Resonator optical gyroscope driven by wide spectrum light source based on light intensity fluctuation feedback and RIN suppression method thereof

Abstract

The application belongs to the field of optical gyroscopes, and particularly relates to a wide-spectrum light source driven resonant optical gyroscope based on light intensity fluctuation feedback technology and a RIN suppression method thereof. The light source ASE is connected with a No.1 port of a circulator CIR, the No.2 port of the circulator CIR is connected with a micro integrated optical waveguide modulator MIOC, the tail end of the micro integrated optical waveguide modulator MIOC is connected with one end of a coupler C1 and one end of a coupler C2 respectively, the other end of the coupler C1 and the other end of the coupler C2 are connected with a fiber resonant cavity FRR respectively to realize multi-turn transmission of light in the fiber resonant cavity FRR; the polarization maintaining optical fiber extended from the right transmission end of the coupler C2 is connected with the No.3 output end of the circulator CIR after 90-degree fusion, and then connected with one side of a coupler C3, and the light intensity signal output by the coupler C3 is detected by a photodetector PD, and then output as a rotation value after passing through a lock-in amplifier LIA and a low-pass filter LPF. The application can actively suppress the light intensity fluctuation caused by the light source at a specific frequency.

Description

Technical Field

[0001] This invention belongs to the field of optical gyroscopes; specifically, it relates to a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback and its RIN suppression method. Background Technology

[0002] A gyroscope is a sensor capable of accurately determining the angular velocity of a moving object. It is a widely used inertial navigation instrument in modern aviation, navigation, aerospace, and defense industries. In recent years, the rapid development of inertial technology has placed higher demands on inertial devices. While ensuring high precision, they are also required to possess characteristics such as small size, low power consumption, high reliability, low cost, and resistance to vibration and shock. The development level of gyroscopes directly affects the key performance of inertial navigation and guidance systems, playing an irreplaceable role in the defense field.

[0003] Currently, in the field of optical gyroscopes, laser gyroscopes have numerous internal optoelectronic components, making them difficult and costly to manufacture. The accuracy of interferometric fiber optic gyroscopes is related to the length of the internal fiber loop; high-precision interferometric fiber optic gyroscopes require loops several kilometers long, making miniaturization difficult. In contrast, resonant optical gyroscopes detect rotational angular rate by detecting the resonant frequency difference of opposing beams propagating within the cavity due to the Sagnac effect. Using the resonant cavity as its core sensing component, these gyroscopes can be miniaturized to the millimeter level, aligning with the trend towards device miniaturization. Furthermore, they offer high fabrication repeatability, device integration capabilities, and sensitivity.

[0004] Recently, a resonant fiber optic gyroscope driven by a broadband light source has been proposed to reduce coherent noise. This approach features simple optical configuration and signal processing methods, eliminating the need for laser frequency locking or other complex coherent noise handling. This method suppresses optical noise, such as backscatter noise, where light intensity fluctuations have become a major source of error in the gyroscope output. To suppress relative intensity noise (RIN), which significantly affects angular random walk (ARW), a high-frequency modulation technique is proposed. This method analyzes the RIN spectrum and optimizes the modulation frequency to demodulate the gyroscope signal at the lowest possible RIN. Another approach suppresses RIN by establishing a relationship between the demodulation slope and RIN. By optimizing the modulation parameters and improving the fineness of the FRR, a steep slope can be achieved, thereby reducing errors caused by RIN. The above methods provide a passive approach to suppressing RIN, allowing the gyroscope to operate at the lowest point in the noise spectrum. Therefore, the short-term accuracy of the gyroscope still depends on the background noise of the light source. Summary of the Invention

[0005] This invention provides a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback, which can actively suppress light intensity fluctuations caused by the light source at specific frequencies.

[0006] This invention provides a method for suppressing broadband light source-driven resonant optical gyroscopes based on light intensity fluctuation feedback, which can actively suppress light intensity fluctuations caused by the light source at specific frequencies.

[0007] This invention is achieved through the following technical solution:

[0008] A broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback, the gyroscope comprising a light source ASE, a circulator CIR, a miniature integrated optical waveguide modulator MIOC, couplers C1 and C2, an optical fiber resonator FRR, a coupler C3, a photodetector PD, a lock-in amplifier LIA, and a low-pass filter LPF.

