Resonant fiber gyroscope driven by a wide-spectrum light source using a reflective fiber resonant cavity and its operating method

Abstract

The present invention belongs to the field of optical gyroscopes and discloses a resonant fiber gyroscope driven by a broadband light source using a reflective fiber resonator and an operating method thereof. The working light source ASE is connected to port 1 of a circulator CIR, port 2 of the circulator CIR is connected to the input of a micro-integrated optical chip MIOC, the two outputs of the micro-integrated optical chip MIOC are respectively connected to the two inputs of an optical coupler OC, the two outputs of the optical coupler OC are respectively connected to the two ports of a fiber ring resonator FRR, port 3 of the circulator CIR is connected to the input of a photodetector PD, the output of the photodetector PD is connected to the input of a lock-in amplifier LIA, output 1 of the lock-in amplifier LIA is connected to a modulation pin of the micro-integrated optical chip MIOC, output 2 of the lock-in amplifier LIA is connected to the input of a low-pass filter LPF, and the output of the low-pass filter LPF outputs a resonant fiber gyroscope signal. The present invention can solve the low Q problem of the transmission fiber resonator cavity in a resonant fiber gyroscope driven by a broadband light source and effectively suppress relative intensity noise.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical gyroscopes, and in particular relates to a resonant fiber gyroscope driven by a wide-spectrum light source using a reflective fiber resonant cavity and a working method thereof. Background Art

[0002] A gyroscope is a sensor that accurately determines 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, driven by the demands of major national projects, has placed higher demands on inertial components. While ensuring high precision, they also require features such as miniaturization, low power consumption, high reliability, low cost, and resistance to vibration and shock. The development of gyroscopes directly impacts the key performance of inertial navigation and guidance systems, playing an irreplaceable role in the defense sector.

[0003] Currently, in the field of optical gyroscopes, laser gyros have numerous internal optoelectronic components, making their manufacture difficult and costly. Interferometric fiber gyroscopes (FOGs) exhibit a high degree of precision, which is directly related to the length of the internal fiber loops. High-precision FOGs require loops several kilometers long, making them difficult to miniaturize. In contrast, resonant optical gyros detect angular rate by detecting the resonant frequency difference between oppositely propagating light beams within a cavity, caused by the Sagnac effect. With the resonant cavity as its core sensitive component, the cavities can be as small as sub-millimeter scale, aligning with the trend toward device miniaturization and offering high processing repeatability, device integration capabilities, and sensitivity.

[0004] In existing resonant fiber gyros driven by broadband light sources, the two couplers of the transmission-type fiber resonant cavity suffer from large losses, making it difficult for the resonant cavity to obtain a high Q value. Furthermore, the light intensity ratio between the through-end and the cross-end of the reflective fiber resonant cavity coupler is high, making it difficult to overcome the excessive relative intensity noise. Summary of the Invention

[0005] The present invention provides a resonant fiber gyroscope driven by a wide-spectrum light source using a reflective fiber resonant cavity and a working method thereof, so as to solve the low Q value problem of the transmissive fiber resonant cavity of the resonant fiber gyroscope driven by the wide-spectrum light source in the prior art, effectively suppress relative intensity noise, and improve the sensitivity of the resonant fiber gyroscope driven by the wide-spectrum light source.

[0006] The present invention is achieved through the following technical solutions:

[0007] A resonant fiber gyroscope driven by a broad-spectrum light source of a reflective fiber resonant cavity, comprising a working light source ASE, a circulator CIR, a micro-integrated optical chip MIOC, an optical coupler OC, a fiber ring resonator FRR, a photodetector PD, a lock-in amplifier LIA, and a low-pass filter LPF;

[0008] The working light source ASE is connected to port 1 of the circulator CIR, port 2 of the circulator CIR is connected to the input end of the micro-integrated optical chip MIOC, the two output ends of the micro-integrated optical chip MIOC are respectively connected to the two input ends of the optical coupler OC, and the two output ends of the optical coupler OC are respectively connected to the two ports of the fiber ring resonator FRR.

[0009] The port 3 of the circulator CIR is connected to the input end of the photodetector PD, and the output end of the photodetector PD is connected to the input end of the lock-in amplifier LIA.

