A singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking

Abstract

The present invention provides a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking, wherein the DFB is connected to the No. 1 port of CIR1, the No. 2 port of CIR1 is connected to the No. 1 port of CIR2, the No. 3 port of CIR2 is connected to the No. 3 port of CIR1 through FPF1, the No. 2 port of CIR2 is connected to the No. 1 port of WGMR, the No. 2 port of CIR1 is connected to the No. 1 port of CIR3 through AOM, the No. 2 port of CIR3 is connected to the No. 2 port of WGMR, the No. 3 port of CIR2 is connected to PD through FPF2, the No. 3 port of CIR3 is connected to PD through FPF3, and the PD is connected to EC. The present invention can effectively suppress the laser noise near the singular point and reduce the cost and volume of the gyroscope.

Description

Technical Field

[0001] The invention belongs to the field of optical gyroscopes, and specifically relates to a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking. Background Art

[0002] Driven by consumer smart devices, micro-drones and micro-satellites, low-cost, low-power, high-precision and miniaturized gyroscopes have received widespread attention. Since the emergence of integrated optical devices for communications, micro-optical gyroscopes with small-sized ring resonators (even in chip-based form) have been identified as the preferred solution. The development level of gyroscopes directly affects the key performance of inertial navigation and guidance systems, and plays an irreplaceable role in the field of national defense.

[0003] At present, the resonant cavity as the core sensitive element can achieve high quality factor (Q value) and micro-nano scale, but the accuracy of micro-optical gyroscope is still not ideal. Compared with the mature ring laser gyroscope and interferometric fiber gyroscope, the micro-optical gyroscope is still in the laboratory research stage. Therefore, many new schemes to improve the performance of micro-optical gyroscope are being widely studied. Singular points are generated in non-Hermitian Hamiltonians and are degenerate points of two or more eigenvalues ​​and corresponding eigenstates. On various non-Hermitian platforms, the abnormal optical phenomena near the singular points have been theoretically and experimentally demonstrated, especially the enhancement of weak perturbations by eigenfrequency splitting. In the field of angular velocity sensing, the sensitivity of the gyroscope can be greatly improved by controlling the non-Hermitian system of the singular point. This method can use a micron-scale resonant cavity as its core sensitive component, which conforms to the development trend of device miniaturization and has great potential in improving sensitivity and signal-to-noise ratio.

[0004] However, new research shows that due to the non-orthogonality of the modes, the laser linewidth broadening caused by excessive quantum noise limits the improvement of angular velocity sensing sensitivity. The linewidth broadening factor, known as the Petermann factor, precisely offsets the signal enhancement factor, resulting in no improvement in the signal-to-noise ratio. This is similar to the fast-light enhanced laser gyroscope, where the enhanced frequency splitting is also offset by the laser linewidth broadening. In addition, in order to achieve complex electrical feedback frequency locking, these micro-light gyroscope schemes require large-size narrow-linewidth tunable lasers and servo control systems, which hinders their development towards low cost, low power consumption and miniaturization. Summary of the invention

[0005] The purpose of the present invention is to provide a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking, which can effectively suppress the noise error caused by the Petermann linewidth enhancement factor, improve the sensitivity of the Brillouin micro-optical gyroscope, and reduce the required cost and volume.

[0006] The objective of the present invention is achieved in that the present invention comprises: a working light source DFB, a circulator CIR1, a circulator CIR2, a circulator CIR3, a micro-resonant cavity WGMR, a Fabry-Perot resonant cavity filter FPF1, a Fabry-Perot resonant cavity filter FPF2, a Fabry-Perot resonant cavity filter FPF3, an acousto-optic modulator AOM, a photodetector PD and a time detection circuit EC; the working light source DFB is connected to port No. 1 of the circulator CIR1, the port No. 2 of the circulator CIR1 is connected to port No. 1 of the circulator CIR2, the port No. 3 of the circulator CIR1 is connected to the circulator CIR2 through the Fabry-Perot resonant cavity filter FPF1, and the port No. 4 of the circulator CIR2 is connected to the circulator CIR3 through the Fabry-Perot resonant cavity filter FPF3. Port No. 3 of the circulator CIR1 is connected, port No. 2 of the circulator CIR2 is connected to port No. 1 of the micro-resonance cavity WGMR, port No. 2 of the circulator CIR1 is connected to port No. 1 of the circulator CIR3 through an acousto-optic modulator AOM, port No. 2 of the circulator CIR3 is connected to port No. 2 of the micro-resonance cavity WGMR, port No. 3 of the circulator CIR2 is connected to the photodetector PD through a Fabry-Perot resonant cavity filter FPF2, port No. 3 of the circulator CIR3 is connected to the photodetector PD through a Fabry-Perot resonant cavity filter FPF3, and the photodetector PD is connected to a time detection circuit EC.

