comprises: first determining the required spectrum of the superfluorescent seed source, and then setting the number of radio frequency channels and the radio frequency intensity of the acousto-optic tunable filter according to the required spectrum of the superfluorescent seed source; the initial seed light achieves customized output of the spectrum of the superfluorescent seed source through the acousto-optic tunable filter.

[0011] Preferably, another implementation of the spectrally customizable seed source, the spectrally customizable seed source comprises an acousto-optic tunable filter, a semiconductor laser, an (N+1)×1 optical fiber pump / signal combiner, an ytterbium-doped optical fiber, an optical fiber coupler and an optical fiber isolator;

[0012] There are N semiconductor lasers, where N is greater than or equal to 1; the fiber coupler is a fiber coupler capable of splitting an input light beam into two output light beams according to a certain splitting ratio;

[0013] The output pigtails of N semiconductor lasers are connected to N pump arms of (N+1)×1 optical fiber pump / signal combiner, the combining end of the optical fiber pump / signal combiner is connected to the input end of the ytterbium-doped optical fiber, the output end of the ytterbium-doped optical fiber is connected to the input end of the optical fiber coupler, the optical fiber coupler has two output ends, the first output end of the optical fiber coupler is connected to an acousto-optic tunable filter, the acousto-optic tunable filter is connected to an optical fiber isolator and then connected to the signal input arm of the (N+1)×1 optical fiber pump / signal combiner; the second output end of the optical fiber coupler is connected to the input end of the optical fiber amplifier;

[0014] The (N+1)×1 fiber pump / signal combiner, ytterbium-doped fiber, fiber coupler, acousto-optic tunable filter, and fiber isolator are connected into a ring cavity. The acousto-optic tunable filter provides laser gain feedback in the ring cavity, and the fiber isolator is used to block the reverse traveling wave.

[0015] The present invention provides a multi-wavelength visible light source that uses a hybrid nonlinear process to improve spectral performance. By combining the spectral control capability of the filter and the hybrid nonlinear process in the chirped polarization period lithium niobate waveguide, the output of the number of visible light wavelengths can be greatly expanded while maintaining good spectral control capabilities. Compared with the common tunable visible light source in the prior art, the present invention can achieve the following technical effects:

[0016] Compared with multi-wavelength lasers based on other technologies, the present invention uses an acousto-optic tunable filter to achieve more flexible spectrum customization, such as adjustable wavelength number, intensity, and interval.

[0017] The present invention utilizes the hybrid nonlinear process of the chirped lithium niobate waveguide to greatly expand the number of wavelengths output by the light source, thereby compensating for the shortcoming that the number of output wavelengths of the acousto-optic tunable filter is small. Specifically, when the number of input wavelengths of the chirped polarization period lithium niobate waveguide is m, the number of output wavelengths of the chirped polarization period lithium niobate waveguide is at most m+0.5*m! / (m-2)! . BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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.

[0019] Figure 1 A structural diagram of a light source provided in Embodiment 1 of the present invention;

[0020] Figure 2 A structural diagram of a light source provided in Embodiment 2 of the present invention;

[0021] Figure 3 This is a schematic diagram of the principle of Embodiment 1 of the present invention;

[0022] Figure 4 This is a schematic diagram of the principle of Example 2 of the present invention.

[0023] Description of Figure Numbers:

[0024] 1. Superfluorescent fiber light source; 2. Acousto-optic tunable filter; 3. Fiber amplifier; 4. Chirped polarization period lithium niobate waveguide; 5. Wavelength division multiplexer; 6. Fundamental frequency light output end; 7. Visible light output end; 8. Semiconductor laser; 9. (N+1)×1 fiber pump / signal combiner; 10. Ytterbium-doped fiber; 11. Fiber coupler; 12. Fiber isolator.

[0025] 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

[0026] 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.