[0009] The light source ASE is connected to port 1 of the circulator CIR, and port 2 of the circulator CIR is connected to the miniature integrated optical waveguide modulator MIOC. The tail end of the miniature integrated optical waveguide modulator MIOC is connected to one end of coupler C1 and one end of coupler C2, respectively. The other end of coupler C1 and the other end of coupler C2 are respectively connected to the fiber resonator FRR to realize multi-turn transmission of light in the fiber resonator FRR.

[0010] The polarization-maintaining fiber extending from the right transmission end of the coupler C2 is fused at 90 degrees and connected to the No. 3 output end of the circulator CIR, and then connected to one side of the coupler C3. The light intensity signal output by the coupler C3 is detected by the photodetector PD, passed through the lock-in amplifier LIA and the low-pass filter LPF, and then output as the rotation speed value.

[0011] Furthermore, the working light source ASE is used to generate a broadband rectangular light field;

[0012] The circulator CIR is used to transmit the optical field in the forward direction and to split the optical field to the coupler C3 when it is transmitted in the reverse direction.

[0013] The micro-integrated optical waveguide modulator (MIOC) is used to modulate the frequency and phase of the incident and outgoing light fields.

[0014] The coupler C1, coupler C2 and fiber resonant cavity FRR together form a resonant angular velocity sensing element, which is an important part of generating the Sagnac effect;

[0015] The coupler C3 is used to combine the feedback light output from the circulator CIR3 segment with the direct light output from the transmission end of C2 to cancel out light intensity fluctuations at a specific frequency.

[0016] The photodetector PD is used to receive the optical signal emitted by C3 and convert the optical signal into an electrical signal;

[0017] The lock-in amplifier LIA is used to synchronously demodulate the signal and output signals to the low-pass filter LPF and the micro-integrated optical waveguide modulator MIOC, respectively.

[0018] The low-pass filter (LPF) is used to filter the synchronously demodulated signal.

[0019] Furthermore, the gyroscope can also be driven by white light.

[0020] A method for suppressing RIN (Resonance Intensity) in a broadband light source driven resonant optical gyroscope based on intensity fluctuation feedback, characterized in that the suppression method uses the broadband light source driven resonant optical gyroscope based on intensity fluctuation feedback as described above, and the suppression method includes:

[0021] After the light field required for angular velocity detection is emitted by the light source ASE, the phase of the light field is modulated and split by the micro integrated optical waveguide modulator MIOC. The split light enters the fiber resonator FRR respectively and propagates clockwise and counterclockwise along the fiber resonator FRR.

[0022] After multiple turns of transmission via the resonant cavity FRR, one beam of light is output from coupler C2, then enters coupler C3 via 90° fusion splicing, and the other beam of light is combined and returned by the micro integrated optical waveguide modulator MIOC, then output from port 3 of the circulator CIR via port 2, and enters coupler C3.

[0023] Since the two beams of light entering coupler C3 are not on the same polarization axis, their light intensities are superimposed after passing through coupler C3.

[0024] The signal light output by coupler C3 is detected by photodetector PD. The photodetector PD converts the light intensity signal into an electrical signal, which is then demodulated by lock-in amplifier LIA. The rotation speed signal carried in the modulation signal is demodulated and stripped out, and then output as the gyroscope rotation speed signal through low-pass filter LPF.

[0025] Furthermore, the feature is that, due to the influence of the lock-in amplifier LIA9, the light intensity fluctuation after passing through the fiber resonator FRR is expressed as follows in the unmodulated case:

[0026] (1)

[0027] (2)

[0028] (3)

[0029] (4)

[0030] in, It is the coupling coefficient; It is the light transmission time delay in FRR; K It is transmission loss; B It is the superposition value of light intensity fluctuations; D It refers to the range of light intensity fluctuations; b It is the light intensity fluctuation function at the modulation frequency; w and It is the focusing fluctuation frequency and its random phase caused by relative intensity noise RIN; , c and L These are the refractive index of the optical fiber, the speed of light, and the length of the FRR (fiber refractive index).

[0031] Furthermore, it is assumed that the RIN exhibits sinusoidal fluctuations at a specific demodulation frequency; after time delay and superposition of different numbers of cycles, it retains its sinusoidal shape;

[0032] Due to the fixed length difference in the light propagation path, different phase differences cause fluctuations in light intensity. Therefore, adjustments are needed to ensure that the phase difference is within acceptable limits. .

[0033] A test method for RIN suppression of a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback. The test method uses the RIN suppression method of the broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback as described above. The test method requires specific frequency fluctuation phase difference testing of the constructed optical path.

