A fiber optic angular accelerometer capable of suppressing light source noise

Abstract

This invention discloses a fiber optic angular accelerometer capable of suppressing light source noise. In this invention, light emanating from the light source is split into two beams by a beam splitter. The first beam is modulated by a first modulator and input into a first angular motion sensitive channel. A first photodetector detects the intensity of the beam output from the first angular motion sensitive channel and inputs it to a signal processing unit via a first sampling circuit. The second beam is delayed by a delay module by τ0 and then input into a second modulator. The second modulator modulates the input beam and inputs it into a second angular motion sensitive channel. A second photodetector detects the intensity of the beam output from the second angular motion sensitive channel and inputs it to the signal processing unit via a second sampling circuit. The modulation signals of the first and second modulators are provided by first and second signal generators, respectively, with the signal from the second signal generator lagging behind the signal from the first signal generator by τ0. The signal processing unit calculates the angular acceleration based on the received signals.

Description

Technical Field

[0001] This invention relates to a fiber optic angular accelerometer that can suppress light source noise, which can be used in the monitoring and observation of rotational motion, such as vibration monitoring, earthquake early warning, geological and geophysical exploration, gravity gradient observation and other engineering and scientific research fields. Background Technology

[0002] Angular acceleration, as a kinematic parameter, is widely used in applications such as satellite high-attitude jitter control, spacecraft attitude correction, carrier motion control, and seismic wave detection.

[0003] In angular accelerometers, microelectromechanical systems (MEMS) based angular accelerometers are simple to manufacture and inexpensive, offering significant advantages in miniaturization. However, these angular accelerometers have relatively low detection accuracy and are mostly used in applications where high precision is not required. For high-precision measurements, superconducting angular accelerometers have achieved high detection accuracy, but they require bulky, high-power environmental maintenance equipment (such as magnetic shielding devices and cryogenic equipment), and their high cost limits their widespread application.

[0004] Fiber optic angular accelerometers, employing optical fibers as optical waveguides for signal detection, offer the advantage of high precision in optical sensing and have gained increasing attention in recent years. Since optical fibers are typically made of insulating glass, external electromagnetic interference cannot induce current within the fiber through electromagnetic induction, thus fiber optic sensing is unaffected by external electromagnetic interference and possesses inherent environmental adaptability. Fiber optic sensing does not require cryogenic environments and can operate normally at room temperature, high temperature, and low temperature, broadening its measurement applicability. Furthermore, the small size and light weight of optical fibers make them suitable for aerospace applications with strict load or size requirements. However, the largest self-noise in fiber optic angular accelerometers is source noise, primarily manifested as intensity-based noise generated at the source. This noise contributes to the final signal demodulation as an equivalent noise phase contribution, aliasing with the phase of the detected signal and reducing the detection accuracy of the fiber optic angular accelerometer. This invention proposes a novel fiber optic angular accelerometer that significantly suppresses source intensity noise, effectively improving the accuracy of the angular accelerometer. Summary of the Invention

[0005] This invention provides a fiber optic angular accelerometer capable of suppressing light source noise. The system block diagram of this instrument is attached. Figure 1 As shown, the system mainly consists of a light source, beam splitter, delay module, modulator, angular motion sensitive channel, photoelectric detector, signal generator, sampling circuit, and signal processing section. The signal generator provides the modulation signal to the modulator, and the sampling circuit converts the analog signal obtained from the photoelectric detector into the digital signal required for signal processing.

[0006] A fiber optic angular accelerometer capable of suppressing light source noise is characterized by comprising an optical structure, a signal generator, a sampling circuit, and a signal processing unit; the optical structure includes a light source, a beam splitter, a delay module, a modulator, an angular motion sensitive channel, and a photoelectric detector; wherein,

[0007] The light emitted from the light source is split into two beams by the beam splitter.

[0008] The first beam is modulated by the first modulator and then input into the first angular motion sensitive channel. The first photodetector detects the intensity of the beam output from the first angular motion sensitive channel and inputs it to the signal processing unit through the first sampling circuit.

