Passive laser gyroscope based on four-frequency differential motion and measuring method thereof

Abstract

The invention discloses a passive laser gyroscope based on four-frequency differential motion and a measurement method thereof, and belongs to the technical field of laser gyroscopes. A laser beam splitting module outputs first laser and second laser; the first light beam locking module and the second light beam locking module carry out frequency locking, and inject the first path of laser into the annular resonant cavity module in the anticlockwise direction and inject the second path of laser into the annular resonant cavity module in the clockwise direction; the annular resonant cavity module carries out reciprocal frequency splitting and non-reciprocal frequency splitting to form clockwise left-handed polarized light, clockwise right-handed polarized light, anticlockwise left-handed polarized light and anticlockwise right-handed polarized light with different frequencies, so that a first path of optical signal and a second path of optical signal are formed; and the signal detection module performs signal conversion and differential processing based on the signal detection module to obtain the angular velocity of the resonant cavity. According to the passive laser gyroscope based on the four-frequency differential motion and the measurement method thereof disclosed by the invention, noise related to a gain medium is eliminated, and the stability of high-precision angular velocity measurement is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of laser gyroscope technology, and in particular to a passive laser gyroscope based on four-frequency differential and its measurement method. Background Technology

[0002] Laser gyroscopes, as optical inertial sensors based on the Sagnac effect, are core components of modern high-precision inertial navigation systems. However, their inherent latch-up effect necessitates frequency offsetting to avoid the latch-up zone, employing techniques such as mechanical jitter frequency offsetting and magneto-optical alternating frequency offsetting. Among these, the four-frequency differential laser gyroscope utilizes the Faraday magneto-optical effect to achieve all-solid-state optical frequency offsetting. Through the combined action of non-reciprocal and reciprocal optical rotators within the cavity, four circularly polarized lights of different frequencies are formed. Finally, a differential measurement method is employed, effectively eliminating latch-up, suppressing common-mode noise, and doubling the sensitivity. It is foreseeable that the four-frequency differential laser gyroscope represents a significant future development direction for high-precision laser gyroscopes. However, existing high-performance four-frequency differential laser gyroscopes generally employ active laser gyroscopes, relying on the discharge of the cavity gain medium to generate laser light. Therefore, employing active laser gyroscopes introduces inherent physical limitations: First, the Langmuir current effect induced by the discharge process generates significant null drift and noise; second, mode competition and discharge instability in the gain medium introduce additional noise; and third, the discharge components such as cathodes and anodes have lifespan and reliability issues. These inherent defects caused by the active characteristics within the cavity significantly limit the performance improvement of traditional four-frequency differential technology.

[0003] To overcome the limitations of active laser gyroscopes, a four-frequency differential passive laser gyroscope can be designed by utilizing the passive characteristics of the cavity. Because it is locked by an external ultra-stable laser, it fundamentally eliminates noise sources such as Langmuir flow, mode competition, and discharge noise, theoretically possessing enormous potential for achieving ultra-high performance. However, applying four-frequency differential technology to passive laser gyroscopes presents several new challenges: First, using multiple independent lasers to lock four frequencies results in an extremely complex and costly system, making synchronous stability difficult and introducing more noise. Second, using the traditional discrete optical rotators and mirrors leads to severe backscattering due to the perpendicular incidence of the laser on the surface of the optical rotators, introducing measurement errors. Furthermore, the introduction of multiple components increases cavity losses and packaging difficulty, undermining the high Q-factor (quality factor) advantage of the passive cavity. Therefore, given the limitations of the performance of active four-frequency differential schemes and the lack of efficient and stable implementation methods for passive schemes, there is an urgent need to provide a laser gyroscope that can solve the inherent defects of existing technologies due to the active characteristics of the cavity, while also achieving synchronous stability. Summary of the Invention

[0004] This invention provides a passive laser gyroscope based on four-frequency differential and its measurement method, which can solve the technical problems of gain medium-related noise sources such as mode competition and discharge noise caused by active laser gyroscopes in the prior art, and effectively improve the stability of laser gyroscopes in high-precision angular velocity measurement.

[0005] This invention provides a passive laser gyroscope based on four-frequency differential, comprising a laser beam splitting module, a first beam locking module, a second beam locking module, a ring resonant cavity module, and a signal detection module. The ring resonant cavity module contains no gain medium. The laser beam splitting module is used to output the original laser and split the original laser into a first laser and a second laser. The first beam locking module is used to lock the frequency of the first laser, obtain the first laser path, and inject the first laser path into the annular resonant cavity module in a counterclockwise direction; The second beam locking module is used to lock the frequency of the second laser, obtain the second laser beam, and inject the second laser beam into the annular resonant cavity module in a clockwise direction; The ring resonant cavity module is used to perform reciprocal frequency splitting and non-reciprocal frequency splitting on the first and second laser beams to form clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light, and counterclockwise right-handed polarized light of different frequencies. Then, the clockwise right-handed polarized light and the counterclockwise right-handed polarized light are coupled to form a first optical signal and output to the signal detection module. The counterclockwise left-handed polarized light and the clockwise left-handed polarized light are coupled to form a second optical signal and output to the signal detection module. The signal detection module is used to perform signal conversion and differential processing based on the first optical signal and the second optical signal to obtain the resonant cavity angular velocity.

