A resonant micro-optical gyroscope based on a variable optical fiber beam splitter and a closed-loop control method thereof

Abstract

This invention proposes a resonant micro-optical gyroscope based on a variable fiber beam splitter and its closed-loop control method, belonging to the field of resonant optical gyroscope technology. It includes a laser, a variable fiber beam splitter, phase modulators PMⅠ and PMⅡ, circulator Ⅰ and circulator Ⅱ, a 95% 2×2 coupler, photodetectors PDⅠ and PDⅡ, a whispering-gallery resonator, a digital-to-analog interface, a digital system, and an analog-to-digital interface. This invention achieves a dual-closed-loop structure by designing a Schmitt-type closed-loop switching, a linear region judgment scheme, and an automatic reset operation, thereby improving the linearity and dynamic range of the ROG output.

Description

Technical Field

[0001] This invention belongs to the field of resonant optical gyroscope technology, specifically, it relates to a resonant micro-optical gyroscope based on a variable fiber optic beam splitter and its closed-loop control method. Background Technology

[0002] A resonant optical gyroscope (ROG) is a sensor that measures the angular velocity of a carrier in inertial space using the Sagnac effect. It is widely used in aviation, aerospace, marine, and medical fields. ROGs can achieve high detection accuracy while reducing size and cost, and also reduce non-reciprocity errors caused by the environment. Driven by the rapid development of microsatellites and micro-UAVs, miniaturized, high-precision ROGs based on microcavities have become a research focus. Whispering Gallery Mode (WGM) resonant cavities are based on the principle of total internal reflection of light, confining the incident light within the cavity, achieving up to 10... 9 The WGM resonant cavity boasts an order of magnitude high quality factor (Q), with a larger Q value resulting in higher gyroscope resolution. Furthermore, due to its extremely narrow spectral linewidth and tiny mode volume, it is highly sensitive to external disturbances, making it a promising candidate for realizing highly sensitive, high-precision miniature ROGs.

[0003] However, currently reported ROGs have not yet reached theoretical accuracy due to noise effects such as the Kerr effect, Shupe effect, polarization noise, and backscattering noise. While the Kerr and photothermal effects can be effectively suppressed by carefully controlling the incident light power, backscattering noise caused by cavity surface defects is typically addressed by using broadband light sources to reduce coherence length or by using narrow-linewidth light sources with modulation and demodulation techniques for carrier suppression or large-frequency-difference filtering. However, residual backscattering noise still remains mixed in the measured signal, and the impact of system delay and phase fluctuations on gyroscope sensitivity during demodulation is often ignored. Another time-division multiplexing suppression scheme using an optical switch to separate the signal light and backscattered light can theoretically improve detection accuracy, but it can only form a single closed-loop structure, resulting in poor scaling factor linearity and a small dynamic range for the ROG. A variable fiber beam splitter, through voltage regulation, can act as both an optical switch and a 50:50 beam splitter to form a dual closed-loop structure, potentially improving detection accuracy while achieving a smaller ROG. Summary of the Invention

[0004] To address the drawbacks of traditional ROGs, such as large size and low precision, this invention proposes a resonant micro-optical gyroscope based on a variable fiber beam splitter and its closed-loop control method. By designing a Schmitt-type closed-loop switching, a linear region judgment scheme, and an automatic reset operation, a dual closed-loop structure is achieved, thereby improving the linearity and dynamic range of the ROG output.

[0005] This invention is achieved through the following technical solution:

[0006] A resonant micro-optical gyroscope based on a variable fiber beam splitter:

[0007] The resonant micro-optical gyroscope includes a laser, a variable fiber beam splitter, a phase modulator PMⅠ, a phase modulator PMⅡ, a circulator Ⅰ, a circulator Ⅱ, a 95% 2×2 coupler, a photodetector PDⅠ, a photodetector PDⅡ, a whispering-gallery resonator, a digital-to-analog interface, a digital system, and an analog-to-digital interface.