[0007] A detection method for a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking comprises the following steps:

[0008] Step 1: The single longitudinal mode laser output by the working light source DFB is divided into two paths after passing through the counterclockwise circulator CIR1. One path enters the port 1 of the circulator CIR2, and the other path enters the port 1 of the circulator CIR3 after the frequency is shifted by the acousto-optic modulator AOM so that the system reaches the singular point.

[0009] Step 2: Port 2 of the circulator CIR2 outputs a light wave to port 1 of the micro-resonator WGMR. The light wave is excited inside the micro-resonator WGMR to form Brillouin scattering SBS1 and Rayleigh scattering RBS1 in opposite directions, and passes through port 1 of the micro-resonator WGMR to port 2 of the circulator CIR2; the light waves SBS1 and RBS1 are output from port 3 of the circulator CIR2 and divided into two paths, one of which passes through the Fabry-Perot resonator filter FPF1 to filter out the Brillouin scattering SBS1, and the remaining Rayleigh scattering RBS1 is self-injected back into the working light source DFB through port 3 of the circulator CIR1, and the other path passes through the Fabry-Perot resonator filter FPF2 to filter out the Rayleigh scattering RBS1, and the remaining Brillouin scattering SBS1;

[0010] Step 3: Port 2 of the circulator CIR3 outputs a light wave to port 2 of the micro-resonator WGMR. The light wave is excited inside the micro-resonator WGMR to form Brillouin scattering SBS2 and Rayleigh scattering RBS2 in opposite directions, and passes through port 2 of the micro-resonator WGMR to port 2 of the circulator CIR3; the light waves SBS2 and RBS2 are output from port 3 of the circulator CIR3 and pass through the Fabry-Perot resonator filter FPF3 to filter out the Rayleigh scattering RBS2, leaving the Brillouin scattering SBS2;

[0011] Step 4: The remaining Brillouin scattering SBS1 after passing through the Fabry-Perot resonant cavity filter FPF2 in step 2 and the remaining Brillouin scattering SBS2 after passing through the Fabry-Perot resonant cavity filter FPF3 in step 3 are combined and coupled to generate a beat signal. The frequency period of the beat signal is detected by the time detection circuit EC to calculate the actual rotation speed of the gyroscope.

[0012] Furthermore, in step 1, the frequency is shifted by the acousto-optic modulator AOM to make the system reach a singular point, resulting in enhanced sensitivity. The expression of the change of the beat signal frequency and the proportional factor is:

[0013]

[0014]

[0015] Where Δf s is the Brillouin scattering beat frequency signal, γ is the photon attenuation rate, Γ is the Brillouin gain bandwidth, Δf p is the pump light frequency difference, Δf sag is the frequency change caused by the Sagnac effect, Δf c is the critical pump frequency difference of the system at the singular point, S E is the proportional factor, D and n are the cavity diameter and refractive index respectively, and λ is the wavelength of light.

[0016] Furthermore, in step 2, the Rayleigh scattering RBS1 is self-injected back into the working light source DFB through port 3 of the circulator CIR1 to perform self-injection frequency locking as follows:

[0017]

[0018] in, is the difference between the initial frequency of the laser and the resonant frequency of the resonant cavity, is the difference between the steady-state output frequency and the resonant frequency of the resonant cavity, f 0 , f m and f s are the laser initial frequency, the resonant cavity resonant frequency and the steady-state output frequency, respectively. mis the half-width of the resonant cavity, K is the feedback coefficient, α is the coupling coefficient of the resonant cavity, β is the dimensionless coupling ratio between the counter-propagating modes (directly related to the mode splitting), is the phase delay.