[0006] This invention provides a passive laser gyroscope based on four-frequency differential. It achieves laser injection and locking outside the ring resonant cavity module through a laser beam splitting module, fundamentally eliminating the noise source caused by the gain medium in active gyroscopes. This solves the technical problems of gain medium-related noise sources such as mode competition and discharge noise in existing active laser gyroscopes, effectively improving the stability of the laser gyroscope for high-precision angular velocity measurement. Simultaneously, the laser beam splitting module outputs a single raw laser beam, which is then split and frequency-locked before being input into the ring resonant cavity module, where reciprocal and non-reciprocal frequency splitting is performed. By generating four-frequency optical signals, the inherent latch-up effect of laser gyroscopes is avoided, eliminating the need for complex mechanical jitter and frequency shifting mechanisms for subsequent detection and measurement. This achieves functional symmetry between the two input optical paths, avoiding the complexity of multi-laser systems and reducing path loss. The signal detection module's conversion and differential processing accurately extract signals proportional to the resonant cavity angular velocity, effectively suppressing common-mode noise and significantly improving measurement accuracy and anti-interference capability. Utilizing the passive characteristics of passive laser gyroscope cavities, a passive laser gyroscope based on four-frequency differential is designed, combining the advantages of simplicity, high stability, low loss, and high accuracy, making it suitable for high-precision inertial navigation systems.

[0007] Furthermore, the laser beam splitting module includes a laser source, a beam splitter, a first reflector, and a second reflector, wherein: The laser source is used to output raw laser light; The beam splitter is used to split the original laser beam into a first-direction laser and a second-direction laser with the same frequency. The first reflector is used to perform path conversion on the laser beam in the first direction to obtain the first laser beam; The second reflector is used to perform path conversion on the laser in the second direction to obtain the second laser.

[0008] In the above scheme, a single laser source is set in the laser beam splitting module, which solves the technical problems of complex device, high cost and difficulty in synchronizing and stabilizing existing systems that use multiple independent lasers. A beam splitter is used to form two laser beams with the same frequency but different directions. Then, a first and a second reflector are used to adjust the optical path and precisely guide the two laser beams after beam splitting to the first and second beam locking modules. This ensures that the subsequent laser can be injected into the ring resonant cavity in the preset direction, reducing the loss and measurement error caused by optical path deviation. At the same time, a symmetrical design is achieved to ensure the functional symmetry of the two laser beams.

[0009] Furthermore, the ring resonant cavity module includes a ring resonant cavity, a first input cavity mirror, a second input cavity mirror, and an output cavity mirror. The ring resonant cavity contains no gain medium, wherein: The first input cavity mirror is used to receive the first laser beam and input it into the annular resonant cavity; The second input cavity mirror is used to receive the second laser beam and input it into the annular resonant cavity; The ring resonant cavity is provided with an optical frequency polarization component, which is used to transmit the first laser and the second laser to the optical frequency polarization component, so that the optical frequency polarization component performs reciprocal frequency splitting and non-reciprocal frequency splitting on the first laser and the second laser to form clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light and counterclockwise right-handed polarized light. The output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module, and to couple the counterclockwise left-handed polarized light and the clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

[0010] In the above scheme, there is no gain medium in the ring resonator, and an optical frequency polarization component is provided to introduce reciprocal frequency splitting and non-reciprocal frequency splitting, so as to convert the externally injected first laser and second laser into four polarized lights of different frequencies. Finally, the first optical signal and the second optical signal carrying beat frequency information are coupled out, providing a pure optical input for the accurate capture of the signal detection module, avoiding signal distortion caused by the mixing of different polarized lights, and successfully avoiding the latch-up effect.

[0011] Furthermore, the output cavity mirror includes a first output cavity mirror and a second output cavity mirror, wherein: The first output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module; The second output cavity mirror is used to couple counterclockwise left-handed polarized light and clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

[0012] In the above scheme, by setting up dual-output cavity mirrors, the physical separation of the two optical signals is achieved, avoiding the signal interference problem that may occur with single-output cavity mirrors. This provides a physical basis for the subsequent differential processing to completely eliminate the non-reciprocal frequency offset, and further improves the stability and accuracy of signal detection.

[0013] Furthermore, the optical polarization component includes discrete reciprocal rotators and non-reciprocal rotators.

[0014] In the above scheme, the optical polarization component uses separate reciprocal rotators and non-reciprocal rotators. The tilt installation of the non-reciprocal rotators can suppress backscattering, reduce measurement errors caused by vertical laser incidence, reduce intracavity loss, ensure the high Q value advantage of the passive cavity, and thus improve the accuracy of subsequent measurements.

[0015] Furthermore, the ring resonant cavity module includes a first input cavity mirror, a second input cavity mirror, a ring resonant cavity, and an output cavity mirror; wherein: The first input cavity mirror is used to receive the first laser beam and input it into the annular resonant cavity; The second input cavity mirror is used to receive the second laser beam and input it into the annular resonant cavity; The annular resonant cavity is equipped with an optical rotation and reflection integrated component, which is used to transmit the first laser and the second laser in an oblique incidence manner to the optical rotation and reflection integrated component, so that the optical rotation and reflection integrated component performs reciprocal optical rotation, non-reciprocal Faraday rotation and reflection on the first laser and the second laser, forming clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light and counterclockwise right-handed polarized light; The output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module, and to couple the counterclockwise left-handed polarized light and the clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

[0016] In the above scheme, the discrete optical polarization components are replaced with an integrated optical rotation and reflection component. The reflection loss and backscattering of the optical surface are suppressed by the laser oblique incidence design, the cavity loss and measurement noise are reduced, the high Q value of the passive cavity is guaranteed, the installation and packaging difficulty of the components in the ring resonant cavity is reduced, the performance fluctuation caused by the assembly deviation of multiple components is avoided, and the mechanical stability and environmental adaptability of the gyroscope are improved.

[0017] Furthermore, the optical rotation and reflection integrated component includes an optical rotation and reflection integrated structure, an antireflection coating, an antireflection coating, and a permanent magnet; wherein: The antireflective film is disposed on the inner surface of the optical rotation and reflection integrated structure; The anti-reflective coating is disposed on the outer surface of the optical rotation and reflection integrated structure in the first direction; The permanent magnet is disposed on the outer side of the optical rotation and reflection integrated structure in the second direction.