[0008] The laser is connected to a variable fiber beam splitter and a digital-to-analog interface, respectively. The variable fiber beam splitter is connected to a phase modulator PMⅠ and a phase modulator PMⅡ, respectively. The phase modulator PMⅠ is connected to a circulator Ⅰ and a digital-to-analog interface, respectively. The phase modulator PMⅡ is connected to a circulator Ⅱ and a digital-to-analog interface, respectively.

[0009] The circulator I is connected to a 95% 2×2 coupler and a photodetector PD I, respectively. The circulator II is connected to a 95% 2×2 coupler and a photodetector PD II, respectively. Both the photodetector PD I and the photodetector PD II are connected to an analog-to-digital interface.

[0010] The 95% 2×2 coupler is connected to the whispering-gallery resonator.

[0011] The digital-to-analog interface and the analog-to-digital interface are connected through a digital system.

[0012] Furthermore, the digital-to-analog interface includes a digital-to-analog converter (ADC) I, a digital-to-analog converter (ADC) II, a digital-to-analog converter (ADC) III, and a digital-to-analog converter (ADC) IV;

[0013] The digital-to-analog converter ADCⅠ is connected to the variable fiber beam splitter;

[0014] The digital-to-analog converter ADCⅡ is connected to the phase modulator PMⅡ.

[0015] The digital-to-analog converter ADCⅢ is connected to the phase modulator PMⅠ.

[0016] The digital-to-analog converter (ADCⅣ) is connected to the laser.

[0017] Furthermore, the digital system includes an orthogonal demodulation module I, an orthogonal demodulation module II, a time-division multiplexing and closed-loop switching module, a modulation signal generation module, and a laser frequency locking control module;

[0018] The modulation signal generation module is connected to both the digital-to-analog converter ADCⅡ and the digital-to-analog converter ADCⅢ.

[0019] The demodulated signals output by the quadrature demodulation module I and the quadrature demodulation module II are subtracted to obtain two signals, which are used to achieve laser frequency locking and serve as the output of the gyroscope system.

[0020] The laser frequency locking control module is connected to the subtraction signal of quadrature demodulation module I and quadrature demodulation module II.

[0021] Furthermore, the analog-to-digital interface includes a low-pass filter I, a low-pass filter II, an analog-to-digital converter ADC I, and an analog-to-digital converter ADC II;

[0022] The low-pass filter I is connected to the photodetector PDII and the analog-to-digital converter ADCI, respectively; the low-pass filter II is connected to the photodetector PDI and the analog-to-digital converter ADCII, respectively.

[0023] The analog-to-digital converter ADCⅠ is connected to the quadrature demodulation module Ⅰ; the analog-to-digital converter ADCⅡ is connected to the quadrature demodulation module Ⅱ.

[0024] A closed-loop control method for a resonant micro-optical gyroscope based on a variable fiber beam splitter:

[0025] The closed-loop control method is specifically as follows:

[0026] The laser beam is split by a variable fiber beam splitter, and the split beams are respectively input to phase modulator PMⅠ and phase modulator PMⅡ for phase modulation.

[0027] The beam modulated by phase modulator PMⅠ enters circulator Ⅰ, and the beam modulated by phase modulator PMⅡ enters circulator Ⅱ. The beams output from circulator Ⅰ and circulator Ⅱ are combined by a 95% 2×2 coupler and input to the whispering gallery resonator.

[0028] The beam is reflected multiple times within the whispering-gallery resonator. The beam reflected from the whispering-gallery resonator then passes through the 95% 2×2 coupler again and enters circulator I and circulator II respectively.

[0029] The light beam entering circulator I is converted into a voltage signal by photodetector PD I, and after high-frequency noise is filtered out by low-pass filter I, it is converted into a digital signal by analog-to-digital converter ADC I and sent to quadrature demodulation module I;

[0030] The light beam entering circulator II is converted into a voltage signal by photodetector PDII, and after high-frequency noise is filtered out by low-pass filter II, it is converted into a digital signal by analog-to-digital converter ADCII and sent to quadrature demodulation module II;

[0031] The demodulated signals output from the quadrature demodulation module I and the quadrature demodulation module II are subtracted to obtain two signals. One signal is input to the laser frequency locking control module, and the other signal is used as the output of the gyroscope system.