[0027] The present invention provides a multi-wavelength visible light source that utilizes a hybrid nonlinear process to enhance spectral performance, comprising a spectrally customizable seed source, an optical fiber amplifier 3, a chirped polarization period lithium niobate waveguide 4, a wavelength division multiplexer 5, a baseband light output end 6, and a visible light output end 7. The spectrally customizable seed source outputs seed light of a required spectrum. The spectrally customizable seed source is connected to the input end of the optical fiber amplifier 3, the output end of the optical fiber amplifier 3 is connected to the input end of the chirped polarization period lithium niobate waveguide 4, the output end of the chirped polarization period lithium niobate waveguide 4 is connected to the input end of the wavelength division multiplexer 5, one output end of the wavelength division multiplexer 5 is connected to the baseband light output end 6, and the other output end of the wavelength division multiplexer 5 is connected to the visible light output end 7.

[0028] The seed source with customizable spectrum outputs seed light with required spectrum;

[0029] The seed light outputted by the spectrally customizable seed source is injected into the optical fiber amplifier 3 to obtain a high-power spectrally customizable fundamental frequency light output.

[0030] The fundamental frequency light output by the optical fiber amplifier 3 is injected into the chirped polarization period lithium niobate waveguide 4, and nonlinear frequency conversion (including sum frequency and frequency doubling) occurs to obtain a multi-wavelength visible light output with customizable spectrum.

[0031] The wavelength division multiplexer 5 separates the fundamental frequency light from the visible light. The fundamental frequency light is output from the fundamental frequency light output terminal 6 , and the visible light is output from the visible light output terminal 7 .

[0032] Embodiment 1:

[0033] like Figure 1 As shown, a multi-wavelength visible light source that utilizes a hybrid nonlinear process to enhance spectral performance is provided, including a superfluorescent fiber light source 1, an acousto-optic tunable filter 2, an optical fiber amplifier 3, a chirped polarization period lithium niobate waveguide 4, a wavelength division multiplexer 5, a baseband light output end 6, and a visible light output end 7. The superfluorescent fiber light source 1 and the acousto-optic tunable filter 2 constitute a seed source of the present embodiment in which the spectrum can be customized.

[0034] The superfluorescent fiber light source 1 is connected to the input end of the acousto-optic tunable filter 2, the output end of the acousto-optic tunable filter 2 is connected to the input end of the fiber amplifier 3, the output end of the fiber amplifier 3 is connected to the input end of the chirped polarization period lithium niobate waveguide 4, the output end of the chirped polarization period lithium niobate waveguide 4 is connected to the input end of the wavelength division multiplexer 5, one output end of the wavelength division multiplexer 5 is connected to the baseband light output end 6, and the other output end of the wavelength division multiplexer 5 is connected to the visible light output end 7.

[0035] The working process of this embodiment:

[0036] The superfluorescent fiber light source 1 provides an initial seed light, and the transmission spectrum of the initial seed light is customized through an acousto-optic tunable filter to achieve customized output of the spectrum of the superfluorescent seed source, including: first determining the required spectrum of the superfluorescent seed source, and then setting the number of radio frequency channels and the radio frequency intensity of the acousto-optic tunable filter according to the required spectrum of the superfluorescent seed source; the initial seed light achieves customized output of the spectrum of the superfluorescent seed source through the acousto-optic tunable filter.

[0037] Further, the number of radio frequency channels and radio frequency intensity of the acousto-optic tunable filter are set according to the spectrum of the required superfluorescence seed source, and the method includes:

[0038] Assume that the AOTF has a total of n available RF channels;

[0039] According to the wavelength number m of the spectrum of the required superfluorescence seed source, the number m of radio frequency channels of the acousto-optic tunable filter is set, where m is less than or equal to n;

[0040] Determine the radio frequency frequencies of the m radio frequency channels enabled by the acousto-optic tunable filter according to the m wavelengths in the spectrum of the required superfluorescence seed source and the correspondence between the radio frequency of the acousto-optic tunable filter and the output wavelength;

[0041] The output wavelength and RF intensity of each RF channel are determined based on the RF frequency and RF intensity of each RF channel enabled by the acousto-optic tunable filter.