[0010] Output terminal 1 of the lock-in amplifier LIA is connected to the modulation pin of the micro-integrated optical chip MIOC, output terminal 2 of the lock-in amplifier LIA is connected to the input terminal of the low-pass filter LPF, and the output terminal of the low-pass filter LPF outputs the resonant fiber gyroscope signal.

[0011] Furthermore, the working light source ASE is used to output a wide-spectrum laser;

[0012] The working light source ASE is used to output a wide-spectrum light field;

[0013] The circulator CIR is used to transmit the incident wave at any port thereof to the next port in a direction determined by the static bias magnetic field;

[0014] The micro-integrated optical chip MIOC is used to polarize, split and modulate the input light wave;

[0015] The optical coupler OC is used to split or combine optical powers of the same wavelength;

[0016] The fiber ring resonator FRR is used to control the light wave to propagate periodically in a clockwise or counterclockwise direction;

[0017] The photodetector PD is used to convert the optical signal into an electrical signal;

[0018] The lock-in amplifier LIA is used to synchronously demodulate the signal and output the signal to the low-pass filter LPF and the micro-integrated optical chip MIOC respectively;

[0019] The low-pass filter LPF is used to filter the synchronously demodulated signal.

[0020] A method for operating a resonant fiber gyroscope driven by a broad-spectrum light source using a reflective fiber resonant cavity, the method comprising:

[0021] The broad spectrum laser output by the working light source ASE passes through the clockwise circulator CIR and then enters the micro integrated optical chip MIOC;

[0022] The broadband laser passes through the micro-integrated optical chip MIOC and the optical coupler OC into the fiber ring resonator FRR in clockwise and counterclockwise directions respectively;

[0023] The fiber ring resonator (FRR) controls the light wave to propagate several circles in a clockwise or counterclockwise direction periodically before being output. After passing through the optical coupler (OC), the interference light wave signal at the collection port of the micro-integrated optical chip (MIOC) carries the Sagnac phase shift and passes through the circulator (CIR) before being detected by the photodetector (PD).

[0024] The light waves between one output port of the micro-integrated optical chip MIOC and the coupler OC pass through the first 90° fusion point, and the light waves in the fiber ring resonator FRR periodically pass through the second 90° fusion point to achieve polarization separation of the light waves;

[0025] The photodetector PD converts the optical signal into an electrical signal, which is then synchronously demodulated by the lock-in amplifier LIA. The output of the lock-in amplifier LIA passes through a low-pass filter LPF and is used as the gyroscope output.

[0026] The demodulated signal is synchronously fed back to the modulation pin of the micro-integrated optical chip MIOC through the lock-in amplifier LIA to achieve closed-loop control.

[0027] Furthermore, the polarization state of the light wave passing through the first 90° fusion point is perpendicular to the axis of the micro-integrated optical chip MIOC. The polarization extinction ratio of the micro-integrated optical chip MIOC is as high as 70dB. The light wave passing through the micro-integrated optical chip MIOC and the straight-through end of the coupler OC and then returning is completely lost and does not reach the photodetector PD.

[0028] The second 90° fusion point is inside the fiber ring resonator (FRR). After the light wave propagates an odd number of circles in the fiber ring resonator (FRR), the polarization axis of the light wave is aligned with the pass axis of the micro-integrated optical chip (MIOC), and the returning light wave can reach the photodetector (PD).

[0029] Furthermore, the expression of the light wave field received by the photodetector PD is:

[0030] E PD =E b +E r (1)

[0031] Among them, E b is the light wave that passes through the straight port of the coupler OC but does not enter the fiber ring resonator FRR, E rThe light wave passing through the intersection of the coupler OC and the fiber ring resonator FRR, the light wave returning through the micro-integrated optical chip MIOC and the straight-through end of the coupler OC is completely lost and does not reach the photodetector PD, so E b Equal to 0,E r Given by the following formula:

[0032]

[0033] Among them, E CW (n) represents the light field propagating n circles in the CW direction of the fiber ring resonator FRR, E CCW (n) represents the light field that propagates n circles in the CCW direction of the fiber ring resonator FRR.

