A dual-resonator dual-optical-frequency comb light source based on dual phase shifters

Abstract

The application discloses a single-resonant-cavity double-optical-frequency comb light source based on a double phase shifter, which comprises a polarization maintaining fiber coupler, a polarization maintaining gain fiber, a double phase shifter and an output device connected in sequence through a polarization maintaining fiber, wherein the polarization maintaining fiber coupler is used for outputting optical signals input through different input ends according to requirements through corresponding output ends; the polarization maintaining gain fiber is used for amplifying optical signals excited by pump laser output through the polarization maintaining fiber coupler; the double phase shifter is used for simultaneously constructing nonlinear amplification loop mirrors on the fast and slow axes of the polarization maintaining fiber, so as to generate double optical frequency combs of orthogonal polarizations in a single resonant cavity in a polarization multiplexing mode; and the output device is used for outputting the double optical frequency combs. Therefore, the double phase shifter can be used for realizing wide-range flexible adjustment of a repetition frequency difference of the double optical frequency combs.

Description

Technical Field

[0001] This invention relates to a single-cavity dual-optical frequency comb light source based on a dual phase shifter, and belongs to the field of optical technology. Background Technology

[0002] The advent of optical frequency combs has revolutionized the field of optical precision metrology. Due to their advantages such as multi-band coverage, wide spectral width, independent longitudinal mode resolution, and ultra-high frequency stability, they have been applied in time reference and time-frequency transmission, distance measurement, spectroscopy, and other fields. Dual optical frequency comb technology offers advantages such as wide spectral width, high resolution, and high speed. To obtain phase-stable, longitudinal-mode-resolved interference signals, good mutual coherence between the two optical frequency combs must be ensured.

[0003] Dual optical frequency comb technology utilizes two optical frequency combs with a small repetition frequency difference for measurement. One optical frequency comb serves as the signal light, probing for information such as distance or spectrum, while the other serves as the local oscillator, asynchronously sampling the signal light. By using multiheterodyne interference, the optical frequency domain containing the measured information is mapped to the radio frequency domain. The phase information in the optical frequency domain can be calculated through low-frequency detection. Therefore, dual optical frequency comb technology provides a powerful tool for dynamic, high-precision measurement and represents a future direction for high-precision measurement. To obtain a phase-stable, longitudinally mode-resolved interference signal, both optical frequency combs must have narrow optical longitudinal mode linewidths, or sufficiently good mutual coherence; this is the core of dual optical frequency comb technology. Early dual optical frequency comb technologies used a continuous laser locked to an ultrastable cavity to beat the optical frequency comb, employing a high-feedback-bandwidth actuator to tightly lock the beat signal, resulting in an optical frequency comb light source with extremely high optical frequency stability. Another method is post-processing correction, which directly compensates for the noise of the interference signal after obtaining the relative fluctuations between the two optical frequency combs, and can use analog signal processing or digital signal correction. Both of these technologies require relatively complex feedback systems or signal processing modules to suppress noise, and are quite expensive, which limits the further application of dual optical frequency comb technology in the field of precision metrology.

[0004] Unlike the two active locking techniques mentioned above, the single-cavity dual-comb technique generates two optical frequency combs based on a single optical resonant cavity. Since the two optical frequency combs share a single resonant cavity, common-mode noise between them can be passively suppressed, naturally resulting in better mutual coherence. The single-cavity dual-comb technique typically reuses a specific characteristic of the resonant cavity to obtain two optical frequency combs, such as different propagation directions, different operating wavelengths, and different pulse polarizations of a ring resonant cavity. However, methods for generating two optical frequency combs based on the single-cavity dual-comb technique usually face the problem of small repetition frequency difference and a small tuning range, making them inconvenient to use. Therefore, designing novel, long-term stable single-cavity dual-comb light sources with flexible repetition frequency difference tuning remains a research focus. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, in response to the above-mentioned problems, the object of the present invention is to provide a single-cavity dual-optical frequency comb light source based on a dual-phase shifter capable of generating a certain repetition frequency difference with a wide range of flexible adjustment of the repetition frequency difference.

[0006] To achieve the purpose of this invention, the technical solution adopted is as follows:

[0007] This invention provides a single-cavity dual-optical frequency comb light source based on a dual-phase shifter. The light source includes:

[0008] Pump source, used to generate pump laser;

[0009] The laser resonant cavity includes a polarization-maintaining fiber coupler, a polarization-maintaining gain fiber, a two-phase shifter, and an output device, which are connected sequentially via polarization-maintaining fibers.