[0034] Two photodetectors are placed after one of the transmission end free ports of coupler C2 and port 3 of circulator CIR; instead of applying any modulation signal to the micro-integrated optical waveguide modulator MIOC, a sine wave and a cosine wave of the same frequency and phase are generated using signal generator SG; these two signals are multiplied by PD1 and PD2 respectively to calculate the phase difference.

[0035] Furthermore, the specific frequency fluctuation phase difference test is calculated as follows:

[0036] (5)

[0037] (6)

[0038] (7)

[0039] in, It is a signal from PD1 or PD2; It is the angular frequency of the signal from the signal generator SG; and and The signal output by SG The signal multiplied by sine and cosine waves; and yes and The signal is processed by a low-pass filter (LPF); a series of test samples are obtained by adjusting the signal frequency of SG from a lower frequency to a higher frequency. and The phase difference is calculated as follows: .

[0040] Furthermore, after standardizing a series of samples and calculating their statistical information, the phase difference of light intensity fluctuations at different modulation frequencies is obtained; the demodulation frequency is gradually adjusted until the demodulation phase difference is π.

[0041] Furthermore, the light source ASE emits white light to drive the resonant optical gyroscope.

[0042] The beneficial effects of this invention are:

[0043] This invention employs an ASE broadband light source to drive a resonant optical gyroscope, effectively utilizing the optical power at the idle end of the coupler and performing feedback compensation to cancel out light intensity fluctuations at specific frequencies. Furthermore, this method represents active compensation for RIN suppression. Compared to existing passive methods (operating the gyroscope at the lowest point of the noise power spectrum), this method theoretically can completely eliminate light intensity fluctuations at specific frequencies and has lower requirements for the relative intensity noise quality of the light source. By setting this structure, light intensity fluctuations can be effectively reduced, the impact of RIN on the gyroscope output can be decreased, and the gyroscope's angular random walk accuracy can be significantly improved. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the present invention.

[0045] Figure 2 This is a schematic diagram of the optical path relative intensity noise spectrum test of the present invention.

[0046] Figure 3 This is a schematic diagram illustrating the technical verification of the present invention.

[0047] Figure 4 This invention relates to the method of modulation and demodulation at different frequencies, by Figure 3 A schematic diagram of the phase difference distribution of light intensity fluctuations obtained from structural testing, where (a) is 400kHz, (b) is 800kHz, (c) is 1500kHz, and (d) is 1830kHz. Detailed Implementation

[0048] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0049] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0050] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0051] The following is in conjunction with the appendix to this application specification. Figure 1-4 The technical solutions in the embodiments of this application are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0052] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0053] Implementation Method 1

[0054] This embodiment provides a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback. The gyroscope includes a light source ASE, a circulator CIR, a miniature integrated optical waveguide modulator MIOC, a coupler C1, a coupler C2, an optical fiber resonator FRR, a coupler C3, a photodetector PD, a lock-in amplifier LIA, and a low-pass filter LPF.

[0055] The light source ASE is connected to port 1 of the circulator CIR, and port 2 of the circulator CIR is connected to the micro-integrated optical waveguide modulator MIOC. After the micro-integrated optical waveguide modulator MIOC splits the beam into equal power beams, its tail end is connected to one end of coupler C1 and one end of coupler C2, respectively. The other end of coupler C1 and the other end of coupler C2 are respectively connected to the fiber resonator FRR to realize multi-turn transmission of light in the fiber resonator FRR.

[0056] The right-side transmission end interface of the coupler C1 is idle. The polarization-maintaining fiber extended from the right-side transmission end of the coupler C2 is fused at 90 degrees and then connected to the No. 3 output end of the circulator CIR, and then connected to one side of the coupler C3. The light intensity signal output by the coupler C3 is detected by the photodetector PD, passed through the lock-in amplifier LIA and the low-pass filter LPF, and then output as the rotation speed value.

[0057] Furthermore, the working light source ASE is used to generate a broadband rectangular light field;

[0058] The circulator CIR is used to transmit the optical field in the forward direction and to split the optical field to the coupler C3 when it is transmitted in the reverse direction.

[0059] The micro-integrated optical waveguide modulator (MIOC) is used to modulate the frequency (phase) of the incident and outgoing light fields.

[0060] The coupler C1, coupler C2 and fiber resonant cavity FRR together form a resonant angular velocity sensing element, which is an important part of generating the Sagnac effect;

[0061] The coupler C3 is used to combine the feedback light output from the circulator CIR3 segment with the direct light output from the transmission end of C2 to cancel out light intensity fluctuations at a specific frequency.