[0034] Furthermore, according to formula (2), the light wave reaching the photodetector PD is divided into two parts. One part is the CW light field passing through the fiber ring resonator FRR, which is expressed as,

[0035]

[0036] The other part is the CCW light field passing through the fiber ring resonator FRR, which is expressed as:

[0037]

[0038] Among them, E cross_cw_n represents the light field propagating n circles in the CW direction of the fiber ring resonator FRR, E cross_ccw_n It represents the light field propagating n circles in the CCW direction of the fiber ring resonator FRR, which is expanded as follows:

[0039]

[0040] Where E0 represents the amplitude of the light field of the light source, α cir represents the power loss coefficient of the circulator CIR, γ represents the power loss coefficient of the micro-integrated optical chip MIOC, γ represents the insertion loss of the coupler OC, and k c Indicates the power coupling coefficient of the coupler OC cross-end, α L represents the loss of the fiber ring resonator FRR, represents the optical field transmission loss of a light wave propagating one circle in the fiber ring resonator FRR, f represents the center frequency of the working light source ASE; FSR cw 、FSR ccw represent the CW and CCW free spectral widths of the fiber ring resonator FRR, respectively;

[0041] Furthermore, when the fiber ring resonator FRR rotates,

[0042] FSRcw =FSR+f sag / (2m)(7)

[0043] FSR ccw =FSR-f sag / (2m)(8)

[0044] Where FSR represents the free spectrum width of the fiber ring resonator FRR when there is no rotation, m = f / FSR represents the mth longitudinal mode of the fiber ring resonator FRR corresponding to the center frequency of the working light source ASE, and f sag =DΩ / (n eff λ) represents the sagnac frequency splitting, D is the diameter of the fiber ring resonator FRR, Ω is the rotation angular velocity, and n eff is the effective refractive index of the fiber ring resonator FRR, and λ is the central wavelength of the working light source ASE.

[0045] Furthermore, since the cavity length of the fiber ring resonator FRR is much longer than the coherence length of the working light source ASE, only light waves with the same number of turns propagating in the fiber ring resonator FRR will interfere, so the light intensity I detected by the photodetector PD is pd It can be expressed as:

[0046]

[0047] Furthermore, the optical coupler OC, the circulator CIR, the working light source ASE, the fiber ring resonator FRR, the micro-integrated optical chip MIOC and the photodetector PD are all components with polarization-maintaining characteristics, and have the same working wavelength.

[0048] Furthermore, the ultimate accuracy of the resonant fiber gyroscope driven by a broadband light source is expressed as:

[0049]

[0050] Where D is the diameter of the fiber ring resonator FRR, P pd is the optical power received by the photodetector PD, R PD is the responsivity of the photodetector PD, and e is the electron charge. From the formula, it can be seen that the limit accuracy is directly related to α L Fiber loss, k c The power coupling coefficient at the OC cross-end of the coupler is inversely proportional to the quality factor of the Q resonant cavity.

[0051] The beneficial effects of the present invention are:

[0052] The present invention uses a broadband ASE laser as its working light source and a double-90° fused reflective fiber ring resonator as its resonant cavity, which can improve the sensitivity of a resonant gyroscope driven by a broadband light source. Compared with a transmissive ring resonator, a reflective fiber ring resonator can eliminate one coupler splice, thereby improving the resonator's quality factor. The light wave intensity at the through-end of the coupler in the reflective resonant cavity is much greater than that at the cross-end, causing the light wave signal received by the photodetector to be overwhelmed by noise. The double-90° fusion can effectively reduce relative intensity noise under the coupler's high polarization extinction ratio. This shows that the present invention improves the gyroscope's sensitivity while also improving its signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a structural schematic diagram of the present invention.

[0054] Figure 2 It is a schematic diagram of the sensitivity increase value under different loss parameters of the present invention.

[0055] Figure 3 It is the transmission curve and relative intensity noise spectrum diagram of the transmission resonant cavity with and without double 90° fusion.

[0056] Figure 4 This is a relative intensity noise spectrum diagram under different coupler polarization extinction ratio parameters of the present invention.

[0057] Figure 5 This is a relationship diagram of the angle random walk under different polarization extinction ratio parameters of the coupler of the present invention as the coupling coefficient changes. DETAILED DESCRIPTION

[0058] In the following description, specific details such as specific system structures and technologies are provided for illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obstructing the description of the present application with unnecessary details.

[0059] It will be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0060] It should also be understood that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this 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.