[0042] If a wide spectrum output is required, multiple RF channels with similar RF frequencies are set so that multiple wavelengths partially overlap to obtain a linewidth tunable output.

[0043] The seed light output by the acousto-optic tunable filter 2 is injected into the optical fiber amplifier 3 to obtain a high-power fundamental frequency light output with customizable spectrum.

[0044] The fundamental frequency light output by the optical fiber amplifier 3 is injected into the chirped polarization period lithium niobate waveguide 4, where nonlinear frequency conversion occurs to obtain a multi-wavelength visible light output with customizable spectrum. Figure 3 As shown, the mixing and frequency doubling process will make the frequency f i and f j The fundamental frequency light is also generated with a frequency of 2f i and 2f j The doubled frequency light and the frequency f i +f j The sum frequency light can be used to expand the number of wavelengths.

[0045] The wavelength division multiplexer 5 separates the fundamental frequency light from the visible light. The fundamental frequency light is output from the fundamental frequency light output terminal 6 , and the visible light is output from the visible light output terminal 7 .

[0046] Embodiment 2:

[0047] like Figure 2 As shown, a multi-wavelength visible light laser with customizable all-fiber spectrum is provided, including an acousto-optic tunable filter 2, an optical fiber amplifier 3, a chirped polarization period lithium niobate waveguide 4, a wavelength division multiplexer 5, a fundamental frequency light output end 6, a visible light output end 7, a semiconductor laser 8, an (N+1)×1 optical fiber pump / signal combiner 9, an ytterbium-doped optical fiber 10, an optical fiber coupler 11, and an optical fiber isolator 12. There are N semiconductor lasers 8, where N is greater than or equal to 1. The optical fiber coupler 11 is an optical fiber coupler that can split an input light beam into two output light beams according to a certain splitting ratio. In practical applications, optical fiber couplers with different splitting ratios are used according to requirements.

[0048] The output tail fibers of N semiconductor lasers 8 are connected to the N pump arms of (N+1)×1 optical fiber pump / signal combiner 9. The beam combining end of the optical fiber pump / signal combiner 9 is connected to the input end of the ytterbium-doped optical fiber 10. The output end of the ytterbium-doped optical fiber 10 is connected to the input end of the optical fiber coupler 11. The optical fiber coupler 11 has two output ends. The first output end of the optical fiber coupler 11 is connected to the acousto-optic tunable filter 2. The acousto-optic tunable filter 2 is connected to the optical fiber isolator 12 and then connected to the signal input arm of the (N+1)×1 optical fiber pump / signal combiner 9. The (N+1)×1 optical fiber pump / signal combiner 9, the ytterbium-doped optical fiber 10, the optical fiber coupler 11, the acousto-optic tunable filter 2, and the optical fiber isolator 12 are connected to form a ring cavity. The acousto-optic tunable filter 2 provides laser gain feedback in the ring cavity. The optical fiber isolator 12 is used to block the reverse traveling wave.

[0049] The acousto-optic tunable filter 2, the semiconductor laser 8, the (N+1)×1 optical fiber pump / signal combiner 9, the ytterbium-doped optical fiber 10, the optical fiber coupler 11 and the optical fiber isolator 12 together constitute a seed source with customizable spectrum.

[0050] The lasers output by N semiconductor lasers 8 are coupled into the ytterbium-doped fiber 10 through the (N+1)×1 fiber pump / signal combiner 9, and a wide spectrum of ASE (amplified spontaneous emission) light is excited. The ytterbium-doped fiber 10 is split by the fiber coupler 11, and a small portion of the laser is separated and enters the acousto-optic tunable filter 2 through the first output end of the fiber coupler 11. The number of RF channels and the RF intensity of the acousto-optic tunable filter 2 are set according to the required spectrum, so as to realize the customizable output of the seed source output seed laser spectrum of the customizable spectrum. The acousto-optic tunable filter 2 outputs the laser of the required spectral shape, and then passes through the fiber isolator 12, and is coupled into the ytterbium-doped fiber 10 by the fiber pump / signal combiner 9, providing laser gain feedback, so that the laser with the required spectrum is further enhanced to form laser oscillation, which is output from the second output end of the fiber coupler 11.