[0018] In the above scheme, by designing antireflection and antireflection films in the optical rotation and reflection integrated component, the energy loss of the optical surface of the component is significantly reduced. The antireflection film on the inner side can reduce the reflection loss when the laser is incident, while the antireflection film on the outer side enhances the reflection efficiency and reduces the transmission loss, further ensuring the high Q value of the passive cavity. The permanent magnet provides a stable axial magnetic field for the optical rotation and reflection integrated component, ensuring the consistency and stability of the non-reciprocal Faraday rotation function, making the frequency splitting effect more accurate, avoiding frequency deviation caused by magnetic field instability, and improving the frequency stability of the obtained four-frequency polarized light.

[0019] Furthermore, the signal detection module includes a first photodetector, a second photodetector, and a signal processing unit, wherein: The first photodetector is used to perform signal conversion based on the first optical signal to obtain the first beat frequency signal; The second photodetector is used to perform signal conversion based on the second optical signal to obtain the second beat frequency signal; The signal processing unit is used to perform differential processing on the first beat frequency signal and the second beat frequency signal to obtain the resonant cavity angular velocity.

[0020] In the above scheme, the beat frequency signal is detected by dual photodetectors to achieve independent conversion of the two signals, ensuring signal purity and avoiding cross-interference. The signal processing unit performs differential processing on the first beat frequency signal and the second beat frequency signal to completely eliminate common-mode noise such as non-reciprocal frequency offset, retaining only the difference frequency signal that is proportional to the resonant cavity angular velocity. This makes the measurement results unaffected by common-mode interference, significantly improving the measurement sensitivity and anti-interference capability, and ensuring the accuracy of resonant cavity angular velocity measurement.

[0021] Furthermore, it also includes a frequency-locking loop, wherein: the signal detection module is further configured to acquire a first frequency error signal and a second frequency error signal based on the first optical signal, the second optical signal, and the resonant cavity reference frequency; the frequency-locking loop is configured to: The first frequency error signal and the second frequency error signal are subjected to drive conversion processing to obtain the first frequency adjustment signal and the second frequency adjustment signal; The first frequency adjustment signal is input to the first beam locking module, so that the first beam locking module performs drive frequency adjustment based on the first frequency adjustment signal; The second frequency adjustment signal is input to the second beam locking module, so that the second beam locking module performs drive frequency adjustment based on the second frequency adjustment signal.

[0022] In the above scheme, by adding a frequency-locking loop, the error signal is converted into a frequency adjustment signal, which controls the driving frequency of the first beam-locking module and the second beam-locking module respectively. This allows the injected laser frequency to track the resonant frequency of the ring resonant cavity in real time, effectively offsetting the effects of environmental disturbances and laser source frequency drift, and avoiding beat frequency signal distortion caused by the laser's inability to resonate stably. Through closed-loop feedback control, the stable resonance of the four-frequency polarized light is ensured, further improving the long-term stability and reliability of the passive laser gyroscope measurement.

[0023] This invention provides a passive laser gyroscope based on four-frequency differential. Through a ring resonant cavity design without a gain medium, it completely eliminates the inherent defects of active laser gyroscopes caused by the Langmuir flow effect, mode competition, and discharge noise, thus solving the lifespan and reliability issues of the discharge component. By using discrete or integrated optical frequency-biasing components, it achieves reciprocal and non-reciprocal frequency splitting, successfully avoiding the latch-up effect. Simultaneously, through tilted installation, oblique incidence, and anti-reflection and anti-reflection coatings, it effectively suppresses backscattering, reduces intracavity loss, and ensures the high Q-value advantage of the passive cavity. The design employs a single laser source with a beam splitter, avoiding the complexity of multi-source systems, and ensures the consistency of the two laser sources through functional symmetry design. Through independent detection by dual photodetectors and differential processing by the signal processing unit, common-mode noise is eliminated, doubling the measurement sensitivity. The closed-loop feedback control of the frequency-locking loop further ensures stable matching between the laser frequency and the cavity resonant frequency, improving the long-term stability and anti-interference capability of the passive laser gyroscope. This invention provides a passive laser gyroscope based on four-frequency differential, which has the technical advantages of low noise, high sensitivity, strong anti-interference, simple structure, high stability and low loss, and realizes highly stable and accurate angular velocity measurement, fully meeting the application requirements of high-precision inertial navigation systems.

[0024] This invention also provides a measurement method for a passive laser gyroscope based on four-frequency differential, applied to the aforementioned passive laser gyroscope based on four-frequency differential. The passive laser gyroscope includes a laser beam splitting module, a first beam locking module, a second beam locking module, a ring resonant cavity module, and a signal detection module. The ring resonant cavity module contains no gain medium. The method is executed primarily by the ring resonant cavity module, and the method includes: Receive the first laser beam output from the laser beam splitter module, which has been frequency-locked by the first beam locking module, and receive the second laser beam output from the laser beam splitter module, which has been frequency-locked by the second beam locking module. The first and second laser beams are split into reciprocal and non-reciprocal frequencies to form clockwise left-handed, clockwise right-handed, counterclockwise left-handed, and counterclockwise right-handed polarized light of different frequencies. The clockwise right-handed polarized light and the counterclockwise right-handed polarized light are coupled to form a first optical signal; The counterclockwise left-handed polarized light and the clockwise left-handed polarized light are coupled to form a second optical signal; The first optical signal and the second optical signal are output to the signal detection module, so that the signal detection module performs signal conversion and differential processing based on the first optical signal and the second optical signal, thereby enabling the signal detection module to obtain the resonant cavity angular velocity.