[0019] Furthermore, the Rayleigh scattering RBS1 is injected back into the working light source DFB through port 3 of the circulator CIR1 to narrow the line width. The expression is:

[0020]

[0021] Among them, Δν 0 and Δν p are the laser line width before and after narrowing, Q d and Q m are the Q values ​​of the laser resonant cavity and the gyro resonant cavity, T m is the amplitude of the gyro resonant cavity transfer function, and η is the linewidth enhancement factor. The enhancement of the Sagnac effect near the singular point will be limited by the linewidth broadening of the Petermann factor. Therefore, after introducing the self-injection locking linewidth narrowing, the laser noise and beat frequency output signals are,

[0022]

[0023]

[0024] Among them, S v is the laser noise, is the Petermann linewidth enhancement factor, S v0 is the non-increasing noise far from the singular point, R v =Δv 0 / Δv p is the line width narrowing ratio, Δf SI is the beat frequency output signal, and Ω is the angular velocity of the gyroscope.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: the working light source of the present invention adopts a small DFB laser, and the resonant cavity adopts a whispering gallery mode micro-disk resonant cavity, which can simplify the structure of the resonant optical gyroscope, reduce the volume, and reduce the cost; through the self-injection locking technology, the laser line width can be narrowed, the noise impact caused by the Petermann line width enhancement factor can be reduced, and the sensitivity of the gyroscope can be effectively improved; the frequency of the beat signal can be directly detected, which can greatly reduce the impact of optical noise such as polarization fluctuation noise. It can be seen that the present invention can reduce the volume and cost of the gyroscope while improving the sensitivity of the gyroscope. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the present invention.

[0027] Figure 2 The invention is based on the influence of the singular point signal enhancement factor on the beat signal frequency and the proportional factor.

[0028] Figure 3 It is the self-injection locking curve of the present invention.

[0029] Figure 4 It is a schematic diagram of line width narrowing under different parameters of the present invention.

[0030] Figure 5 This is the effect of the self-injection locking of the present invention on noise and output beat frequency signal. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] A high-sensitivity resonant micro-optical gyroscope based on self-injection frequency locking, the singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking comprises: a working light source DFB, a circulator CIR1, a circulator CIR2, a circulator CIR3, a micro-resonant cavity WGMR, a Fabry-Perot resonant cavity filter FPF1, a Fabry-Perot resonant cavity filter FPF2, a Fabry-Perot resonant cavity filter FPF3, an acousto-optic modulator AOM, a photodetector PD and a time detection circuit EC,

[0034] The working light source DFB is connected to port 1 of the circulator CIR1, port 2 of the circulator CIR1 is connected to port 1 of the circulator CIR2, port 3 of the circulator CIR1 is connected to port 3 of the circulator CIR1 through a Fabry-Perot resonant cavity filter FPF1, port 2 of the circulator CIR2 is connected to port 1 of the micro-resonant cavity WGMR,

[0035] Port No. 2 of the circulator CIR1 is connected to Port No. 1 of the circulator CIR3 through an acousto-optic modulator AOM, and Port No. 2 of the circulator CIR3 is connected to Port No. 2 of the micro-resonant cavity WGMR.

[0036] Port No. 3 of the circulator CIR2 is connected to the photodetector PD via the Fabry-Perot resonant cavity filter FPF2, port No. 3 of the circulator CIR3 is connected to the photodetector PD via the Fabry-Perot resonant cavity filter FPF3, and the photodetector PD is connected to the time detection circuit EC.

[0037] The working light source DFB, circulator CIR1, circulator CIR2, circulator CIR3, micro-resonator WGMR, Fabry-Perot resonator filter FPF1, Fabry-Perot resonator filter FPF2, Fabry-Perot resonator filter FPF3, acousto-optic modulator AOM, photodetector PD and time detection circuit EC are all components with polarization-maintaining characteristics, and have the same working wavelength, for example, all are 1550nm.

[0038] The circulator CIR is a three-port optical fiber counterclockwise circulator.