[0009] The second beam is delayed by τ0 by the delay module and then input to the second modulator. The second modulator modulates the input beam and then inputs it to the second angular motion sensitive channel. The second photodetector detects the intensity of the beam output from the second angular motion sensitive channel and inputs it to the signal processing unit through the second sampling circuit.

[0010] The modulation signals of the first modulator and the second modulator are provided by the first signal generator and the second signal generator, respectively, and the signal of the second signal generator lags behind the signal of the first signal generator by τ0.

[0011] The signal processing unit demodulates the signal received by the first photodetector to obtain the Sagnac phase difference. The Sagnac phase difference is obtained by demodulating the signal received by the second photodetector after a delay of -τ0. Then the angular acceleration at time t is calculated as follows: λ is the wavelength of light, c is the speed of light in vacuum, the first angular motion sensitive channel is an annular channel with a diameter of D1, L1 is the length of the first angular motion sensitive channel, the second angular motion sensitive channel is an annular channel with a diameter of D2, and L2 is the length of the second angular motion sensitive channel.

[0012] Furthermore, τ A τ represents the transit time of light in the first angular motion sensitive channel. B This indicates the transit time of light in the second motion-sensitive channel. This represents the equivalent phase contribution of the light source noise at time t. Where Ω(t) represents the angular velocity of the angular motion to be measured.

[0013] Furthermore, the first angular motion sensitive channel is a first fiber optic ring, the second angular motion sensitive channel is a second fiber optic ring, and the first fiber optic ring and the second fiber optic ring have the same structure; or the fast axis and slow axis of a polarization-maintaining fiber are used as the first angular motion sensitive channel and the second angular motion sensitive channel, respectively.

[0014] Furthermore, the optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first optical circulator E, a second optical circulator F, a first Y-type waveguide G serving as the first modulator, a second Y-type waveguide H serving as the second modulator, a first fiber ring I serving as the first angular motion sensitive channel, a second fiber ring J serving as the second angular motion sensitive channel, and a delay fiber ring K serving as the delay module. The light originating from the light source A is split into two paths by the coupler B: the first path passes through the first optical circulator E and the first Y-type waveguide G and is input to the first fiber ring I; the light returning from the first fiber ring I passes through the first Y-type waveguide G and the first optical circulator E and is input to the first photodetector C; the second path passes through the delay fiber ring K, the second optical circulator F, and the second Y-type waveguide H to the second fiber ring J; the light returning from the second fiber ring J passes through the second Y-type waveguide H and the second optical circulator F and is input to the second photodetector D.

[0015] Furthermore, the optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first optical circulator E, a second optical circulator F, a first Y-type waveguide G serving as the first modulator, a second Y-type waveguide H serving as the second modulator, a polarization-maintaining fiber ring N, a delay fiber ring K serving as the delay module; a first polarization beam splitter / combiner L and a second polarization beam splitter / combiner M; the fast axis of the polarization-maintaining fiber ring N serves as the first angular motion sensitive channel, and the slow axis of the polarization-maintaining fiber ring N serves as the second angular motion sensitive channel; light originating from the light source A is split into two paths by the coupler B: the first path passes through the first optical circulator E and inputs into the first Y-type waveguide G, and one output end of the first Y-type waveguide G is connected to the first polarization beam splitter / combiner L. The input end is connected to the first input end of the second polarization beam splitter / combiner M, and the output end of the first polarization beam splitter / combiner L is connected to one end of the polarization-maintaining fiber ring N. The output end of the second polarization beam splitter / combiner M is connected to the other end of the polarization-maintaining fiber ring N. The second path passes through the delay fiber ring K and the second optical circulator F and inputs into the second Y-type waveguide H. One output end of the second Y-type waveguide H is connected to the second input end of the first polarization beam splitter / combiner L, and the other output end is connected to the second input end of the second polarization beam splitter / combiner M. The output beam of the polarization-maintaining fiber ring N returns to the first photodetector C connected to the first optical circulator E and the second photodetector D connected to the second optical circulator F via the second polarization beam splitter / combiner M and the first polarization beam splitter / combiner L, respectively.