[0010] The polarization-maintaining fiber coupler is used to output optical signals input from different input terminals through corresponding output terminals as required.

[0011] The polarization-maintaining gain fiber is used to amplify the optical signal excited by the pump laser output from the polarization-maintaining fiber coupler.

[0012] The dual phase shifter is used to simultaneously construct a nonlinear amplification loop mirror on the fast and slow axes of the polarization-maintaining fiber, thereby generating orthogonally polarized dual optical frequency combs in a single resonant cavity in a polarization multiplexing manner.

[0013] The output device is used to output a dual optical frequency comb.

[0014] In a preferred embodiment, the device further includes a polarization-maintaining fiber wavelength division multiplexer for inputting the pump laser into the polarization-maintaining fiber coupler. The polarization-maintaining fiber wavelength division multiplexer is provided with a first reflecting end and a second reflecting end, the first reflecting end being connected to the pump laser and the second reflecting end being connected to the polarization-maintaining fiber coupler.

[0015] In a preferred embodiment, the polarization-maintaining fiber coupler is provided with a first port, a second port, a third port, and a fourth port, and the dual phase shifter is provided with a port one and a port two; the first port is connected to the second reflector, the second port is connected to the port one through the polarization-maintaining gain fiber, the port two is connected to the third port, and the fourth port is connected to the output device.

[0016] In a preferred embodiment, the dual-phase shifter includes a first polarization-maintaining fiber collimator, a second polarization-maintaining fiber collimator, a polarization beam splitter, a first Faraday rotator, a second Faraday rotator, a first waveplate, a second waveplate, a first mirror, and a second mirror. Light transmitted along the slow axis of the first polarization-maintaining fiber collimator is transmitted through the polarization beam splitter and then reflected sequentially by the first Faraday rotator, the first waveplate, and the first mirror. The reflected light returns along the original optical path, passes through the first waveplate and the first Faraday rotator again, is reflected by the polarization beam splitter, and is then received by the slow axis of the second polarization-maintaining fiber collimator. Light transmitted along the fast axis of the first polarization-maintaining fiber collimator is reflected by the polarization beam splitter and then reflected sequentially by the second Faraday rotator, the second waveplate, and the second mirror. The reflected light passes sequentially through the second waveplate and the second Faraday rotator and is transmitted through the polarization beam splitter. The light transmitted through the beam splitter is then received by the fast axis of the second polarization-maintaining fiber collimator.

[0017] The dual-phase shifter is used to simultaneously construct nonlinear amplification loop mirrors on the fast and slow axes of the polarization-maintaining fiber. The positions of the first and second mirrors determine the repetition frequencies of the two optical frequency combs, respectively. Moving the corresponding mirrors along the direction of light propagation can independently adjust the repetition frequencies of their respective optical frequency combs.

[0018] In a preferred embodiment, the slow axis or fast axis of the first polarization-maintaining fiber collimator is rotated 90 degrees relative to the slow axis or fast axis of the second polarization-maintaining fiber collimator to ensure that light always propagates along the slow axis or fast axis.

[0019] In a preferred embodiment, the first and second Faraday rotators rotate the incident ray-polarized light by 45 degrees in the same direction.

[0020] In a preferred embodiment, the fast axes of the first waveplate and the second waveplate are at 45° to the horizontal plane, and the fast axes of the first waveplate and the second waveplate are spatially perpendicular to each other; or;

[0021] The slow axes of the first and second waveplates are at 45° to the horizontal plane, and the slow axes of the first and second waveplates are spatially perpendicular to each other.

[0022] In a preferred embodiment, the polarization-maintaining gain fiber is an erbium-doped polarization-maintaining fiber or a ytterbium-doped polarization-maintaining fiber.

[0023] In a preferred embodiment, the output device is a polarization-maintaining fiber semi-reflective lens, which serves as the end mirror of the laser resonant cavity and outputs dual optical frequency combs.

[0024] In a preferred embodiment, the output device further includes a grating device for dispersive compensation of the laser resonant cavity.