[0025] This invention provides a measurement method for a passive laser gyroscope based on four-frequency differential motion. It involves splitting two received locked laser beams at two frequencies to form four-frequency polarized light, which is then coupled into an output optical signal for processing by a detection module. Utilizing a ring resonant cavity with a gain-free medium design, gain medium-related noise is avoided at the source. The stable formation of four polarized beams through reciprocal and non-reciprocal frequency splitting successfully avoids the latch-up effect. Coupling the different polarized beams into two output optical signals ensures that the signal detection module can obtain clear beat frequency information. While ensuring successful four-frequency differential measurement, the method further improves measurement accuracy through a gain-free medium and low-loss design. Simultaneously, signal conversion and differential processing enhance anti-interference capabilities, ultimately achieving high-precision and high-stability resonant cavity angular velocity measurement. Attached Figure Description

[0026] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments 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 from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a passive laser gyroscope based on four-frequency differential provided in this embodiment; Figure 2 This is a schematic diagram of a passive laser gyroscope using discrete optical frequency shifting components provided in this embodiment; Figure 3 This is a schematic diagram of a passive laser gyroscope using an integrated optical rotation and reflection component provided in this embodiment; In the diagram, 100 is a laser beam splitter module; 2 is a beam splitter; 3 is a first acousto-optic modulator; 4 is a second acousto-optic modulator; 5 is a quartz crystal sheet; 6 is a Faraday magneto-optic glass; 7 is a permanent magnet; 8 is a first photodetector; 9 is a second photodetector; 10 is an optical rotation and reflection integrated component; M1 is a first input cavity mirror; M2 is a first input cavity mirror; M3 is a first output cavity mirror; M4 is a second output cavity mirror; 301 is a first reflecting mirror; 302 is a second reflecting mirror; 303 is a third reflecting mirror; 304 is a fourth reflecting mirror; 305 is a fifth reflecting mirror; 101 is a first resonant laser; 102 is a second resonant laser. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific reverse order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0033] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0034] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" 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. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0035] Example 1: This embodiment provides a passive laser gyroscope based on four-frequency differential motion, including a laser beam splitting module, a first beam locking module, a second beam locking module, a ring resonant cavity module, and a signal detection module. The ring resonant cavity module contains no gain medium. Figure 1 As shown, where: The laser beam splitting module is used to output the original laser and split the original laser into a first laser and a second laser. The first beam locking module is used to lock the frequency of the first laser, obtain the first laser path, and inject the first laser path into the annular resonant cavity module in a counterclockwise direction; The second beam locking module is used to lock the frequency of the second laser, obtain the second laser beam, and inject the second laser beam into the annular resonant cavity module in a clockwise direction; The ring resonant cavity module is used to perform reciprocal frequency splitting and non-reciprocal frequency splitting on the first and second laser beams to form clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light, and counterclockwise right-handed polarized light of different frequencies. Then, the clockwise right-handed polarized light and the counterclockwise right-handed polarized light are coupled to form a first optical signal and output to the signal detection module. The counterclockwise left-handed polarized light and the clockwise left-handed polarized light are coupled to form a second optical signal and output to the signal detection module. The signal detection module is used to perform signal conversion and differential processing based on the first optical signal and the second optical signal to obtain the resonant cavity angular velocity.

[0036] In the specific implementation process, the first beam locking module and the second beam locking module in this embodiment employ a first acousto-optic modulator and a second acousto-optic modulator, respectively, to achieve frequency shifting of the first and second laser beams. Specifically, the first acousto-optic modulator locks the frequency of the first laser beam based on the reference resonant frequency corresponding to the counterclockwise direction of the ring resonant cavity, while the second acousto-optic modulator locks the frequency of the second laser beam based on the reference resonant frequency corresponding to the clockwise direction of the ring resonant cavity. The first and second laser beams obtained after frequency locking are injected into the ring resonant cavity module in opposite directions. The signal detection module is used to detect the optical signal coupled out from the ring resonant cavity module, which contains beat frequency information of left-handed and right-handed circularly polarized light, and converts it into an electrical signal for differential processing, ultimately calculating the required resonant cavity angular velocity.

[0037] Optionally, the laser beam splitting module includes a laser source, a beam splitter, a first reflector, and a second reflector, wherein: The laser source is used to output raw laser light; The beam splitter is used to split the original laser beam into a first-direction laser and a second-direction laser with the same frequency. The first reflector is used to perform path conversion on the laser beam in the first direction to obtain the first laser beam; The second reflector is used to perform path conversion on the laser in the second direction to obtain the second laser.

[0038] In the specific implementation process, the laser source is realized by a laser, which is used to output a raw laser of a certain wavelength, and the beam splitter divides the raw laser into two paths.

[0039] Optionally, the ring resonant cavity module includes a ring resonant cavity, a first input cavity mirror, a second input cavity mirror, and an output cavity mirror. The ring resonant cavity contains no gain medium, wherein: The first input cavity mirror is used to receive the first laser beam and input it into the annular resonant cavity; The second input cavity mirror is used to receive the second laser beam and input it into the annular resonant cavity; The ring resonant cavity is provided with an optical frequency polarization component, which is used to transmit the first laser and the second laser to the optical frequency polarization component, so that the optical frequency polarization component performs reciprocal frequency splitting and non-reciprocal frequency splitting on the first laser and the second laser to form clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light and counterclockwise right-handed polarized light. The output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module, and to couple the counterclockwise left-handed polarized light and the clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

[0040] In practical implementation, the ring resonator is a passive optical resonator without an internal gain medium, used to simultaneously resonate clockwise and counterclockwise left-handed and right-handed circularly polarized light with different frequencies. The optical polarization component is used to introduce reciprocal and non-reciprocal frequency splitting into the opposing beams.

[0041] Optionally, the output cavity mirror includes a first output cavity mirror and a second output cavity mirror, wherein: The first output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module; The second output cavity mirror is used to couple counterclockwise left-handed polarized light and clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

[0042] In this specific implementation, the ring resonant cavity used is a quadrilateral cavity. The laser in the ring resonant cavity is injected from the outside, that is, the first laser obtained through the first acousto-optic modulator and the second laser obtained through the second acousto-optic modulator are injected into the cavity in clockwise and counterclockwise directions, respectively.