[0016] Furthermore, the optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first optical circulator E, a second optical circulator F, a first coupler O, a second coupler P, a first fiber optic ring I serving as a first angular motion sensitive channel, a second fiber optic ring J serving as a second angular motion sensitive channel, and a delay fiber optic ring K serving as the delay module. Light originating from the light source A is split into two paths by the coupler B: the first path passes through the first optical circulator E and the first coupler O to the first fiber optic ring I, then returns to the first coupler O and the first optical circulator E, and finally reaches the first photodetector C; the second path passes through the delay fiber optic ring K, the second optical circulator F, and the second coupler P to the second fiber optic ring J, then returns to the second coupler P and the second optical circulator F, and finally reaches the second photodetector D; a first modulator Q is connected in series in the first fiber optic ring I, and a second modulator R is connected in series in the second fiber optic ring J.

[0017] Furthermore, the optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first coupler O, a second coupler P, a first fiber ring I serving as a first angular motion sensitive channel, a second fiber ring J serving as a second angular motion sensitive channel, and a delay fiber ring K serving as the delay module. Light originating from the light source A is split into two paths by the coupler B: the first path goes through the first coupler O to the first fiber ring I, and then returns through the first coupler O to the first photodetector C; the second path goes through the delay fiber ring K and the second coupler P to the second fiber ring J, and then returns through the second coupler P to the second photodetector D; a first modulator Q is connected in series in the first fiber ring I, and a second modulator R is connected in series in the second fiber ring J.

[0018] Furthermore, the optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first coupler O, a second coupler P, a first fiber ring I serving as the first angular motion sensitive channel, a second fiber ring J serving as the second angular motion sensitive channel, a delay fiber ring K serving as the delay module, a first depolarizer S, a second depolarizer T, a third depolarizer U, a fourth depolarizer V, and a light source depolarizer W. Light originating from the light source A is split into two paths at the coupler B after passing through the light source depolarizer W: the first path passes through the first coupler O to the first fiber ring I, and then returns via the first coupler O to the first photodetector C; the second path passes through the delay fiber ring K and the second coupler P to the second fiber ring J, and then returns via the second coupler P to the second photodetector C; the first fiber ring I is connected in series with a first modulator Q, a first depolarizer S, and a second depolarizer T, and the second fiber ring J is connected in series with a second modulator R, a third depolarizer U, and a fourth depolarizer V.

[0019] Without loss of generality, with appendix Figure 2The structure is analyzed as shown. The beam splitter is implemented using a coupler, the delay module uses a delay fiber ring, the modulator uses a Y-shaped waveguide, and the angular motion sensitive channel is a fiber ring. Light originating from the light source is split into two paths by the coupler: the first path passes through the first optical circulator, the first Y-shaped waveguide to the first fiber ring, then returns to the first Y-shaped waveguide, the first optical circulator, and finally reaches the first photodetector; the second path passes through the delay fiber ring, the second optical circulator, the second Y-shaped waveguide to the second fiber ring, then returns to the second Y-shaped waveguide, the second optical circulator, and finally reaches the second photodetector.

[0020] The light source contains intensity noise, which is usually represented by the additive noise model of the following formula:

[0021] I(t) = I0 + I N (t)

[0022] Where I(t) represents the light intensity output by the light source, I0 represents the DC component of the light source output, and I N (t) represents intensity noise.

[0023] The signal received from the first photodetector can be represented as:

[0024]

[0025] in This represents the Sagnac phase difference accumulated by the light in the first fiber loop. The phase modulation signal τ is applied to the first Y-type waveguide. A This represents the transit time of light in the first fiber loop. According to the Sagnac effect, the relationship between the Sagnac phase difference and the angular velocity Ω of the measured angular motion is:

[0026]

[0027] Where λ is the wavelength of light, L1 is the length of the first fiber optic loop, D1 is the diameter of the first fiber optic loop, and c is the speed of light in vacuum. For convenience, let λ be the wavelength of light. This is the scaling factor for the first fiber ring.