[0025] This invention, by adopting the above technical solutions, has the following characteristics: The single-cavity dual-optical frequency comb light source based on a dual-phase shifter provided by this invention uses a polarization-maintaining fiber coupler, a polarization-maintaining gain fiber, a dual-phase shifter, and output devices to form a laser resonant cavity, generating and outputting an optical frequency comb. By simultaneously constructing nonlinear amplification loop mirrors along the fast and slow axes of the polarization-maintaining fibers of each device in the laser resonant cavity through the dual-phase shifter, orthogonal polarization dual-optical frequency comb output is achieved in a single polarization-maintaining laser resonant cavity using polarization multiplexing. Furthermore, it exhibits greater long-term stability compared to the mode-locking method using a solid saturable absorber. The dual-phase shifter of this invention allows for a wide range of flexible adjustment of the repetition frequency difference of the dual optical frequency comb. The adjustment range of the repetition frequency difference is not limited by the mode-locking mechanism but depends on the collimation and coupling degree of the polarization-maintaining fiber collimator. In summary, this invention can be widely applied in the fabrication of dual optical frequency combs. Attached Figure Description

[0026] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0027] Figure 1 This is a schematic diagram of a single-cavity dual-optical frequency comb structure based on a dual phase shifter according to an embodiment of the present invention.

[0028] Figure 2 This is the output performance curve of an embodiment of the present invention. Detailed Implementation

[0029] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0030] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0031] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0032] The method of generating dual optical frequency combs using single-cavity dual-comb technology typically faces problems such as small repetition frequency difference and limited tuning range, making it inconvenient to use. This invention provides a single-cavity dual optical frequency comb light source based on a dual-phase shifter. This light source includes: a pump source for generating pump laser; a laser resonant cavity including a polarization-maintaining fiber coupler, a polarization-maintaining gain fiber, a dual-phase shifter, and an output device connected sequentially via polarization-maintaining fibers. Specifically: the polarization-maintaining fiber coupler is used to output optical signals input from different input ends through corresponding output ends as required; the polarization-maintaining gain fiber is used to amplify the optical signal excited by the pump laser output from the polarization-maintaining fiber coupler; the dual-phase shifter is used to simultaneously construct a nonlinear amplification loop mirror along the fast and slow axes of the polarization-maintaining fiber, generating orthogonally polarized dual optical frequency combs in a single resonant cavity through polarization multiplexing; and the output device is used to output the dual optical frequency combs. Therefore, the dual-phase shifter of this invention can be used to achieve a wide range of flexible adjustment of the repetition frequency difference of the dual optical frequency combs.

[0033] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0034] like Figure 1As shown, the single-cavity dual-optical frequency comb light source based on dual phase shifters provided in this embodiment is implemented based on a fiber mode-locked laser, including a pump source 1, a polarization-maintaining fiber wavelength division multiplexer 2, and a laser resonant cavity. The laser resonant cavity includes a polarization-maintaining fiber coupler 3, a polarization-maintaining gain fiber 4, a dual phase shifter 5, and an output device 6 connected in sequence through polarization-maintaining fibers.

[0035] Pump source 1 is used to generate the pump laser. The pump laser is emitted through a standard polarization-maintaining fiber to a polarization-maintaining fiber wavelength division multiplexer 2. Polarization-maintaining fiber wavelength division multiplexer 2 uses optical wavelength multiplexing technology to allow light of different wavelengths to be transmitted simultaneously within the device, and is used to input the pump laser generated by pump source 1 into the laser resonant cavity. The laser emitted from polarization-maintaining fiber wavelength division multiplexer 2 is emitted through a polarization-maintaining fiber coupler 3 and a polarization-maintaining gain fiber 4 to a dual phase shifter 5. The polarization-maintaining fiber coupler 3 has one or more input or output points, and the optical signal input from the input point can be output through the corresponding output point at different ratios. The polarization-maintaining gain fiber 4 is a polarization-maintaining single-mode fiber doped with rare-earth gain ions. The doped rare-earth ions, after being excited by the pump laser, can be used to amplify the optical signal. The dual phase shifter 5 is used to simultaneously construct nonlinear amplification loop mirrors on the fast and slow axes of the polarization-maintaining fibers of each device in the laser resonant cavity, generating orthogonally polarized dual optical frequency combs in a single resonant cavity through polarization multiplexing. The output device 6 is connected to the dual phase shifter 5 via the polarization-maintaining fiber coupler 3 for outputting dual optical frequency combs.