[0039] The working light source DFB is a single longitudinal mode output semiconductor laser, the spectral line width can be several Mhz, the power is greater than 10mW,

[0040] The micro-optical resonant cavity WGMR is a high-Q value whispering gallery type micro-disk resonant cavity, and its material can be fluoride materials such as silicon oxide, calcium fluoride, magnesium fluoride, barium fluoride, etc., and the Q value is greater than 10 9 , with a diameter of several centimeters, a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking, the detection method comprises the following steps:

[0041] Step 1: The single longitudinal mode laser output by the working light source DFB is divided into two paths after passing through the counterclockwise circulator CIR1. One path enters the port 1 of the circulator CIR2, and the other path enters the port 1 of the circulator CIR3 after the frequency is shifted by the acousto-optic modulator AOM so that the system reaches the singular point.

[0042] Step 2: Port 2 of the circulator CIR2 outputs a light wave to port 1 of the micro-resonator WGMR. The light wave is excited inside the micro-resonator WGMR to form Brillouin scattering SBS1 and Rayleigh scattering RBS1 in opposite directions, and passes through port 1 of the micro-resonator WGMR to port 2 of the circulator CIR2; the light waves SBS1 and RBS1 are output from port 3 of the circulator CIR2 and divided into two paths, one of which passes through the Fabry-Perot resonator filter FPF1 to filter out the Brillouin scattering SBS1, and the remaining Rayleigh scattering RBS1 is self-injected back into the working light source DFB through port 3 of the circulator CIR1, and the other path passes through the Fabry-Perot resonator filter FPF2 to filter out the Rayleigh scattering RBS1, and the remaining Brillouin scattering SBS1;

[0043] Step 3: Port 2 of the circulator CIR3 outputs a light wave to port 2 of the micro-resonator WGMR. The light wave is excited inside the micro-resonator WGMR to form Brillouin scattering SBS2 and Rayleigh scattering RBS2 in opposite directions, and passes through port 2 of the micro-resonator WGMR to port 2 of the circulator CIR3; the light waves SBS2 and RBS2 are output from port 3 of the circulator CIR3 and pass through the Fabry-Perot resonator filter FPF3 to filter out the Rayleigh scattering RBS2, leaving the Brillouin scattering SBS2;

[0044] Step 4: The remaining Brillouin scattering SBS1 after passing through the Fabry-Perot resonant cavity filter FPF2 in step 2 and the remaining Brillouin scattering SBS2 after passing through the Fabry-Perot resonant cavity filter FPF3 in step 3 are combined and coupled to generate a beat signal. The frequency period of the beat signal is detected by the time detection circuit EC to calculate the actual rotation speed of the gyroscope.

[0045] Furthermore, the frequency shifting by the acousto-optic modulator AOM makes the system reach a singular point, such as Figure 2 As shown in the figure, due to the sensitivity of the singular point to small disturbances, the frequency of the beat signal begins to grow nonlinearly and the sensitivity increases. The expression of the change of the beat signal frequency and the proportional factor is:

[0046]

[0047]

[0048] Where Δf s is the Brillouin scattering beat frequency signal, γ is the photon attenuation rate, Γ is the Brillouin gain bandwidth, Δf p is the pump light frequency difference, Δf sag is the frequency change caused by the Sagnac effect, Δf c is the critical pump frequency difference of the system at the singular point, S E is the proportional factor, D and n are the cavity diameter and refractive index respectively, and λ is the wavelength of light.

[0049] Furthermore, in step 2, the Rayleigh scattering RBS1 is self-injected back into the working light source DFB through port 3 of the circulator CIR1 to perform self-injection frequency locking as follows:

[0050]

[0051] in, is the difference between the initial frequency of the laser and the resonant frequency of the resonant cavity, is the difference between the steady-state output frequency and the resonant frequency of the resonant cavity, f 0 , f m and f sare the laser initial frequency, the resonant cavity resonant frequency and the steady-state output frequency, respectively. m is the half-width of the resonant cavity, K is the feedback coefficient, α is the coupling coefficient of the resonant cavity, β is the dimensionless coupling ratio between the counter-propagating modes (directly related to the mode splitting), is the phase delay.