[0061] The following is attached to this application specification Figure 1-5 , clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of this application.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0063] Implementation Method 1

[0064] This embodiment provides a resonant fiber gyroscope driven by a broadband light source using a reflective fiber resonator. The resonant fiber gyroscope driven by the broadband light source includes a working light source ASE, a circulator CIR, a micro-integrated optical chip MIOC, an optical coupler OC, a fiber ring resonator FRR, a photodetector PD, a lock-in amplifier LIA, and a low-pass filter LPF.

[0065] The working light source ASE is connected to port 1 of the circulator CIR, port 2 of the circulator CIR is connected to the input end of the micro-integrated optical chip MIOC, the two output ends of the micro-integrated optical chip MIOC are respectively connected to the two input ends of the optical coupler OC, and the two output ends of the optical coupler OC are respectively connected to the two ports of the fiber ring resonator FRR.

[0066] The port 3 of the circulator CIR is connected to the input end of the photodetector PD, and the output end of the photodetector PD is connected to the input end of the lock-in amplifier LIA.

[0067] Output terminal 1 of the lock-in amplifier LIA is connected to the modulation pin of the micro-integrated optical chip MIOC, output terminal 2 of the lock-in amplifier LIA is connected to the input terminal of the low-pass filter LPF, and the output terminal of the low-pass filter LPF outputs the resonant fiber gyroscope signal.

[0068] Furthermore, the working light source ASE is used to output a wide-spectrum light field;

[0069] The circulator CIR is used to transmit the incident wave at any port thereof to the next port in a direction determined by the static bias magnetic field;

[0070] The micro-integrated optical chip MIOC is used to polarize, split and modulate the input light wave;

[0071] The optical coupler OC is used to split or combine optical powers of the same wavelength;

[0072] The fiber ring resonator FRR is used to control the light wave to propagate periodically in a clockwise or counterclockwise direction;

[0073] The photodetector PD is used to convert the optical signal into an electrical signal;

[0074] The lock-in amplifier LIA is used to synchronously demodulate the signal and output the signal to the low-pass filter LPF and the micro-integrated optical chip MIOC respectively;

[0075] The low-pass filter LPF is used to filter the synchronously demodulated signal.

[0076] Specifically, the optical coupler OC, circulator CIR, working light source ASE, fiber ring resonator FRR, micro integrated optical chip MIOC and photodetector PD are all components with polarization maintaining characteristics, and have the same operating wavelength, for example, 1550 nm.

[0077] The working light source ASE is a broadband laser with a spectral line width greater than 30 nm and a power greater than 10 mW.

[0078] The circulator CIR is a three-port optical fiber clockwise circulator.

[0079] The fiber ring resonator FRR has a basic reflective structure, a diameter of 10 centimeters, and a length of 110 meters.

[0080] Implementation Method 2

[0081] This embodiment provides a method for operating a resonant fiber gyroscope driven by a broadband light source using a reflective fiber resonant cavity. This method uses the resonant fiber gyroscope driven by a broadband light source using a reflective fiber resonant cavity as described in the first embodiment. Specifically,

[0082] The broad-spectrum laser output by the working light source ASE passes through the clockwise circulator CIR and then enters the micro-integrated optical chip MIOC. The micro-integrated optical chip MIOC is used to polarize, split, and modulate the input light wave.

[0083] The broadband laser passes through the micro-integrated optical chip MIOC and the optical coupler OC into the fiber ring resonator FRR in clockwise and counterclockwise directions respectively;

[0084] The fiber ring resonator (FRR) controls the lightwave to propagate several cycles clockwise or counterclockwise periodically before outputting it. The lightwaves then interfere with each other at the converging port of the micro-integrated optical chip (MIOC) via an optical coupler (OC). The micro-integrated optical chip (MIOC) combines the clockwise and counterclockwise outputs of the FRR. The interfering lightwave signal carrying the Sagnac phase shift passes through the circulator (CIR) and is detected by the photodetector (PD).

[0085] The light wave between an output port of the micro-integrated optical chip MIOC and the coupler OC passes through the first 90° fusion point, changing the linear polarization transmission axis of the input light in one direction and the output light in the other direction of the fiber ring resonator FRR. The light wave in the fiber ring resonator FRR periodically passes through the second 90° fusion point, so that the polarization axis of the light wave containing the Sagnac phase shift part is aligned with the working axis of the micro-integrated optical chip MIOC, achieving light wave polarization separation.