[0028] The signal received from the second photodetector can be represented as:

[0029]

[0030] in This represents the Sagnac phase difference accumulated by the light in the second fiber loop. The phase modulation signal loaded onto the second Y-type waveguide is the same as the phase modulation signal loaded onto the first Y-type waveguide, τ. BLet τ0 represent the transit time of light in the first fiber loop, and let τ0 represent the transit time of light in the delay fiber loop (equal to the delay τ0 generated by the delay module). According to the Sagnac effect, Where L2 is the length of the second fiber optic loop and D2 is the diameter of the second fiber optic loop. For convenience, let's call them... This is the scaling factor for the second fiber optic ring.

[0031] By analyzing I A (t), I B (t) Demodulation (which can be achieved using the phase-generated carrier method) yields the Sagnac phase difference between the signals received at the first and second photodetectors:

[0032]

[0033]

[0034] in, The equivalent phase contribution of the light source noise is represented by I. N (t) Aligned in time sequence.

[0035] At this point, the angular acceleration can be obtained through the following calculation:

[0036]

[0037] Note that, in addition to the angular acceleration represented by the first term on the right, it also includes the light source noise term represented by the second term, which is superimposed on the actual angular acceleration and reduces the detection accuracy of the fiber optic angular accelerometer.

[0038] This invention uses the following method to obtain angular acceleration that suppresses the influence of light source noise:

[0039] The first and second fiber optic rings should use the same parameters (or directly adopt the parameters provided). Figure 2 The polarization multiplexing structure shown replaces two fiber rings with a single fiber ring through polarization multiplexing, where the fast and slow axes of the polarization-maintaining fiber are used as the first and second motion-sensitive channels, respectively, thus K A =K B , τ A =τ B A modulation delay of τ0 is introduced between the first Y-type waveguide and the second Y-type waveguide. This modulation delay can be achieved by one of the following methods: inserting a delay unit between the second signal generator and the second modulator, delaying the output signal of the second signal generator by τ0; or inserting a delay unit between the first signal generator and the first modulator, delaying the output signal of the first signal generator by -τ0. At this time, the signals received at the first photodetector and the second photodetector are respectively:

[0040]

[0041]

[0042] The signal received at the second photodetector is delayed by -τ0 (this can be achieved by adding a delay circuit to the second sampling circuit to delay it by -τ0; or by adding a delay circuit to the first sampling circuit to delay it by τ0; or by using a digital delay for the signal from the second sampling circuit in the signal processing section):

[0043]

[0044] At this point, the timing of the light source noise is aligned. For I A (t), I B (t+τ0) Demodulation (using the phase-generated carrier method) yields the Sagnac phase difference between the signals received at the first and second photodetectors, which are respectively:

[0045]

[0046]

[0047] Angular acceleration can be obtained through the following calculation:

[0048]

[0049] It can be seen that the light source noise term in the angular acceleration obtained at this time is eliminated and is not affected by the equivalent phase aliasing of the light source noise.

[0050] Compared with the prior art, the positive effects of the present invention are as follows:

[0051] This invention detects rotational motion based on the Sagnac effect. The Sagnac phase difference is only proportional to the equivalent area of ​​the closed optical path perpendicular to the rotation axis, and is independent of the shape of the closed optical path and the position of the rotation axis. This lowers the barrier to entry for using it as a rotational motion sensor, which is beneficial for improving sensor stability and reducing sensitivity to sensor installation from a fundamental perspective. Compared with existing fiber optic angular accelerometer structures, this invention can suppress light source noise, achieving a higher signal-to-noise ratio and thus improving angular acceleration detection accuracy. Compared with schemes that use algorithms to suppress light source noise, this invention's solution is completed at the system level, without losing information entropy in algorithm processing. Furthermore, if further accuracy improvement is needed, other algorithms for suppressing light source noise can be superimposed, providing better scalability. This invention introduces a delay module into the optical path, introducing a delay difference between the two angular motion sensitive channels required for angular acceleration measurement. Simultaneously, by further introducing a modulation delay, the timing alignment of light source noise in the two angular motion sensitive channels is achieved, thereby eliminating light source noise. Attached Figure Description

[0052] Figure 1 This is a block diagram of an angular accelerometer signal system that can suppress light source noise.