[0052] like Figure 3 As shown in the figure, the self-injection locking process is to gradually approach the resonant frequency of the resonant cavity by adjusting the temperature of the working light source or the driving current. At the turning point, it will jump to the region where the internal frequency is stable and be in the self-injection locking state. That is to say, the steady-state frequency of the laser after self-injection locking will be stable near the resonant frequency of the resonant cavity until the free running frequency of the laser exceeds the locking range. When the laser is locked, the resonance curve becomes quasi-rectangular, and the excellent stable output intensity indicates that the frequency of the laser is well locked with the external resonator.

[0053] Furthermore, the Rayleigh scattering RBS1 is injected back into the working light source DFB through port 3 of the circulator CIR1 to narrow the line width. The expression is:

[0054]

[0055] Among them, Δν 0 and Δν p are the laser line width before and after narrowing, Q d and Q m are the Q values ​​of the laser resonant cavity and the gyro resonant cavity, T m is the amplitude of the gyro resonant cavity transfer function, and η is the line width enhancement factor. Figure 4 As shown, the laser linewidth can be effectively reduced by adjusting the resonant cavity Q value and the transfer function amplitude.

[0056] Furthermore, the enhancement of the Sagnac effect near the singular point is limited by the linewidth broadening of the Petermann factor, e.g. Figure 5 As shown in the figure, after the self-injection locking line width is narrowed, the laser noise and beat frequency output signals are,

[0057]

[0058]

[0059] Among them, S v is the laser noise, is the Petermann linewidth enhancement factor, S v0 is the non-enhanced noise far away from the singular point, R v =Δv 0 / Δv pis the line width narrowing ratio, Δf SI is the beat frequency output signal, and Ω is the angular velocity of the gyroscope.

[0060] In summary, the present invention relates to a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking. The DFB is connected to port 1 of CIR1, port 2 of CIR1 is connected to port 1 of CIR2, port 3 of CIR2 is connected to port 3 of CIR1 through FPF1, port 2 of CIR2 is connected to port 1 of WGMR, port 2 of CIR1 is connected to port 1 of CIR3 through AOM, port 2 of CIR3 is connected to port 2 of WGMR, port 3 of CIR2 is connected to PD through FPF2, port 3 of CIR3 is connected to PD through FPF3, and PD is connected to EC. The present invention can effectively suppress laser noise near the singular point and reduce the cost and volume of the gyroscope.

Claims

1. A singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking, Features: The invention comprises a working light source DFB, a circulator CIR1, a circulator CIR2, a circulator CIR3, a micro-resonant cavity WGMR, a Fabry-Perot resonant cavity filter FPF1, a Fabry-Perot resonant cavity filter FPF2, a Fabry-Perot resonant cavity filter FPF3, an acousto-optic modulator AOM, a photodetector PD and a time detection circuit EC; the working light source DFB is connected to port No. 1 of the circulator CIR1, the port No. 2 of the circulator CIR1 is connected to port No. 1 of the circulator CIR2, the port No. 3 of the circulator CIR2 is connected to port No. 3 of the circulator CIR1 through the Fabry-Perot resonant cavity filter FPF1, and the port No. 3 of the circulator CIR1 is connected to the port No. 3 of the circulator CIR2 through the Fabry-Perot resonant cavity filter FPF1. Ports are connected, port No. 2 of the circulator CIR2 is connected to port No. 1 of the micro-resonant cavity WGMR, port No. 2 of the circulator CIR1 is connected to port No. 1 of the circulator CIR3 through an acousto-optic modulator AOM, port No. 2 of the circulator CIR3 is connected to port No. 2 of the micro-resonant cavity WGMR, port No. 3 of the circulator CIR2 is connected to the photodetector PD through a Fabry-Perot resonant cavity filter FPF2, port No. 3 of the circulator CIR3 is connected to the photodetector PD through a Fabry-Perot resonant cavity filter FPF3, and the photodetector PD is connected to a time detection circuit EC.