[0062] The photodetector PD is used to receive the optical signal emitted by C3 and convert the optical signal into an electrical signal;

[0063] The lock-in amplifier LIA is used to synchronously demodulate the signal and output signals to the low-pass filter LPF and the micro-integrated optical waveguide modulator MIOC, respectively.

[0064] The low-pass filter (LPF) is used to filter the synchronously demodulated signal.

[0065] Furthermore, the gyroscope can also be driven by white light.

[0066] Implementation Method 2

[0067] This embodiment provides a RIN suppression method for a broadband light source driven resonant optical gyroscope based on intensity fluctuation feedback. The suppression method uses a broadband light source driven resonant optical gyroscope based on intensity fluctuation feedback as described in Embodiment 1. The suppression method includes:

[0068] After the light field required for angular velocity detection is emitted by the light source ASE, the phase of the light field is modulated and split by the micro integrated optical waveguide modulator MIOC. The split light enters the fiber resonator FRR respectively and propagates clockwise and counterclockwise along the fiber resonator FRR.

[0069] After multiple turns of transmission via the resonant cavity FRR, one beam of light is output from coupler C2, then enters coupler C3 via 90° fusion splicing, and the other beam of light is combined and returned by the micro integrated optical waveguide modulator MIOC, then output from port 3 of the circulator CIR via port 2, and enters coupler C3.

[0070] Since the two beams of light entering coupler C3 are not on the same polarization axis, their light intensities are superimposed after passing through coupler C3.

[0071] The signal light output by coupler C3 is detected by photodetector PD. The photodetector PD converts the light intensity signal into an electrical signal, which is then demodulated by lock-in amplifier LIA. The rotation speed signal carried in the modulation signal is demodulated and stripped out, and then output as the gyroscope rotation speed signal through low-pass filter LPF.

[0072] Specifically, the light output from C2 largely bypasses the FRR (Free-Range Reduction) propagation, and its intensity fluctuations are almost identical to those of the ASE (Acoustic Emission System) light source (without delay). However, the light returning from the CIR3 port after being combined by the MIOC beam undergoes multiple FRR propagations, resulting in a certain delay in its intensity fluctuations. Since the FRR length and delay time are fixed, there is a phase difference between the intensity fluctuations output from the C2 transmission end and the CIR3 segment.

[0073] To avoid unnecessary interference between the two beams of light at coupler C3, a 90° fusion point is set between couplers C2 and C3, causing the propagation axis to change (from slow axis to fast axis) as the light propagates in this section. At this time, the two beams of light entering coupler C3 have different propagation axes. When they are combined in coupler C3, they only superimpose their light intensities and do not interfere with each other to cause unnecessary additional light intensity fluctuations.

[0074] Furthermore, due to the influence of the lock-in amplifier LIA9, only the specific RIN frequency component equal to the modulation frequency needs to be considered. The coupling ratio of coupler C1 and coupler C25 is 98:2; in coupler C25, the vast majority of the light intensity fluctuations from the ASE have no time delay. Only a small portion of the light passing through the FRR experiences a time delay, and the intensity of this portion is very weak. These intensity fluctuations are reflected at both ports (the output of coupler C2 port and CIR port 3), accompanied by a phase delay of the intensity fluctuations. At CIR port 3, all the light passing through the FRR is delayed, and its intensity is contributed by the superposition of light fields with different period numbers in the FRR.

[0075] The light intensity fluctuation after passing through the fiber optic resonator (FRR) in the unmodulated case can be expressed as follows:

[0076] (1)

[0077] (2)

[0078] (3)

[0079] (4)

[0080] in, It is the coupling coefficient; It is the light transmission time delay in FRR; K It is transmission loss; B It is the superposition value of light intensity fluctuations; D It refers to the range of light intensity fluctuations; b It is the light intensity fluctuation function at the modulation frequency; w and It is the focusing fluctuation frequency and its random phase caused by relative intensity noise RIN; , c and L These are the refractive index of the optical fiber, the speed of light, and the length of the FRR (fiber refractive index).

[0081] Furthermore, it is assumed that the RIN exhibits sinusoidal fluctuations at a specific demodulation frequency; after time delay and superposition of different numbers of cycles, this fluctuation almost maintains its sinusoidal shape in theoretical analysis and simulation.

[0082] Due to the fixed length difference in the light propagation path, different phase differences cause fluctuations in light intensity. Therefore, adjustments are needed to ensure that the phase difference is within acceptable limits. .