[0053] Figure 2 The optical structure for a high-precision polarization-maintaining Sagnac fiber optic angular accelerometer.

[0054] Figure 3 This is the optical structure for a high-precision polarization-maintaining Sagnac structure fiber optic angular accelerometer.

[0055] Figure 4 This is the optical structure for a medium-to-high precision Sagnac fiber optic angular accelerometer.

[0056] Figure 5 The optical structure for a low-to-medium cost polarization-maintaining Sagnac fiber optic angular accelerometer.

[0057] Figure 6 This is the optical structure for a low-cost, polarization-depolarized single-mode fiber angular accelerometer. Detailed Implementation

[0058] The present invention will now be described in further detail with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0059] Option 1: As attached Figure 2 As shown in the diagram. Light source A can be an SLD or ASE light source. A Y-shaped waveguide polarizes, splits, and modulates the light. The light originating from light source A is split into two paths by coupler B: the first path passes through the first optical circulator E, the first Y-shaped waveguide G to the first fiber ring I, then returns to the first Y-shaped waveguide G, the first optical circulator E, and finally reaches the first photodetector C; the second path passes through the time-delay fiber ring K, the second optical circulator F, the second Y-shaped waveguide H to the second fiber ring J, then returns to the second Y-shaped waveguide H, the second optical circulator F, and finally reaches the second photodetector D.

[0060] Option 2: As attached Figure 3As shown in the diagram. Light source A can be an SLD or ASE light source. Light originating from light source A is split into two paths by coupler B: the first path passes through the first optical circulator E, the first Y-type waveguide G, the first polarization beam splitter / combiner L, and the second polarization beam splitter / combiner M to the polarization-maintaining fiber ring N, then returns to the first Y-type waveguide G and the first optical circulator E via the second polarization beam splitter / combiner M and the first polarization beam splitter / combiner L, finally reaching the first photodetector C; the second path passes through the time-delay fiber ring K, the second optical circulator F, and the second Y-type waveguide H, passing through the first polarization beam splitter / combiner L and the second polarization beam splitter / combiner M to the fiber ring N, then returns to the second Y-type waveguide H and the second optical circulator F via the second polarization beam splitter / combiner M and the first polarization beam splitter / combiner L, finally reaching the second photodetector D.

[0061] Option 3: As attached Figure 4 As shown in the diagram. Light source A can be an SLD or ASE light source, and the modulator can be an electro-optic modulator such as a piezoelectric ceramic. Light originating from light source A is split into two paths by coupler B: the first path passes through the first optical circulator E, the first coupler O to the first fiber optic ring I, then returns to the first coupler O, the first optical circulator E, and finally reaches the first photodetector C; the second path passes through the delay fiber optic ring K, the second optical circulator F, the second coupler P to the second fiber optic ring J, then returns to the second coupler P, the second optical circulator F, and finally reaches the second photodetector D; the first modulator Q is connected in series in the first fiber optic ring I, and the second modulator R is connected in series in the second fiber optic ring J.

[0062] Option 4: As attached Figure 5 As shown in the diagram. Light source A can be an SLD or ASE light source, and the modulator can be an electro-optic modulator such as a piezoelectric ceramic. Light originating from light source A is split into two paths by coupler B: the first path passes through the first coupler O to the first fiber ring I, then returns to the first coupler O, and finally reaches the first photodetector C; the second path passes through the delay fiber ring K and the second coupler P to the second fiber ring J, then returns to the second coupler P, and finally reaches the second photodetector D; the first modulator Q is connected in series in the first fiber ring I, and the second modulator R is connected in series in the second fiber ring J.