[0043] Preferably, the annular resonant cavity is a square resonant cavity composed of two input cavity mirrors and two output cavity mirrors; wherein both the input cavity mirrors and the output cavity mirrors are high reflectivity cavity mirrors, so that the laser injected from one of the input cavity mirrors propagates clockwise in the annular resonant cavity, and the laser injected from the other input cavity mirror propagates counterclockwise in the annular resonant cavity.

[0044] Optional: The optical polarization component includes discrete reciprocal rotators and non-reciprocal rotators.

[0045] In specific implementation, the reciprocal optical rotator in the instinctive embodiment uses a quartz crystal sheet; the non-reciprocal optical rotator uses Faraday magneto-optical glass, and a permanent magnet is provided on its outer side to provide an axial magnetic field. The discrete optical polarization component is composed of a quartz crystal sheet and Faraday magneto-optical glass with a permanent magnet placed sequentially.

[0046] Preferably, to suppress backscattering, the non-reciprocal rotator can be installed at a preset tilt angle, that is, it can be tilted at a small angle during installation.

[0047] Optionally, the ring resonant cavity module includes a first input cavity mirror, a second input cavity mirror, a ring resonant cavity, and an output cavity mirror; wherein: The first input cavity mirror is used to receive the first laser beam and input it into the annular resonant cavity; The second input cavity mirror is used to receive the second laser beam and input it into the annular resonant cavity; The annular resonant cavity is equipped with an optical rotation and reflection integrated component, which is used to transmit the first laser and the second laser in an oblique incidence manner to the optical rotation and reflection integrated component, so that the optical rotation and reflection integrated component performs reciprocal optical rotation, non-reciprocal Faraday rotation and reflection on the first laser and the second laser, forming clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light and counterclockwise right-handed polarized light; The output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module, and to couple the counterclockwise left-handed polarized light and the clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

[0048] Optionally, the optical rotation and reflection integrated component includes an optical rotation and reflection integrated structure, an anti-reflection coating, an anti-reflection coating, and a permanent magnet; wherein: The antireflective film is disposed on the inner surface of the optical rotation and reflection integrated structure; The anti-reflective coating is disposed on the outer surface of the optical rotation and reflection integrated structure in the first direction; The permanent magnet is disposed on the outer side of the optical rotation and reflection integrated structure in the second direction.

[0049] Preferably, the oblique incidence method in this embodiment is Brewster angle incidence.

[0050] In practical implementation, the integrated optical rotation and reflection assembly can simultaneously achieve reciprocal optical rotation, non-reciprocal Faraday rotation, and reflection functions. Furthermore, an anti-reflection coating is deposited on the inner surface of the integrated optical rotation and reflection structure within the assembly, while an anti-reflection coating is deposited on the outer surface. This reduces reflection losses on the inner surface and transmission losses on the outer surface. The laser is positioned to enter the assembly at an oblique incidence, and a high-reflection coating is used; that is, the laser is incident at a Brewster angle, with an anti-reflection coating on the inner surface and a high-reflection coating on the outer surface, thus minimizing losses and scattering.

[0051] Optionally, the signal detection module includes a first photodetector, a second photodetector, and a signal processing unit, wherein: The first photodetector is used to perform signal conversion based on the first optical signal to obtain the first beat frequency signal; The second photodetector is used to perform signal conversion based on the second optical signal to obtain the second beat frequency signal; The signal processing unit is used to perform differential processing on the first beat frequency signal and the second beat frequency signal to obtain the resonant cavity angular velocity.

[0052] In the specific implementation process, the signal detection module includes at least two photodetectors, which are used to detect the beat frequency signals of the light field propagating in the clockwise and counterclockwise directions, respectively; the differential processing is to subtract the two beat frequency signals to eliminate the non-reciprocal frequency deviation and obtain the difference frequency signal proportional to the input angular velocity.

[0053] In the specific implementation process, the signal detection module is also equipped with a reflector for adjusting the optical path injected into the photodetector. Specifically, when the ring resonant cavity is equipped with an optical frequency polarization component, and the signal detection module includes a first photodetector and a second photodetector, this embodiment uses a reflector including a third reflector and a fourth reflector. The third reflector is used to receive the first optical signal output from the first output cavity mirror and transmit it to the first photodetector, and the fourth reflector is used to receive the second optical signal output from the second output cavity mirror and transmit it to the second photodetector. When the ring resonant cavity is equipped with an optical rotation reflection integrated component, and the signal detection module includes a first photodetector and a second photodetector, since the optical rotation reflection integrated component is set up, only one output cavity mirror (removing the first output cavity mirror and retaining only the fourth output cavity mirror) outputs the first and second optical signals. Therefore, only one reflector (a fifth reflector) needs to be set up in front of the second photodetector to adjust the optical path and ensure that the two optical signals are consistent with the propagation conditions injected into the ring resonant cavity, thus achieving functional symmetry of the optical path.

[0054] In the specific implementation process, when the signal processing unit calculates the angular velocity of the resonant cavity, since the clockwise propagating CW (clockwise) light field and the counterclockwise propagating CCW (counterclockwise) light field within the ring resonant cavity each contain left-handed circularly polarized light and right-handed circularly polarized light, the two paths of left-handed circularly polarized light (i.e., the counterclockwise left-handed circularly polarized light and the clockwise left-handed circularly polarized light) form a left-handed gyroscope, and its first beat frequency signal... Detected by the first photodetector; a right-handed gyroscope composed of two paths of right-handed circularly polarized light (i.e., clockwise and counterclockwise right-handed polarized light), and its second beat frequency signal. Detected by a second photodetector. The two beat frequency signals are approximated by the following formulas: ; ; In the formula: K represents the gyroscope scaling factor, and Ω represents the input angular velocity (i.e., the current resonant cavity angular velocity). The subsequent signal processing unit's signal processing circuit performs a differential operation on the two beat frequency signals, as shown in the following formula: ; From this, a signal proportional to the angular velocity Ω can be calculated. This eliminates the non-reciprocal bias of the common mode, thereby obtaining the required resonant cavity angular velocity.