[0086] The photodetector PD converts the optical signal into an electrical signal, which is then synchronously demodulated by the lock-in amplifier LIA. The output of the lock-in amplifier LIA passes through a low-pass filter LPF and is used as the gyroscope output.

[0087] The demodulated signal is synchronously fed back to the modulation pin of the micro-integrated optical chip MIOC through the lock-in amplifier LIA to achieve closed-loop control.

[0088] Furthermore, the polarization state of the light wave passing through the first 90° fusion point is perpendicular to the axis of the micro-integrated optical chip MIOC. The polarization extinction ratio of the micro-integrated optical chip MIOC is as high as 70dB. The light wave passing through the micro-integrated optical chip MIOC and the straight-through end of the coupler OC and then returning is completely lost and does not reach the photodetector PD.

[0089] The second 90° fusion point is inside the fiber ring resonator (FRR). After the light wave propagates an odd number of circles in the fiber ring resonator (FRR), the polarization axis of the light wave is aligned with the pass axis of the micro-integrated optical chip (MIOC), and the returning light wave can reach the photodetector (PD).

[0090] Furthermore, the ultimate accuracy of the resonant fiber gyroscope driven by a broadband light source is expressed as:

[0091]

[0092] Where D is the diameter of the fiber ring resonator FRR, P pd is the optical power received by the photodetector PD, R PDis the responsivity of the photodetector PD, and e is the electron charge. From the formula, it can be seen that the limit accuracy is directly related to α L Fiber loss, k c The power coupling coefficient at the OC cross-end of the coupler is inversely proportional to the quality factor of the Q resonant cavity. The reflective resonant cavity uses one less coupler than the transmissive resonator, so it has smaller cavity loss and higher quality factor. Therefore, the sensitivity increase SEF of the reflective resonant cavity and the transmissive resonator is as follows: Figure 2 shown.

[0093] Furthermore, the expression of the light wave field received by the photodetector PD after the light wave passes through the two 90° fusion points is:

[0094] E PD =E b +E r (1)

[0095] Among them, E b is the light wave that passes through the straight port of the coupler OC but does not enter the fiber ring resonator FRR, E r The light wave passing through the intersection of the coupler OC and the fiber ring resonator FRR, the light wave returning through the micro-integrated optical chip MIOC and the straight-through end of the coupler OC is completely lost and does not reach the photodetector PD, so E b Equal to 0,E r Given by the following formula:

[0096]

[0097] Among them, E CW (n) represents the light field propagating n circles in the CW direction of the fiber ring resonator FRR, E CCW (n) represents the light field that propagates n circles in the CCW direction of the fiber ring resonator FRR.

[0098] Furthermore, according to formula (2), the light wave reaching the photodetector PD is divided into two parts. One part is the CW light field passing through the fiber ring resonator FRR, which is expressed as,

[0099]

[0100] The other part is the CCW light field passing through the fiber ring resonator FRR, which is expressed as:

[0101]

[0102] Among them, E cross_cw_n represents the light field propagating n circles in the CW direction of the fiber ring resonator FRR, E cross_ccw_nIt represents the light field propagating n circles in the CCW direction of the fiber ring resonator FRR, which is expanded as follows:

[0103]

[0104] Where E0 represents the amplitude of the light field of the light source, α cir represents the power loss coefficient of the circulator CIR, γ represents the power loss coefficient of the micro-integrated optical chip MIOC, γ represents the insertion loss of the coupler OC, and k c Indicates the power coupling coefficient of the coupler OC cross-end, α L represents the loss of the fiber ring resonator FRR, represents the optical field transmission loss of a light wave propagating one circle in the fiber ring resonator FRR, f represents the center frequency of the working light source ASE; FSR cw 、FSR ccw represent the CW and CCW free spectral widths of the fiber ring resonator FRR, respectively;

[0105] Furthermore, when the fiber ring resonator FRR rotates,

[0106] FSR cw =FSR+f sag / (2m)(7)

[0107] FSR ccw =FSR-f sag / (2m)(8)

[0108] Where FSR represents the free spectrum width of the fiber ring resonator FRR when there is no rotation, m = f / FSR represents the mth longitudinal mode of the fiber ring resonator FRR corresponding to the center frequency of the working light source ASE, and f sag =DΩ / (n eff λ) represents the sagnac frequency splitting, D is the diameter of the fiber ring resonator FRR, Ω is the rotation angular velocity, and n eff is the effective refractive index of the fiber ring resonator FRR, and λ is the central wavelength of the working light source ASE.