[0063] Option 5: As attached Figure 6As shown in the diagram. Light source A can be an SLD or ASE light source, and the modulator can be an electro-optic modulator such as a piezoelectric ceramic modulator. Light from light source A passes through the depolarizer W and is split into two paths at coupler B: the first path passes through the first coupler O to the first fiber ring I, then returns to the first coupler O, and finally reaches the first photodetector C; the second path passes through the delay fiber ring K and the second coupler P to the second fiber ring J, then returns to the second coupler P, and finally reaches the second photodetector C. The first fiber ring I is connected in series with the first modulator Q, the first depolarizer S, and the second depolarizer T; the second fiber ring J is connected in series with the second modulator R, the third depolarizer U, and the fourth depolarizer V. If high accuracy is not required, one or more depolarizers can be removed from the first to fourth depolarizers.

[0064] Although specific embodiments of the invention have been disclosed for illustrative purposes to aid in understanding and implementing the invention, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the content disclosed in the preferred embodiments, and the scope of protection claimed by the invention is defined by the claims.

Claims

1. A fiber optic angular accelerometer capable of suppressing light source noise, characterized in that, It includes an optical structure, a signal generator, a sampling circuit, and a signal processing unit; the optical structure includes a light source, a beam splitter, a delay module, a modulator, an angular motion sensitive channel, and a photoelectric detector; wherein, The light emitted from the light source is split into two beams by the beam splitter. The first beam is modulated by the first modulator and then input into the first angular motion sensitive channel. The first photodetector detects the intensity of the beam output from the first angular motion sensitive channel and inputs it to the signal processing unit through the first sampling circuit. The second beam is delayed by τ0 by the delay module and then input to the second modulator. The second modulator modulates the input beam and then inputs it to the second angular motion sensitive channel. The second photodetector detects the intensity of the beam output from the second angular motion sensitive channel and inputs it to the signal processing unit through the second sampling circuit. The modulation signals of the first modulator and the second modulator are provided by the first signal generator and the second signal generator, respectively, and the signal of the second signal generator lags behind the signal of the first signal generator by τ0. The signal processing unit demodulates the signal received by the first photodetector to obtain the Sagnac phase difference. The Sagnac phase difference is obtained by demodulating the signal received by the second photodetector after a delay of -τ0. Then the angular acceleration at time t is calculated as follows: λ is the wavelength of light, c is the speed of light in vacuum, the first angular motion sensitive channel is an annular channel with a diameter of D1, L1 is the length of the first angular motion sensitive channel, the second angular motion sensitive channel is an annular channel with a diameter of D2, and L2 is the length of the second angular motion sensitive channel.

2. The fiber optic angular accelerometer according to claim 1, characterized in that, τ A τ represents the transit time of light in the first angular motion sensitive channel. B This indicates the transit time of light in the second motion-sensitive channel. This represents the equivalent phase contribution of the light source noise at time t. Where Ω(t) represents the angular velocity of the angular motion to be measured.

3. The fiber optic angular accelerometer according to claim 1, characterized in that, The first angular motion sensitive channel is a first fiber optic ring, and the second angular motion sensitive channel is a second fiber optic ring, with the first and second fiber optic rings having the same structure; or the fast and slow axes of a polarization-maintaining fiber are used as the first and second angular motion sensitive channels, respectively.

4. The fiber optic angular accelerometer according to claim 1, 2, or 3, characterized in that, The optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first optical circulator E, a second optical circulator F, a first Y-type waveguide G serving as the first modulator, a second Y-type waveguide H serving as the second modulator, a first fiber ring I serving as the first angular motion sensitive channel, a second fiber ring J serving as the second angular motion sensitive channel, and a delay fiber ring K serving as the delay module. The light originating from light source A is split into two paths by coupler B: the first path passes through the first optical circulator E and the first Y-type waveguide G and is input into the first fiber optic ring I; the light returning from the first fiber optic ring I passes through the first Y-type waveguide G and the first optical circulator E and is input into the first photodetector C; the second path passes through the time-delay fiber optic ring K, the second optical circulator F, and the second Y-type waveguide H to the second fiber optic ring J; the light returning from the second fiber optic ring J passes through the second Y-type waveguide H and the second optical circulator F and is input into the second photodetector D.