[0055] Optionally, a frequency-locking loop is also included, wherein: the signal detection module is further configured to acquire a first frequency error signal and a second frequency error signal based on the first optical signal, the second optical signal, and the resonant cavity reference frequency; the frequency-locking loop is configured to: The first frequency error signal and the second frequency error signal are subjected to drive conversion processing to obtain the first frequency adjustment signal and the second frequency adjustment signal; The first frequency adjustment signal is input to the first beam locking module, so that the first beam locking module performs drive frequency adjustment based on the first frequency adjustment signal; The second frequency adjustment signal is input to the second beam locking module, so that the second beam locking module performs drive frequency adjustment based on the second frequency adjustment signal.

[0056] In the specific implementation process, the frequency locking loop controls the driving frequency of the first and second acousto-optic modulators through the error signal feedback generated by the signal detection module, so that the injected laser frequency tracks and locks the resonant frequency of the annular resonant cavity in real time.

[0057] In practice, the laser source outputs a fixed single-frequency laser. However, due to differences in physical structure, the clockwise (CW) and counterclockwise (CCW) optical paths of the ring resonant cavity each have their own corresponding resonant cavity reference frequencies. The original single-frequency laser cannot simultaneously match the resonant frequencies of the two optical paths. At this point, the core function of the first and second acousto-optic modulators is to shift the frequency of the two split laser beams. By changing their own driving frequencies, the frequencies of the two laser beams are adjusted to match the reference frequencies of the clockwise and counterclockwise resonant cavities, respectively, ensuring that the laser can resonate stably within the passive cavity, thereby forming a beat frequency signal containing angular velocity information.

[0058] In this implementation, a PDH (Phase Detector-Hysteresis Locked Loop, a phase detection-type locking loop with hysteresis characteristics) is introduced for real-time feedback, forming a frequency-locked loop. A photodetector collects the reflected light signals (i.e., the first and second optical signals) in the CW and CCW directions of the resonant cavity, and coherently demodulates these reflected signals with a modulation reference signal (i.e., the resonant cavity reference frequency). Since the reflected light signals are highly sensitive to deviations between the laser frequency and the cavity resonant frequency, after demodulation and low-pass filtering, excellent linearity in the first and second frequency error signals can be obtained. These frequency error signals are processed by a servo circuit to adjust the driving frequency of the AOM (Acousto-Optic Modulator) in real time, i.e., adjusting the driving frequency of the first and second beam-locking modules respectively, ensuring that the two injected laser beams are always accurately locked to the resonant peak of the cavity. Finally, the difference between the driving frequencies of the two AOMs is monitored through the two beams output from the ring resonant cavity, thereby calculating high-precision angular velocity information. It is important to note that since four beams of light at different frequencies need to be locked onto the ring resonator, external PDH locking and modulation of the magnetic field are required to lock all four laser beams simultaneously. Furthermore, to ensure effective locking, the frequency shift of the quartz crystal should be designed to be nFSR, meaning the frequency shift of the left-handed or right-handed circularly polarized light after passing through the quartz crystal should be equal to n times the frequency interval between adjacent transmission peaks of the ring resonator.

[0059] This embodiment provides a passive laser gyroscope based on four-frequency differential motion, aiming to solve the gain medium-related noise sources such as mode competition and discharge noise introduced by active laser gyroscopes, while also addressing the backscattering problem caused by perpendicular laser incidence on traditional optical rotators. By injecting a locked laser outside the ring resonant cavity, the noise source caused by the gain medium in active gyroscopes is fundamentally eliminated. Backscattering is effectively suppressed through the tilted mounting of discrete optical rotators or the oblique incidence design of the integrated optical rotator reflection assembly, thereby reducing intracavity losses. The overall design employs a single laser combined with dual acousto-optic modulators, avoiding the complexity of multi-laser systems and achieving integrated design, further improving the simplicity and reliability of the passive laser gyroscope. This passive laser gyroscope combines the high sensitivity and common-mode noise suppression capability of four-frequency differential motion technology with the low noise potential of passive laser gyroscopes, perfectly realizing four-frequency differential measurement in a passive cavity while maintaining simplicity, stability, and high performance, enabling high-precision angular velocity measurement.

[0060] Example 2: This embodiment also provides a measurement method for a passive laser gyroscope based on four-frequency differential, applied to the aforementioned passive laser gyroscope based on four-frequency differential. The passive laser gyroscope includes a laser beam splitting module, a first beam locking module, a second beam locking module, a ring resonant cavity module, and a signal detection module. The ring resonant cavity module has no gain medium. The method is executed primarily by the ring resonant cavity module, and the method includes: Receive the first laser beam output from the laser beam splitter module, which has been frequency-locked by the first beam locking module, and receive the second laser beam output from the laser beam splitter module, which has been frequency-locked by the second beam locking module. The first and second laser beams are split into reciprocal and non-reciprocal frequencies to form clockwise left-handed, clockwise right-handed, counterclockwise left-handed, and counterclockwise right-handed polarized light of different frequencies. The clockwise right-handed polarized light and the counterclockwise right-handed polarized light are coupled to form a first optical signal; The counterclockwise left-handed polarized light and the clockwise left-handed polarized light are coupled to form a second optical signal; The first optical signal and the second optical signal are output to the signal detection module, so that the signal detection module performs signal conversion and differential processing based on the first optical signal and the second optical signal, thereby enabling the signal detection module to obtain the resonant cavity angular velocity.