[0051] The second output end of the optical fiber coupler 11 is connected to the input end of the optical fiber amplifier 3, the output end of the optical fiber amplifier 3 is connected to the input end of the chirped polarization period lithium niobate waveguide 4, the output end of the chirped polarization period lithium niobate waveguide 4 is connected to the input end of the wavelength division multiplexer 5, one output end of the wavelength division multiplexer 5 is connected to the baseband light output end 6, and the other output end of the wavelength division multiplexer 5 is connected to the visible light output end 7.

[0052] The number of radio frequency channels and radio frequency intensity of the acousto-optic tunable filter 2 are set according to the required spectrum to achieve customizable output of the seed source output seed laser spectrum with customizable spectrum, and the method includes:

[0053] Assume that the AOTF has a total of n available RF channels;

[0054] According to the number m of wavelengths of the required spectrum, the number m of radio frequency channels of the acousto-optic tunable filter is set, where m is less than or equal to n;

[0055] Determine the radio frequency frequencies of the m radio frequency channels enabled by the acousto-optic tunable filter according to the m wavelengths in the required spectrum and the correspondence between the radio frequency frequency of the acousto-optic tunable filter and the output wavelength;

[0056] The output wavelength and RF intensity of each RF channel are determined based on the RF frequency and RF intensity of each RF channel enabled by the acousto-optic tunable filter.

[0057] The seed light outputted from the second output end of the optical fiber coupler 11 is injected into the optical fiber amplifier 3 to obtain a high-power fundamental frequency light output with customizable spectrum.

[0058] The fundamental frequency light output by the optical fiber amplifier 3 is injected into the chirped polarization period lithium niobate waveguide 4, where nonlinear frequency conversion occurs, and a multi-wavelength visible light laser output with customizable spectrum is obtained. Figure 4 As shown, the mixing and frequency doubling process will make the frequency f i and f j The fundamental frequency light is also generated with a frequency of 2f i and 2f j The doubled frequency light and the frequency f i +f j The sum frequency light can be used to expand the number of wavelengths.

[0059] The wavelength division multiplexer 5 separates the fundamental frequency light from the visible light. The fundamental frequency light is output from the fundamental frequency light output terminal 6 , and the visible light is output from the visible light output terminal 7 .

[0060] Matters not covered by the present invention are known technologies.

[0061] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, 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.

[0062] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-wavelength visible light source that utilizes a hybrid nonlinear process to enhance spectral performance, characterized in that: It includes a seed source with customizable spectrum, a fiber amplifier, a chirped polarization period lithium niobate waveguide, a wavelength division multiplexer, a fundamental frequency light output end, and a visible light output end; The spectrally customizable seed source outputs seed light of a required spectrum; the spectrally customizable seed source is connected to the input end of the optical fiber amplifier, the output end of the optical fiber amplifier is connected to the input end of the chirped polarization period lithium niobate waveguide, the output end of the chirped polarization period lithium niobate waveguide is connected to the input end of the wavelength division multiplexer, one output end of the wavelength division multiplexer is connected to the baseband light output end, and the other output end of the wavelength division multiplexer is connected to the visible light output end.

2. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 1, characterized in that: A spectrally customizable seed source outputs seed light of a desired spectrum; the seed light output by the spectrally customizable seed source is injected into an optical fiber amplifier to obtain a high-power fundamental frequency light output; the fundamental frequency light output by the optical fiber amplifier is injected into a chirped polarization periodic lithium niobate waveguide, and nonlinear frequency conversion occurs to obtain a spectrally customizable multi-wavelength visible light output; a wavelength division multiplexer separates the fundamental frequency light from the visible light, and the fundamental frequency light is output from the fundamental frequency light output end, and the visible light is output from the visible light output end.

3. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 2, characterized in that: The wavelength range corresponding to the polarization period of the chirped polarization period lithium niobate waveguide needs to cover the required spectral range.

4. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 2 or 3, characterized in that: The spectrally customizable seed source comprises a superfluorescent fiber light source and an acousto-optic tunable filter. The superfluorescent fiber light source is connected to the input end of the acousto-optic tunable filter, and the output end of the acousto-optic tunable filter is connected to the input end of the fiber amplifier.

5. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 4, characterized in that: A superfluorescent fiber light source provides initial seed light, and the transmission spectrum of the initial seed light is customized through an acousto-optic tunable filter to achieve customized output of the spectrum of the superfluorescent seed source, including: first determining the required spectrum of the superfluorescent seed source, and then setting the number of radio frequency channels and the radio frequency intensity of the acousto-optic tunable filter according to the required spectrum of the superfluorescent seed source; the initial seed light achieves customized output of the spectrum of the superfluorescent seed source through the acousto-optic tunable filter.

6. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 5, characterized in that: The number of radio frequency channels and radio frequency intensity of the acousto-optic tunable filter are set according to the spectrum of the required superfluorescence seed source, and the method includes: Assume that the AOTF has a total of n available RF channels; According to the wavelength number m of the spectrum of the required superfluorescence seed source, the number m of radio frequency channels of the acousto-optic tunable filter is set, where m is less than or equal to n; Determine the radio frequency frequencies of the m radio frequency channels enabled by the acousto-optic tunable filter according to the m wavelengths in the spectrum of the required superfluorescence seed source and the correspondence between the radio frequency of the acousto-optic tunable filter and the output wavelength; The output wavelength and RF intensity of each RF channel are determined based on the RF frequency and RF intensity of each RF channel enabled by the acousto-optic tunable filter.

7. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 2 or 3, characterized in that: The spectrally customizable seed sources include acousto-optic tunable filters, semiconductor lasers, (N+1)×1 fiber pump / signal combiners, ytterbium-doped fibers, fiber couplers, and fiber isolators; There are N semiconductor lasers, where N is greater than or equal to 1; the fiber coupler is a fiber coupler capable of splitting an input light beam into two output light beams according to a certain splitting ratio; The output pigtails of N semiconductor lasers are connected to N pump arms of (N+1)×1 optical fiber pump / signal combiner, the combining end of the optical fiber pump / signal combiner is connected to the input end of the ytterbium-doped optical fiber, the output end of the ytterbium-doped optical fiber is connected to the input end of the optical fiber coupler, the optical fiber coupler has two output ends, the first output end of the optical fiber coupler is connected to an acousto-optic tunable filter, the acousto-optic tunable filter is connected to an optical fiber isolator and then connected to the signal input arm of the (N+1)×1 optical fiber pump / signal combiner; the second output end of the optical fiber coupler is connected to the input end of the optical fiber amplifier; The (N+1)×1 fiber pump / signal combiner, ytterbium-doped fiber, fiber coupler, acousto-optic tunable filter, and fiber isolator are connected into a ring cavity. The acousto-optic tunable filter provides laser gain feedback in the ring cavity, and the fiber isolator is used to block the reverse traveling wave.

8. The multi-wavelength visible light source for improving spectral performance by using a hybrid nonlinear process according to claim 7, characterized in that: The lasers output by N semiconductor lasers are coupled into the ytterbium-doped fiber through an (N+1)×1 fiber pump / signal combiner to excite a wide-spectrum ASE light, which is split by the ytterbium-doped fiber through a fiber coupler, and a small portion of the laser is separated and enters the acousto-optic tunable filter through the first output end of the fiber coupler; the number of radio frequency channels and the radio frequency intensity of the acousto-optic tunable filter are set according to the required spectrum to achieve the customizable output of the seed source output seed laser spectrum with customizable spectrum; the acousto-optic tunable filter outputs the laser with the required spectrum shape, and then passes through the fiber isolator and is coupled into the ytterbium-doped fiber by the fiber pump / signal combiner to provide laser gain feedback, so that the laser with the required spectrum is further enhanced to form laser oscillation, which is output from the second output end of the fiber coupler.

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