5. The fiber optic angular accelerometer according to claim 1, 2, or 3, characterized in that, The optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first optical circulator E, a second optical circulator F, a first Y-type waveguide G serving as the first modulator, a second Y-type waveguide H serving as the second modulator, a polarization-maintaining fiber ring N, a delay fiber ring K serving as the delay module, a first polarization beam splitter / combiner L, and a second polarization beam splitter / combiner M; the fast axis of the polarization-maintaining fiber ring N serves as the first angular motion sensitive channel, and the slow axis of the polarization-maintaining fiber ring N serves as the second angular motion sensitive channel. The light originating from light source A is split into two paths by coupler B: the first path passes through the first optical circulator E and enters the first Y-type waveguide G. One output end of the first Y-type waveguide G is connected to the first input end of the first polarization beam splitter / combiner L, and the other output end is connected to the first input end of the second polarization beam splitter / combiner M. The output end of the first polarization beam splitter / combiner L is connected to one end of the polarization-maintaining fiber ring N, and the output end of the second polarization beam splitter / combiner M is connected to the other end of the polarization-maintaining fiber ring N. The second path passes through the time-delay fiber ring K and the second optical circulator F, and is input into the second Y-type waveguide H. One output end of the second Y-type waveguide H is connected to the second input end of the first polarization beam splitter / combiner L, and the other output end is connected to the second input end of the second polarization beam splitter / combiner M. The output beam of the polarization-maintaining fiber ring N returns to the first photodetector C connected to the first optical circulator E and the second photodetector D connected to the second optical circulator F via the second polarization beam splitter / combiner M and the first polarization beam splitter / combiner L, respectively.

6. The fiber optic angular accelerometer according to claim 1, 2, or 3, characterized in that, The optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first optical circulator E, a second optical circulator F, a first coupler O, a second coupler P, a first fiber optic loop I serving as a first angular motion sensitive channel, a second fiber optic loop J serving as a second angular motion sensitive channel, and a delay fiber optic loop K serving as the delay module. The light originating from light source A is split into two paths by coupler B: the first path passes through the first optical circulator E and the first coupler O to the first fiber optic ring I, then returns to the first coupler O and the first optical circulator E, and finally reaches the first photodetector C; the second path passes through the delay fiber optic ring K, the second optical circulator F, and the second coupler P to the second fiber optic ring J, then returns to the second coupler P and the second optical circulator F, and finally reaches the second photodetector D; the first modulator Q is connected in series in the first fiber optic ring I, and the second modulator R is connected in series in the second fiber optic ring J.

7. The fiber optic angular accelerometer according to claim 1, 2, or 3, characterized in that, The optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first coupler O, a second coupler P, a first fiber optic loop I serving as a first angular motion sensitive channel, a second fiber optic loop J serving as a second angular motion sensitive channel, and a delay fiber optic loop K serving as the delay module. The light originating from light source A is split into two paths by coupler B: the first path goes through the first coupler O to the first fiber ring I, and then returns through the first coupler O to the first photodetector C; the second path goes through the delay fiber ring K and the second coupler P to the second fiber ring J, and then returns through the second coupler P to the second photodetector D; the first modulator Q is connected in series in the first fiber ring I, and the second modulator R is connected in series in the second fiber ring J.

8. The fiber optic angular accelerometer according to claim 1, 2, or 3, characterized in that, The optical structure includes a light source A, a coupler B serving as the beam splitter, a first photodetector C, a second photodetector D, a first coupler O, a second coupler P, a first fiber optic ring I serving as the first angular motion sensitive channel, a second fiber optic ring J serving as the second angular motion sensitive channel, a delay fiber optic ring K serving as the delay module, a first depolarizer S, a second depolarizer T, a third depolarizer U, a fourth depolarizer V, and a light source depolarizer W. The light originating from light source A is split into two paths at coupler B after passing through the depolarizer W: the first path passes through the first coupler O to the first fiber ring I, and then returns through the first coupler O to the first photodetector C; the second path passes through the delay fiber ring K and the second coupler P to the second fiber ring J, and then returns through the second coupler P to the second photodetector C; the first fiber ring I is connected in series with the first modulator Q, the first depolarizer S and the second depolarizer T, and the second fiber ring J is connected in series with the second modulator R, the third depolarizer U and the fourth depolarizer V.

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