[0061] Example 3: Based on the passive laser gyroscope based on four-frequency differential described in Embodiment 1, this embodiment provides a passive laser gyroscope employing discrete optical frequency-biasing components, such as... Figure 2 As shown, the passive laser gyroscope includes a laser beam splitter module 100, a ring resonant cavity module 200, a signal detection module 300, a beam splitter 2, a first acousto-optic modulator 3, a second acousto-optic modulator 4, a quartz crystal 5, a Faraday magneto-optical glass 6, a permanent magnet 7, a first photodetector 8, a second photodetector 9, a first input cavity mirror M1, a first input cavity mirror M2, a first output cavity mirror M3, a second output cavity mirror M4, a first reflector 301, a second reflector 302, a third reflector 303, and a fourth reflector 304. The laser beam splitter module 100 outputs a first laser beam 101 and a second laser beam 102. The permanent magnet 7 includes an N pole and a S pole. The ring resonant cavity is a quadrilateral passive cavity formed by four high-reflectivity cavity mirrors (M1, M2, M3, and M4).

[0062] In the specific implementation process, the frequency of the laser source output is: The linearly polarized laser is split into two paths by beam splitter 2. The first laser 101 is locked by the first acousto-optic modulator 3 and injected into the ring resonant cavity by the first input cavity mirror M1 to form a CCW propagation light field. The second laser 102 is locked by the second acousto-optic modulator 4 and injected into the ring resonant cavity by the second input cavity mirror M2 to form a CW propagation light field. The CCW propagation light field is injected by M1, and its resonant light is output to the second photodetector 9 by M3; the CW propagation light field is injected by M2, and its resonant light is output to the first photodetector 8 by M4.

[0063] Preferably, by tilting the non-reciprocal rotator (Faraday magneto-optical glass 6) at a small angle (1~5° is sufficient), backscattering is suppressed because the reflected light from its surface is deviated from the main optical path of the resonant cavity. The reciprocal rotator provides reciprocal frequency splitting. Non-reciprocal rotators provide non-reciprocal frequency shift. .

[0064] Example 4: Based on Embodiments 1 and 3, this embodiment provides a passive laser gyroscope employing an integrated optical rotation and reflection assembly. The difference from Embodiment 3 lies in the structure of the optical polarization assembly, such as... Figure 3 As shown, the passive laser gyroscope includes a laser beam splitter module 100, a ring resonant cavity module 200, a signal detection module 300, a beam splitter 2, a first acousto-optic modulator 3, a second acousto-optic modulator 4, a first photodetector 8, a second photodetector 9, a rotational reflection integrated component 10, a first input cavity mirror M1, a first input cavity mirror M2, a second output cavity mirror M4, a first reflector 301, a second reflector 302, and a fifth reflector 305. The laser beam splitter module 100 outputs a first laser 101 and a second laser 102. The permanent magnet 7 includes an N pole and a S pole.

[0065] In the specific implementation process, the frequency of the laser source output is: The linearly polarized laser is split into two paths by beam splitter 2. The first laser 101 is locked by the first acousto-optic modulator 3 and injected into the optical rotation and reflection integrated component 10 at a Brewster angle. The laser beam is then reflected on the outer surface of the component, which is coated with a high-reflectivity film. During the laser's entry and exit from the component, both Faraday non-reciprocal and reciprocal optical rotations are completed simultaneously. The reflected light is injected into the cavity at a specific angle, forming a CCW propagation path. The second laser 102 is locked by the second acousto-optic modulator 4 and injected into the cavity via M2, forming a CW propagation path. In the CW propagation path, the beam is injected through M2 and output from M3 to the first photodetector 8; the CCW beam is injected through M1 and output from M3 to the second photodetector 9.

[0066] The laser is incident at Brewster's angle in the optical rotation and reflection integrated component 10, which can suppress reflection loss and backscattering from the optical surface, thereby reducing intracavity loss and measurement noise. Simultaneously, the integrated design of the optical rotation and reflection integrated component 10 reduces the number of discrete components, effectively improving the stability and reliability of the system.

[0067] In the specific implementation process, this embodiment uses pure s-light (linearly polarized light whose electric field vibration direction is completely perpendicular to the incident surface) or pure p-light (linearly polarized light whose electric field vibration direction is completely parallel to the incident surface) as incident light, that is, linearly polarized light with a single polarization state. When the first reflector 301, the second reflector 302, the third reflector 303, the fourth reflector 304 and the fifth reflector 305 are used as reflectors to adjust the path, only their light intensity is affected.

[0068] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A passive laser gyroscope based on four-frequency differential, characterized in that, It includes a laser beam splitting module, a first beam locking module, a second beam locking module, a ring resonant cavity module, and a signal detection module. The ring resonant cavity module contains no gain medium. The laser beam splitting module is used to output the original laser and split the original laser into a first laser and a second laser. The first beam locking module is used to lock the frequency of the first laser, obtain the first laser path, and inject the first laser path into the annular resonant cavity module in a counterclockwise direction; The second beam locking module is used to lock the frequency of the second laser, obtain the second laser beam, and inject the second laser beam into the annular resonant cavity module in a clockwise direction; The ring resonant cavity module is used to perform reciprocal frequency splitting and non-reciprocal frequency splitting on the first and second laser beams to form clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light, and counterclockwise right-handed polarized light of different frequencies. Then, the clockwise right-handed polarized light and the counterclockwise right-handed polarized light are coupled to form a first optical signal and output to the signal detection module. The counterclockwise left-handed polarized light and the clockwise left-handed polarized light are coupled to form a second optical signal and output to the signal detection module. The signal detection module is used to perform signal conversion and differential processing based on the first optical signal and the second optical signal to obtain the resonant cavity angular velocity.