[0036] In a preferred embodiment of the present invention, the polarization-maintaining fiber wavelength division multiplexer 2 is provided with a reflecting end 2a and a reflecting end 2b. The polarization-maintaining fiber coupler 3 is provided with ports 3a, 3b, 3c, and 3d. The dual phase shifter 5 is provided with ports 5a and 5b. The pump source 1 is connected to the reflecting end 2a of the polarization-maintaining fiber wavelength division multiplexer 2. The pump light is reflected to the reflecting end 2b and then connected to port 5a of the dual phase shifter 5 via ports 3a and 3b of the polarization-maintaining fiber coupler 3 and polarization-maintaining gain fiber 4. Port 5b of the dual phase shifter 5 is connected to port 3c of the polarization-maintaining fiber coupler 3. Port 3d of the polarization-maintaining fiber coupler 3 is connected to the output device 6.

[0037] Furthermore, the two ends of the polarization-maintaining gain fiber 4 are fused to port 3b of the polarization-maintaining fiber coupler 3 and port 5a of the dual phase shifter 5, respectively, and port 5b of the dual phase shifter 5 is fused to port 3c of the polarization-maintaining fiber coupler 3.

[0038] In a preferred embodiment of the present invention, the dual phase shifter 5 includes a first polarization-maintaining fiber collimator 51, a second polarization-maintaining fiber collimator 56, a polarization beam splitter 52, a first Faraday rotator 53, a second Faraday rotator 57, a first 1 / 8 waveplate 54, a second 1 / 8 waveplate 58, a first reflector 55, and a second reflector 59.

[0039] The light transmitted on the slow axis of the first polarization-maintaining fiber collimator 51 is transmitted through the polarization beam splitter 52 and then reflected sequentially by the first Faraday rotator 53, the first 1 / 8 wave plate 54 and the first reflector 55. The reflected light returns along the original optical path and passes through the first 1 / 8 wave plate 54 and the first Faraday rotator 53 again. After being reflected by the polarization beam splitter 52, it is received by the slow axis of the second polarization-maintaining fiber collimator 56.

[0040] The light transmitted on the fast axis of the first polarization-maintaining fiber collimator 51 is reflected by the polarization beam splitter 52 and then sequentially reflected by the second Faraday rotator 57, the second octave plate 58, and the second mirror 59. The reflected light is then transmitted through the second octave plate 58 and the second Faraday rotator 57 and then transmitted by the polarization beam splitter 52. The light transmitted by the beam splitter 52 is received by the fast axis of the second polarization-maintaining fiber collimator 56.

[0041] The dual phase shifter 5 is used to simultaneously construct nonlinear amplification loop mirrors on the fast and slow axes of the polarization-maintaining fibers of each device in the laser resonant cavity. The dual phase shifter 5 can be used for flexible tuning of the repetition frequency difference of the two optical frequency combs. The positions of the first mirror 55 and the second mirror 59 in the dual phase shifter 5 determine the repetition frequency of the two optical frequency combs. Moving the corresponding mirrors along the direction of light propagation can independently adjust the repetition frequency of each optical frequency comb. Therefore, by changing the relative positions of the first mirror 55 and the second mirror 59 in the dual phase shifter 5, the repetition frequency difference can be tuned from zero to almost any value. The maximum tuning range depends on the degree of coupling between the first polarization-maintaining fiber collimator 51 and the second polarization-maintaining fiber collimator 56 and the first mirror 55 and the second mirror 59.

[0042] Furthermore, the slow axis (fast axis) of the first polarization-maintaining fiber collimator 51 is rotated 90 degrees relative to the slow axis (fast axis) of the second polarization-maintaining fiber collimator 56 to ensure that light always propagates along the slow axis (fast axis). The slow axis of the first polarization-maintaining fiber collimator 51 can be perpendicular to the paper or parallel to the paper, which is not limited here; however, after the direction of the slow axis of the polarization-maintaining fiber collimator 51 is determined, the slow axis of the polarization-maintaining fiber collimator 52 needs to be rotated 90 degrees relative to the polarization-maintaining fiber collimator 51. That is, if the slow axis of 51 is perpendicular to the paper, then the slow axis of 52 is parallel to the paper, and if the slow axis of 51 is parallel to the paper, then the slow axis of 52 is perpendicular to the paper.

[0043] Furthermore, the first Faraday rotator 53 and the second Faraday rotator 57 rotate the incident polarized light by 45 degrees in the same direction.