2. A detection method for singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking, It is characterized in that The following steps are involved: Step 1: The single longitudinal mode laser output by the working light source DFB is divided into two paths after passing through the counterclockwise circulator CIR1. One path enters the port 1 of the circulator CIR2, and the other path enters the port 1 of the circulator CIR3 after the frequency is shifted by the acousto-optic modulator AOM so that the system reaches the singular point. Step 2: Port 2 of the circulator CIR2 outputs a light wave to port 1 of the micro-resonator WGMR. The light wave is excited inside the micro-resonator WGMR to form Brillouin scattering SBS1 and Rayleigh scattering RBS1 in opposite directions, and passes through port 1 of the micro-resonator WGMR to port 2 of the circulator CIR2; the light waves SBS1 and RBS1 are output from port 3 of the circulator CIR2 and divided into two paths, one of which passes through the Fabry-Perot resonator filter FPF1 to filter out the Brillouin scattering SBS1, and the remaining Rayleigh scattering RBS1 is self-injected back into the working light source DFB through port 3 of the circulator CIR1, and the other path passes through the Fabry-Perot resonator filter FPF2 to filter out the Rayleigh scattering RBS1, and the remaining Brillouin scattering SBS1; Step 3: Port 2 of the circulator CIR3 outputs a light wave to port 2 of the micro-resonator WGMR. The light wave is excited inside the micro-resonator WGMR to form Brillouin scattering SBS2 and Rayleigh scattering RBS2 in opposite directions, and passes through port 2 of the micro-resonator WGMR to port 2 of the circulator CIR3; the light waves SBS2 and RBS2 are output from port 3 of the circulator CIR3 and pass through the Fabry-Perot resonator filter FPF3 to filter out the Rayleigh scattering RBS2, leaving the Brillouin scattering SBS2; Step 4: The remaining Brillouin scattering SBS1 after passing through the Fabry-Perot resonant cavity filter FPF2 in step 2 and the remaining Brillouin scattering SBS2 after passing through the Fabry-Perot resonant cavity filter FPF3 in step 3 are combined and coupled to generate a beat signal. The frequency period of the beat signal is detected by the time detection circuit EC to calculate the actual rotation speed of the gyroscope.

3. According to claim 2, a detection method for a singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking, Features: In step 1, the system reaches a singular point by frequency shifting through the acousto-optic modulator AOM, resulting in enhanced sensitivity. The expression of the change of the beat signal frequency and the proportional factor is: Where Δf s is the Brillouin scattering beat frequency signal, γ is the photon attenuation rate, Γ is the Brillouin gain bandwidth, Δf p is the pump light frequency difference, Δf sag is the frequency change caused by the Sagnac effect, Δf c is the critical pump frequency difference of the system at the singular point, S E is the proportional factor, D and n are the cavity diameter and refractive index respectively, and λ is the wavelength of light.

4. The detection method of the singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking according to claim 2, Features: In step 2, the Rayleigh scattering RBS1 is self-injected back into the working light source DFB through port 3 of the circulator CIR1 to perform self-injection frequency locking. The expression is: in, is the difference between the initial frequency of the laser and the resonant frequency of the resonant cavity, is the difference between the steady-state output frequency and the resonant frequency of the resonant cavity, f 0 , f m and f s are the laser initial frequency, the resonant cavity resonant frequency and the steady-state output frequency, respectively. m is the half-width of the resonant cavity, K is the feedback coefficient; β is the dimensionless coupling ratio between the counter-propagating modes, which is directly related to the mode splitting; is the phase delay.

5. The detection method of the singular point enhanced Brillouin micro-optical gyroscope based on self-injection frequency locking according to claim 4, Features: The Rayleigh scattering RBS1 is injected back into the working light source DFB through the port 3 of the circulator CIR1 to narrow the line width. The expression is: Among them, Δν 0 and Δν p are the laser line width before and after narrowing, Q d and Q m are the Q values ​​of the laser resonant cavity and the gyro resonant cavity, T m is the amplitude of the gyro resonant cavity transfer function, η is the linewidth enhancement factor; the enhancement of the Sagnac effect near the singular point will be limited by the linewidth broadening of the Petermann factor, so after introducing the self-injection locking linewidth narrowing, the laser noise and beat frequency output signals are, Among them, S v is the laser noise, is the Petermann linewidth enhancement factor, S v0 is the non-increasing noise far from the singular point, R v =Δv 0 / Δv p is the line width narrowing ratio, Δf SI is the beat frequency output signal, and Ω is the angular velocity of the gyroscope.

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