2. A passive laser gyroscope based on four-frequency differential as described in claim 1, characterized in that, The laser beam splitting module includes a laser source, a beam splitter, a first reflector, and a second reflector, wherein: The laser source is used to output raw laser light; The beam splitter is used to split the original laser beam into a first-direction laser and a second-direction laser with the same frequency. The first reflector is used to perform path conversion on the laser beam in the first direction to obtain the first laser beam; The second reflector is used to perform path conversion on the laser in the second direction to obtain the second laser.

3. A passive laser gyroscope based on four-frequency differential as described in claim 1, characterized in that, The ring resonant cavity module includes a ring resonant cavity, a first input cavity mirror, a second input cavity mirror, and an output cavity mirror. The ring resonant cavity contains no gain medium. The first input cavity mirror is used to receive the first laser beam and input it into the annular resonant cavity; The second input cavity mirror is used to receive the second laser beam and input it into the annular resonant cavity; The ring resonant cavity is provided with an optical frequency polarization component, which is used to transmit the first laser and the second laser to the optical frequency polarization component, so that the optical frequency polarization component performs reciprocal frequency splitting and non-reciprocal frequency splitting on the first laser and the second laser to form clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light and counterclockwise right-handed polarized light. The output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module, and to couple the counterclockwise left-handed polarized light and the clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

4. A passive laser gyroscope based on four-frequency differential as described in claim 3, characterized in that, The output cavity mirror includes a first output cavity mirror and a second output cavity mirror, wherein: The first output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module; The second output cavity mirror is used to couple counterclockwise left-handed polarized light and clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

5. A passive laser gyroscope based on four-frequency differential as described in claim 3, characterized in that: The optical polarization component includes discrete reciprocal rotators and non-reciprocal rotators.

6. A passive laser gyroscope based on four-frequency differential as described in claim 1, characterized in that, The ring resonant cavity module includes a first input cavity mirror, a second input cavity mirror, a ring resonant cavity, and an output cavity mirror; wherein: The first input cavity mirror is used to receive the first laser beam and input it into the annular resonant cavity; The second input cavity mirror is used to receive the second laser beam and input it into the annular resonant cavity; The annular resonant cavity is equipped with an optical rotation and reflection integrated component, which is used to transmit the first laser and the second laser in an oblique incidence manner to the optical rotation and reflection integrated component, so that the optical rotation and reflection integrated component performs reciprocal optical rotation, non-reciprocal Faraday rotation and reflection on the first laser and the second laser, forming clockwise left-handed polarized light, clockwise right-handed polarized light, counterclockwise left-handed polarized light and counterclockwise right-handed polarized light; The output cavity mirror is used to couple the clockwise right-handed polarized light and the counterclockwise right-handed polarized light to form a first optical signal and output it to the signal detection module, and to couple the counterclockwise left-handed polarized light and the clockwise left-handed polarized light to form a second optical signal and output it to the signal detection module.

7. A passive laser gyroscope based on four-frequency differential as described in claim 6, characterized in that, The optical rotation and reflection integrated component includes an optical rotation and reflection integrated structure, an anti-reflection coating, an anti-reflective coating, and a permanent magnet; wherein: The antireflective film is disposed on the inner surface of the optical rotation and reflection integrated structure; The anti-reflective coating is disposed on the outer surface of the optical rotation and reflection integrated structure in the first direction; The permanent magnet is disposed on the outer side of the optical rotation and reflection integrated structure in the second direction.

8. A passive laser gyroscope based on four-frequency differential as described in claim 1, characterized in that, The signal detection module includes a first photodetector, a second photodetector, and a signal processing unit, wherein: The first photodetector is used to perform signal conversion based on the first optical signal to obtain the first beat frequency signal; The second photodetector is used to perform signal conversion based on the second optical signal to obtain the second beat frequency signal; The signal processing unit is used to perform differential processing on the first beat frequency signal and the second beat frequency signal to obtain the resonant cavity angular velocity.

9. A passive laser gyroscope based on four-frequency differential as described in claim 1, characterized in that, It also includes a frequency-locking loop, wherein: the signal detection module is further configured to acquire a first frequency error signal and a second frequency error signal based on the first optical signal, the second optical signal, and the resonant cavity reference frequency; the frequency-locking loop is configured to: The first frequency error signal and the second frequency error signal are subjected to drive conversion processing to obtain the first frequency adjustment signal and the second frequency adjustment signal; The first frequency adjustment signal is input to the first beam locking module, so that the first beam locking module performs drive frequency adjustment based on the first frequency adjustment signal; The second frequency adjustment signal is input to the second beam locking module, so that the second beam locking module performs drive frequency adjustment based on the second frequency adjustment signal.

10. A measurement method based on a four-frequency differential passive laser gyroscope, characterized in that, Applied to a passive laser gyroscope based on four-frequency differential as described in any one of claims 1-9, wherein the passive laser gyroscope includes a laser beam splitting module, a first beam locking module, a second beam locking module, a ring resonant cavity module, and a signal detection module, wherein the ring resonant cavity module has no gain medium, the method execution subject is the ring resonant cavity module, and the method includes: Receive the first laser beam output from the laser beam splitter module, which has been frequency-locked by the first beam locking module, and receive the second laser beam output from the laser beam splitter module, which has been frequency-locked by the second beam locking module. The first and second laser beams are split into reciprocal and non-reciprocal frequencies to form clockwise left-handed, clockwise right-handed, counterclockwise left-handed, and counterclockwise right-handed polarized light of different frequencies. The clockwise right-handed polarized light and the counterclockwise right-handed polarized light are coupled to form a first optical signal; The counterclockwise left-handed polarized light and the clockwise left-handed polarized light are coupled to form a second optical signal; The first optical signal and the second optical signal are output to the signal detection module, so that the signal detection module performs signal conversion and differential processing based on the first optical signal and the second optical signal, thereby enabling the signal detection module to obtain the resonant cavity angular velocity.

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