[0044] Furthermore, the first 1 / 8 waveplate 54 and the second 1 / 8 waveplate 58 are used to introduce a linear phase delay in the laser resonant cavity, thereby changing the transmittance curve of the optical signal in the resonant cavity to generate a mode-locked pulse. There are many possible transmittance curves that can achieve mode-locking, corresponding to different waveplate delay amounts. These can be other waveplate delay amounts that are easy for pulse mode-locking, such as a 1 / 6 waveplate, etc., but are not limited to this. In addition, the fast axes of the first 1 / 8 waveplate 54 and the second 1 / 8 waveplate 58 are at 45° to the horizontal plane, and the fast axes of the first 1 / 8 waveplate 54 and the second 1 / 8 waveplate 58 are spatially perpendicular to each other; or, the slow axes of the first 1 / 8 waveplate 54 and the second 1 / 8 waveplate 58 are at 45° to the horizontal plane, and the first 1 / 8 waveplate 54 and the second 1 / 8 waveplate 58 are spatially perpendicular to each other.

[0045] In a preferred embodiment of the present invention, the pump source 1 can be a semiconductor laser. The polarization-maintaining fiber wavelength division multiplexer 2 connected to the semiconductor laser 1 can be fused into the laser resonant cavity, that is, located at any point on the polarization-maintaining fiber coupler port 3b or 3c, or the polarization-maintaining gain fiber 4, or the dual phase shifter port 5a or 5b, for pumping the gain medium of the laser resonant cavity, and the position is not limited.

[0046] In a preferred embodiment of the present invention, the polarization-maintaining gain fiber 4 can be an erbium-doped polarization-maintaining fiber, a ytterbium-doped polarization-maintaining fiber, or other rare-earth ion-doped polarization-maintaining gain fiber. Different working media can be used to realize the laser resonator.

[0047] In a preferred embodiment of the present invention, the standard polarization-maintaining fiber is a single-mode fiber with a built-in stress bar. The built-in stress bar generates strong birefringence to isolate the polarization state of the light transmitted in the fiber from the inhomogeneities generated during the fiber manufacturing process or the interference of external environmental disturbances.

[0048] In a preferred embodiment of the present invention, the output device 6 may be a polarization-maintaining fiber semi-reflective lens, which is used to reflect part of the optical signal back to the nonlinear amplification loop reflector for resonance to generate laser. The semi-transparent and semi-reflective characteristics make the polarization-maintaining fiber semi-reflective lens both the end mirror of the laser resonant cavity and the output of the laser resonant cavity. That is, the polarization-maintaining fiber semi-reflective lens serves as the end mirror of the optical resonant cavity and outputs dual optical frequency combs.

[0049] Furthermore, output device 6 also includes a grating device for dispersion compensation of the laser resonator. The grating device can be a chirped fiber Bragg grating. A chirped fiber Bragg grating introduces an aperiodic refractive index distribution in a single-mode fiber, which provides a certain reflectivity for a specific spectral bandwidth. At the same time, due to the aperiodic refractive index distribution, group delay dispersion can be introduced. The design of the aperiodic refractive index distribution makes it suitable for use as dispersion compensation for the laser resonator. Alternatively, a spatial device grating or a polarization-maintaining dispersion compensation fiber can also be used for dispersion compensation of the laser resonator to achieve the same mode-locking effect. No limitation is made here.

[0050] In summary, the single-cavity dual-optical frequency comb light source based on a dual-phase shifter of the present invention constitutes a laser resonant cavity through a polarization-maintaining fiber coupler 3, a polarization-maintaining gain fiber 4, a dual-phase shifter 5, and an output device 6. Nonlinear amplification loop mirrors are constructed on the fast and slow axes of the polarization-maintaining fibers of each device in the laser resonant cavity via the dual-phase shifter 5, thereby simultaneously generating orthogonally polarized dual optical frequency combs in a single laser resonant cavity. The repetition frequency difference can be flexibly tuned by adjusting the relative positions of the mirrors within the dual-phase shifter 5. The laser resonant cavity based on the dual-phase shifter can be used to realize a dual optical frequency comb light source with a simplified structure, good mutual coherence, and flexible repetition frequency difference tuning.

[0051] like Figure 2 As shown, the output light is an orthogonally polarized dual optical frequency comb with a certain repetition frequency difference; after polarization beam splitting, two optical frequency combs can be obtained separately; it can be seen that the output spectra are basically overlapping and the spectrum has a wide width; the output spectrum has no obvious modulation under full scan width, indicating that the dual optical frequency comb light source is working in single-pulse mode-locked state and can be used for optical precision measurement applications; the fundamental frequency spectrum is about 60dB and the crosstalk suppression to the other optical frequency comb can reach more than 30dB.