[0083] Implementation Method 3

[0084] This embodiment provides a test method for RIN suppression of a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback. The test method uses the RIN suppression method of a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback as described in Embodiment 2. The test method requires specific frequency fluctuation phase difference testing of the constructed optical path.

[0085] To perform on-site phase difference testing, a verification experiment was set up, in which two photodetectors (PD1, PD2) were placed after an idle port at the transmission end of coupler C2 and port 3 of circulator CIR. No modulation signal was applied to the miniature integrated optical waveguide modulator MIOC; instead, a signal generator SG (Signal Generator) was used to generate sine and cosine waves of the same frequency and phase. These two signals were multiplied by PD1 and PD2, respectively, to calculate the phase difference.

[0086] Furthermore, the specific frequency fluctuation phase difference test calculation is as follows:

[0087] (5)

[0088] (6)

[0089] (7)

[0090] in, It is a signal from PD1 or PD2; It is the angular frequency of the signal from the signal generator SG; and and The signal output by SG The signal multiplied by sine and cosine waves; and yes and The signal is processed by a low-pass filter (LPF); by adjusting the signal frequency of SG from a lower frequency (below the intrinsic frequency of the fiber optic loop) to a higher frequency (above the intrinsic frequency of the fiber optic loop), a series of test samples can be obtained. and The phase difference can be calculated as follows: .

[0091] Furthermore, after standardizing a series of samples and calculating their statistical information, the phase difference of light intensity fluctuations at different modulation frequencies can be obtained; the demodulation frequency is gradually adjusted until the demodulation phase difference is π.

[0092] Furthermore, the light source ASE emits white light to drive the resonant optical gyroscope.

[0093] Instruction manual attached Figure 3 The test results for the structure are as shown in the attached instruction manual. Figure 4 As shown, (a), (b), (c), and (d) are respectively based on Figure 3 The phase difference distribution was collected when the demodulation frequency was set to different settings. When the demodulation frequency was set to (b) 800 kHz, the phase difference was mainly concentrated around π (the optimal modulation frequency varies for different optical path structures). This distribution resembles a Gaussian curve distribution because the light intensity fluctuations have random phases and exhibit a probability wave distribution rather than a perfect sine wave distribution. Regardless of whether the frequency increases or decreases, the phase difference distribution deviates from π. This indicates that at 800 kHz, the light intensity fluctuations at the idle port of coupler C2 and the CIR port 3 of the circulator are inversely correlated. The coupling ratio of C3 can be adjusted to make the light intensity fluctuation amplitudes equal, thereby canceling out the light intensity fluctuations at the corresponding frequencies and suppressing RIN.

Claims

1. A broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback, characterized in that, The gyroscope includes a working light source ASE, a circulator CIR, a miniature integrated optical waveguide modulator MIOC, couplers C1 and C2, an optical fiber resonator FRR, a coupler C3, a photodetector PD, a lock-in amplifier LIA, and a low-pass filter LPF. The working light source ASE is connected to port 1 of the circulator CIR, and port 2 of the circulator CIR is connected to the miniature integrated optical waveguide modulator MIOC. The tail end of the miniature integrated optical waveguide modulator MIOC is connected to one end of coupler C1 and one end of coupler C2, respectively. The other end of coupler C1 and the other end of coupler C2 are respectively connected to the fiber resonator FRR to realize multi-turn transmission of light in the fiber resonator FRR. The polarization-maintaining fiber extending from the right transmission end of the coupler C2 is fused at 90 degrees and connected to the No. 3 output end of the circulator CIR, and then connected to one side of the coupler C3. The light intensity signal output by the coupler C3 is detected by the photodetector PD, passed through the lock-in amplifier LIA and the low-pass filter LPF, and then output as the rotation speed value.

2. The broadband light source driven resonant optical gyroscope according to claim 1, characterized in that, The working light source ASE is used to generate a broadband rectangular light field; The circulator CIR is used to transmit the optical field in the forward direction and to split the optical field to the coupler C3 when it is transmitted in the reverse direction. The micro-integrated optical waveguide modulator (MIOC) is used to modulate the frequency and phase of the incident and outgoing light fields. The coupler C1, coupler C2 and fiber resonant cavity FRR together form a resonant angular velocity sensing element, which is an important part of generating the Sagnac effect; The coupler C3 is used to combine the feedback light output from port 3 of the circulator CIR3 with the direct light output from the transmission end of the coupler C2 to cancel out light intensity fluctuations at a specific frequency. The photodetector PD is used to receive the optical signal emitted by the coupler C3 and convert the optical signal into an electrical signal; The lock-in amplifier LIA is used to synchronously demodulate the signal and output signals to the low-pass filter LPF and the micro-integrated optical waveguide modulator MIOC, respectively. The low-pass filter (LPF) is used to filter the synchronously demodulated signal.