[0109] Furthermore, since the cavity length of the fiber ring resonator FRR is much longer than the coherence length of the working light source ASE, only light waves with the same number of turns propagating in the fiber ring resonator FRR will interfere, so the light intensity I detected by the photodetector PD is pd It can be expressed as:

[0110]

[0111] Furthermore, the optical coupler OC, the circulator CIR, the working light source ASE, the fiber ring resonator FRR, the micro-integrated optical chip MIOC and the photodetector PD are all components with polarization-maintaining characteristics, and have the same working wavelength.

[0112] It can be seen from formula (7) that only the light waves that rotate an odd number of circles around the fiber ring resonator FRR can be detected by the photodetector PD. Compared with the transmission resonant cavity, its transmission spectrum has a downward transmission valley at FSR / 2, and its relative noise spectrum period is reduced by half. Compared with the transmission resonant cavity without polarization separation method, its relative noise is reduced and the detection accuracy is improved, as shown in the following example: Figure 3 shown.

Claims

1. A resonant fiber gyroscope driven by a broadband light source using a reflective fiber resonant cavity, characterized in that: The resonant fiber gyroscope driven by the broadband light source includes a working light source ASE, a circulator CIR, a micro integrated optical chip MIOC, an optical coupler OC, a fiber ring resonator FRR, a photodetector PD, a lock-in amplifier LIA and a low-pass filter LPF; The working light source ASE is connected to port No. 1 of the circulator CIR, port No. 2 of the circulator CIR is connected to the input end of the micro-integrated optical chip MIOC, an output port of the micro-integrated optical chip MIOC is connected to an input end of the optical coupler OC via a first 90° fusion point, another output end of the micro-integrated optical chip MIOC is connected to another input end of the optical coupler OC, an output end of the optical coupler OC is connected to a port of the fiber ring resonator FRR, and the other output end of the optical coupler OC is connected to another port of the fiber ring resonator FRR via a second 90° fusion point; The port 3 of the circulator CIR is connected to the input end of the photodetector PD, and the output end of the photodetector PD is connected to the input end of the lock-in amplifier LIA. Output terminal 1 of the lock-in amplifier LIA is connected to the modulation pin of the micro-integrated optical chip MIOC, output terminal 2 of the lock-in amplifier LIA is connected to the input terminal of the low-pass filter LPF, and the output terminal of the low-pass filter LPF outputs the resonant fiber gyroscope signal.

2. The resonant fiber gyroscope driven by a broadband light source according to claim 1, characterized in that: The working light source ASE is used to output a wide-spectrum light field; The circulator CIR is used to transmit the incident wave from any port thereof to the next port in a direction determined by the static bias magnetic field; The micro-integrated optical chip MIOC is used to polarize, split and modulate the input light wave; The optical coupler OC is used to split or combine optical powers of the same wavelength; The fiber ring resonator FRR is used to control the light wave to propagate periodically in a clockwise or counterclockwise direction; The photodetector PD is used to convert the optical signal into an electrical signal; The lock-in amplifier LIA is used to synchronously demodulate the signal and output the signal to the low-pass filter LPF and the micro integrated optical chip MIOC respectively; The low-pass filter LPF is used to filter the synchronously demodulated signal.