[0052] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In the description of this specification, the terms "a preferred embodiment," "furthermore," "specifically," "in this embodiment," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single-cavity dual-optical frequency comb light source based on a dual phase shifter, characterized in that, The light source includes: Pump source, used to generate pump laser; A laser resonant cavity includes a polarization-maintaining fiber coupler, a polarization-maintaining gain fiber, a dual phase shifter, and an output device, which are connected in sequence via polarization-maintaining fibers. A polarization-maintaining fiber wavelength division multiplexer is used to input the pump laser into the polarization-maintaining fiber coupler. The polarization-maintaining fiber wavelength division multiplexer is provided with a first reflection end and a second reflection end. The first reflection end is connected to the pump laser, and the second reflection end is connected to the polarization-maintaining fiber coupler, wherein: The polarization-maintaining fiber coupler is used to output optical signals input from different input terminals through corresponding output terminals as required; the polarization-maintaining fiber coupler is provided with a first port, a second port, a third port and a fourth port, and the dual phase shifter is provided with a port one and a port two; the first port is connected to the second reflection terminal, the second port is connected to the port one through the polarization-maintaining gain fiber, the port two is connected to the third port, and the fourth port is connected to the output device; The polarization-maintaining gain fiber is used to amplify the optical signal excited by the pump laser output from the polarization-maintaining fiber coupler. The dual-phase shifter is used to simultaneously construct a nonlinear amplification loop mirror along the fast and slow axes of the polarization-maintaining fiber, generating orthogonally polarized dual optical frequency combs in a single resonant cavity through polarization multiplexing. The dual-phase shifter includes a first polarization-maintaining fiber collimator, a second polarization-maintaining fiber collimator, a polarization beam splitter, a first Faraday rotator, a second Faraday rotator, a first waveplate, a second waveplate, a first mirror, and a second mirror. Light transmitted along the slow axis of the first polarization-maintaining fiber collimator is transmitted through the polarization beam splitter and then sequentially passes through the first Faraday rotator, the first waveplate, and the second mirror. A mirror reflects the light, which returns along the original optical path and is reflected again by the first waveplate and the first Faraday rotator. The reflected light is then reflected by the polarization beam splitter and received by the slow axis of the second polarization-maintaining fiber collimator. The light transmitted on the fast axis of the first polarization-maintaining fiber collimator is reflected by the polarization beam splitter and then sequentially reflected by the second Faraday rotator, the second waveplate, and the second mirror. The reflected light is then transmitted through the second waveplate and the second Faraday rotator and then transmitted by the polarization beam splitter. The light transmitted through the beam splitter is received by the fast axis of the second polarization-maintaining fiber collimator. The dual-phase shifter is used to simultaneously construct nonlinear amplification loop mirrors on the fast and slow axes of the polarization-maintaining fiber. The positions of the first and second mirrors determine the repetition frequencies of the two optical frequency combs, respectively. Moving the corresponding mirrors along the direction of light propagation can independently adjust the repetition frequencies of their respective optical frequency combs. The output device is used to output dual optical frequency combs. The output device adopts a polarization-maintaining fiber semi-reflective lens, which serves as the end mirror of the laser resonant cavity and outputs dual optical frequency combs. The output device also includes a grating device for dispersion compensation of the laser resonant cavity.

2. The single-cavity dual-optical frequency comb light source based on a dual phase shifter according to claim 1, characterized in that, The slow axis or fast axis of the first polarization-maintaining fiber collimator is rotated 90 degrees relative to the slow axis or fast axis of the second polarization-maintaining fiber collimator to ensure that light always propagates along the slow axis or fast axis.

3. The single-cavity dual-optical frequency comb light source based on a dual phase shifter according to claim 1, characterized in that, The first and second Faraday rotators rotate the incident polarized light by 45 degrees in the same direction.

4. The single-cavity dual-optical frequency comb light source based on a dual phase shifter according to claim 1, characterized in that, The fast axes of the first and second waveplates are at 45° to the horizontal plane, and the fast axes of the first and second waveplates are spatially perpendicular to each other; or; The slow axes of the first and second waveplates are at 45° to the horizontal plane, and the slow axes of the first and second waveplates are spatially perpendicular to each other.

5. The single-cavity dual-optical frequency comb light source based on a dual phase shifter according to claim 1, characterized in that, The polarization-maintaining gain fiber is either erbium-doped polarization-maintaining fiber or ytterbium-doped polarization-maintaining fiber.

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