3. The broadband light source driven resonant optical gyroscope according to claim 1, characterized in that, The gyroscope can also be driven by white light.

4. A method for suppressing RIN in a broadband light source-driven resonant optical gyroscope based on light intensity fluctuation feedback, characterized in that, The suppression method uses a broadband light source driven by a resonant optical gyroscope based on light intensity fluctuation feedback technology as described in any one of claims 1-3, and the suppression method includes: After the light field required for angular velocity detection is emitted by the working light source ASE, the phase of the light field is modulated and split by the micro integrated optical waveguide modulator MIOC. The split light enters the fiber resonator FRR and propagates clockwise and counterclockwise along the fiber resonator FRR. After multiple turns of transmission via the resonant cavity FRR, one beam of light is output from coupler C2, then enters coupler C3 via 90° fusion splicing, and the other beam of light is combined and returned by the micro integrated optical waveguide modulator MIOC, then output from port 3 of the circulator CIR via port 2, and enters coupler C3. Since the two beams of light entering coupler C3 are not on the same polarization axis, their light intensities are superimposed after passing through coupler C3. The signal light output by coupler C3 is detected by photodetector PD. The photodetector PD converts the light intensity signal into an electrical signal, which is then demodulated by lock-in amplifier LIA. The rotation speed signal carried in the modulation signal is demodulated and stripped out, and then output as the gyroscope rotation speed signal through low-pass filter LPF.

5. The RIN suppression method according to claim 4, characterized in that, Due to the influence of the lock-in amplifier LIA9, the light intensity fluctuation after passing through the fiber resonator FRR is expressed as follows in the unmodulated case: Where α is the coupling coefficient; τ is the light transmission time delay in FRR; K is the transmission loss; B is the superposition value of light intensity fluctuations; D is the range of light intensity fluctuations; b is the light intensity fluctuation function at the modulation frequency; and w and The focusing fluctuation frequency and its random phase are caused by relative intensity noise RIN; n eff c and L are the refractive index of the optical fiber, the speed of light, and the length of the FRR, respectively.

6. The RIN suppression method according to claim 5, characterized in that, Assume that the RIN exhibits a sinusoidal oscillation at a specific demodulation frequency; after time delay and superposition of different numbers of turns, it retains its sinusoidal shape; Due to the fixed length difference of the light propagation path, different phase differences cause light intensity fluctuations, so adjustments are needed to ensure that the phase difference is π.

7. A test method for RIN suppression of a broadband light source-driven resonant optical gyroscope based on light intensity fluctuation feedback, characterized in that, The test method uses the RIN suppression method of a broadband light source driven resonant optical gyroscope based on light intensity fluctuation feedback as described in any one of claims 4-6. The test method requires specific frequency fluctuation phase difference testing of the constructed optical path. Two photodetectors are placed after an idle port at the transmission end of coupler C2 and port 3 of circulator CIR; instead of applying any modulation signal to the miniature integrated optical waveguide modulator MIOC, a sine wave and a cosine wave of the same frequency and phase are generated using signal generator SG; these two signals are respectively coupled to PD1. Multiply by PD2 to calculate the phase difference.

8. The test method according to claim 7, characterized in that, The specific frequency fluctuation phase difference test is calculated as follows: w=2πf (6) Among them, S 1,2-PD (t) is the signal from PD1 or PD2; w is the angular frequency of the signal from signal generator SG; and X 1,2 With Y 1,2 The signal S output by SG 1,2-PD (t) The signal multiplied by a sine and a cosine wave; X 1,2-LPF With Y 1,2-LPF It is X 1,2 With Y 1,2 The signal is processed by a low-pass filter (LPF); by adjusting the signal frequency of SG from a lower frequency to a higher frequency, a series of test samples θ1 and θ2 are obtained; the phase difference is calculated as θ1-θ2.

9. The test method according to claim 8, characterized in that, After standardizing a series of samples and calculating their statistical information, the phase difference of light intensity fluctuations at different modulation frequencies is obtained; the demodulation frequency is gradually adjusted until the demodulation phase difference is π.

10. The test method according to claim 7, characterized in that, The working light source ASE emits white light to drive the resonant optical gyroscope.

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