3. The operating method of a resonant fiber gyroscope driven by a broadband light source using a reflective fiber resonant cavity according to claim 1 or 2, characterized in that: The working method is specifically as follows: The broad spectrum laser output by the working light source ASE passes through the clockwise circulator CIR and then enters the micro integrated optical chip MIOC; The broadband laser passes through the micro-integrated optical chip MIOC and the optical coupler OC into the fiber ring resonator FRR in clockwise and counterclockwise directions respectively; The fiber ring resonator (FRR) controls the light wave to propagate several circles in a clockwise or counterclockwise direction periodically before being output. After passing through the optical coupler (OC), the interference light wave signal at the collection port of the micro-integrated optical chip (MIOC) carries the Sagnac phase shift and passes through the circulator (CIR) before being detected by the photodetector (PD). The light wave between one output port of the micro-integrated optical chip MIOC and the coupler OC passes through the first 90° fusion point, and the light wave in the fiber ring resonator FRR periodically passes through the second 90° fusion point to achieve polarization separation of the light wave; The photodetector PD converts the optical signal into an electrical signal, which is then synchronously demodulated by the lock-in amplifier LIA. The output of the lock-in amplifier LIA passes through a low-pass filter LPF and is used as the gyroscope output. The synchronous demodulated signal is fed back to the modulation pin of the micro-integrated optical chip MIOC through the lock-in amplifier LIA to achieve closed-loop control; The polarization state of the light wave passing through the first 90° fusion point is perpendicular to the axis of the micro-integrated optical chip MIOC. The polarization extinction ratio of the micro-integrated optical chip MIOC is as high as 70dB. The light wave passing through the micro-integrated optical chip MIOC and the straight-through end of the coupler OC and then returning is completely lost and does not reach the photodetector PD. The second 90° fusion point is inside the fiber ring resonator (FRR). After the light wave propagates an odd number of circles in the fiber ring resonator (FRR), the polarization axis of the light wave is aligned with the pass axis of the micro-integrated optical chip (MIOC), and the returning light wave can reach the photodetector (PD).

4. The working method according to claim 3, characterized in that: The expression of the light wave field received by the photodetector PD is: （1） in, is the light wave that passes through the straight port of the coupler OC but does not enter the fiber ring resonator FRR, The light waves passing through the intersection of the coupler OC and the fiber ring resonator FRR, the light waves returning through the micro-integrated optical chip MIOC and the straight-through end of the coupler OC are completely lost and will not reach the photodetector PD, so is equal to 0, Given by the following formula: （2） in, E CW ( n ) represents the CW propagation in the fiber ring resonator FRR Circle of light field, E CCW ( n ) represents the CCW propagation in the fiber ring resonator FRR Circle of light field.

5. The working method according to claim 4, characterized in that: According to formula (2), the light wave reaching the photodetector PD is divided into two parts. One part is the CW light field passing through the fiber ring resonator FRR, which is expressed as: （3） The other part is the CCW light field passing through the fiber ring resonator FRR, which is expressed as: （4） in, Indicates the CW propagation in the fiber ring resonator FRR Circle of light field, Indicates CCW propagation in the fiber ring resonator FRR The light field of the circle is expanded as follows: （5） （6） Where, represents the amplitude of the light field of the light source, represents the power loss coefficient of the circulator CIR, represents the power loss coefficient of the micro-integrated optical chip MIOC, represents the insertion loss of the coupler OC, Indicates the power coupling coefficient of the coupler OC cross-end, represents the loss of the fiber ring resonator FRR, It represents the optical field transmission loss when the light wave propagates one circle in the fiber ring resonator FRR. Indicates the center frequency of the working light source ASE; 、 represent the CW and CCW free spectral widths of the fiber ring resonator FRR, respectively.

6. The working method according to claim 5, characterized in that: When the fiber ring resonator FRR rotates, （7） （8） Where FSR is the free spectral width of the fiber ring resonator FRR when there is no rotation, The center frequency of the working light source ASE corresponds to the first order of the fiber ring resonator FRR. A vertical model, represents the sagnac frequency splitting, D is the diameter of the fiber ring resonator FRR, is the angular velocity of rotation, is the effective refractive index of the fiber ring resonator FRR, is the central wavelength of the working light source ASE.

7. The working method according to claim 6, characterized in that: Since the cavity length of the fiber ring resonator FRR is much longer than the coherence length of the working light source ASE, only light waves with the same number of turns propagating in the fiber ring resonator FRR will interfere, so the light intensity detected by the photodetector PD is It can be expressed as: （9）。 8. The working method according to claim 4, characterized in that: The optical coupler OC, the circulator CIR, the working light source ASE, the fiber ring resonator FRR, the micro-integrated optical chip MIOC and the photodetector PD are all components with polarization-maintaining characteristics and have the same working wavelength.

9. The working method according to claim 4, characterized in that: The ultimate accuracy of a resonant fiber gyroscope driven by a broadband light source is expressed as: （10） Where D is the diameter of the fiber ring resonator FRR, is the optical power received by the photodetector PD, is the responsivity of the photodetector PD, is the electron charge; from the formula, the limiting accuracy is directly related to Fiber loss, The power coupling coefficient at the OC cross-end of the coupler is inversely proportional to the quality factor Q of the resonant cavity.

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