[0032] Furthermore, one signal input to the laser frequency locking control module is converted into a digital electrical signal by the digital-to-analog converter (ADC). The laser receives the digital electrical signal to adjust the output frequency.

[0033] Simultaneously, the signal generated by the laser frequency locking control module is sent to the modulation signal generation module, which generates two sinusoidal electrical signals. These signals are then sent to the phase modulator PMII and phase modulator PMⅠ via the digital-to-analog converter ADCⅡ and digital-to-analog converter ADCⅢ, respectively. The phase modulators PMⅡ and PMⅠ adjust their phases according to the received signals.

[0034] Furthermore, the time-division multiplexing and closed-loop switching module controls the variable fiber beam splitter through the digital-to-analog converter ADCⅠ, and realizes single-to-dual closed-loop switching based on the demodulated output voltage corresponding to the system's sensitive angular velocity through a Schmitt trigger judgment scheme and automatic reset operation.

[0035] Furthermore, the Schmitt trigger detection scheme specifically involves setting a low threshold voltage V. set l High threshold voltage V set_h and the counter time Cnt_time;

[0036] When the demodulated output voltage exceeds the high threshold voltage V set_h When the timing reaches Cnt_time, the Flag signal is set to -1. The time division multiplexing and closed-loop switching module uses analog-to-digital converter ADCⅠ to put the variable fiber beam splitter into a 50:50 optical coupler state. The modulation signal generation module uses analog-to-digital converter ADCⅡ to superimpose a sawtooth wave frequency shift signal on the original sine wave modulation signal, and completes the second closed loop on the phase modulator PMⅡ, so that the system switches from a single closed-loop state to a dual closed-loop state.

[0037] When the demodulated output voltage is less than the low threshold voltage V set_l When the timing reaches Cnt_time, the Flag signal is set to +1. The time division multiplexing and closed-loop switching module uses the analog-to-digital converter ADCⅠ to put the variable fiber beam splitter into an optical switch state. The modulation signal generation module only uses the analog-to-digital converter ADCⅡ to perform sine wave modulation on the phase modulator PMⅡ. The system switches from a dual closed-loop state to a single closed-loop state.

[0038] In single-loop mode, the backscattered light corresponding to the two optical paths is collected by analog-to-digital converters ADCⅠ and ADCⅡ respectively, and the collected values ​​are updated in real time using the moving average. When the system switches to dual-loop mode, the corresponding average is used as an error compensation factor to optimize the quadrature demodulation output in dual-loop mode.

[0039] An electronic device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the above method.

[0040] A computer-readable storage medium for storing computer instructions that, when executed by a processor, implement the steps of the above-described method.

[0041] Beneficial effects of the invention

[0042] This invention employs a high-Q WGM resonant cavity as the core sensitive device to reduce size and improve sensitivity. It uses a variable fiber beam splitter for time-division multiplexing to separate backscattered light and an orthogonal lock-in amplifier to suppress residual backscattered noise, effectively improving the accuracy, sensitivity, and robustness of the ROG. It also designs a Schmitt-type closed-loop switching, linear region judgment scheme, and automatic reset operation to achieve a dual closed-loop structure, thereby improving the linearity and dynamic range of the ROG output.

[0043] By using a variable fiber beam splitter and phase modulator, the system can more precisely control the phase and intensity of the beam, thereby improving measurement accuracy and sensitivity; the laser frequency locking control module and closed-loop control enable the laser frequency to be dynamically locked to the resonant frequency of the resonant cavity, improving the stability and reliability of the system. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the resonant micro-light gyroscope system of the present invention.

[0045] Figure 2 This is a schematic diagram of the Schmidt-type closed-loop switching and linear region determination of the present invention.

[0046] Figure 3 This is a schematic diagram of the automatic reset operation of the present invention, wherein... Figure 3 -(a) is a diagram of the reset frequency sweep scheme. Figure 3 -(b) is a diagram of the linear region judgment scheme.

[0047] The components include: laser—1, variable fiber beam splitter—2, phase modulator PMⅠ—3, phase modulator PMⅡ—4, circulator Ⅰ—5, circulator Ⅱ—6, 95% 2×2 coupler—7, photodetector PDⅠ—8, photodetector PDⅡ—9, whispering gallery resonator—10, low-pass filter Ⅰ—11, low-pass filter Ⅱ—12, analog-to-digital converter ADCⅠ—13, analog-to-digital converter ADCⅡ—14, digital-to-analog converter ADCⅠ—15, digital-to-analog converter ADCⅡ—16, digital-to-analog converter ADCⅢ—17, digital-to-analog converter ADCⅣ—18, quadrature demodulation module Ⅰ—19, and quadrature demodulation module Ⅱ—20. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0050] This invention proposes a resonant micro-optical gyroscope based on a variable fiber optic beam splitter and its closed-loop control method, belonging to the field of resonant optical gyroscope technology.

[0051] A resonant micro-optical gyroscope based on a variable fiber beam splitter, the resonant micro-optical gyroscope comprising a laser 1, a variable fiber beam splitter 2, a phase modulator PMⅠ 3, a phase modulator PMⅡ 4, a circulator Ⅰ 5, a circulator Ⅱ 6, a 95% 2×2 coupler 7, a photodetector PDⅠ 8, a photodetector PDⅡ 9, a whispering-gallery resonator 10, a digital-to-analog interface, a digital system, and an analog-to-digital interface;

[0052] The laser 1 is connected to the variable fiber beam splitter 2 and the digital-to-analog interface respectively. The variable fiber beam splitter 2 is connected to the phase modulator PMⅠ3 and the phase modulator PMⅡ4 respectively. The phase modulator PMⅠ3 is connected to the circulator Ⅰ5 and the digital-to-analog interface respectively. The phase modulator PMⅡ4 is connected to the circulator Ⅱ6 and the digital-to-analog interface respectively.

[0053] The circulator I5 is connected to the 95% 2×2 coupler 7 and the photodetector PD I8 respectively, and the circulator II6 is connected to the 95% 2×2 coupler 7 and the photodetector PD II9 respectively. The photodetectors PD I8 and PD II9 are both connected to the analog-to-digital interface.

[0054] The 95% 2×2 coupler 7 is connected to the whispering wall resonator 10;

[0055] The digital-to-analog interface and the analog-to-digital interface are connected through a digital system.

[0056] The digital-to-analog interface includes digital-to-analog converter ADCⅠ15, digital-to-analog converter ADCⅡ16, digital-to-analog converter ADCⅢ17, and digital-to-analog converter ADCⅣ18;

[0057] The digital-to-analog converter ADCⅠ15 is connected to the variable fiber beam splitter 2;

[0058] The digital-to-analog converter ADCⅡ16 is connected to the phase modulator PMⅡ4.

[0059] The digital-to-analog converter ADCⅢ17 is connected to the phase modulator PMⅠ3.

[0060] The digital-to-analog converter ADCⅣ18 is connected to the laser 1.

[0061] The digital system includes an orthogonal demodulation module I 19, an orthogonal demodulation module II 20, a time-division multiplexing and closed-loop switching module 21, a modulation signal generation module 22, and a laser frequency locking control module 23;

[0062] The modulation signal generation module 22 is connected to the digital-to-analog converter ADCⅡ16 and the digital-to-analog converter ADCⅢ17 respectively.

[0063] The demodulated signals output by the quadrature demodulation module I19 and the quadrature demodulation module II20 are subtracted to obtain two signals, which are used to realize laser frequency locking and serve as the output of the gyroscope system.

[0064] The laser frequency locking control module 23 is connected to the subtraction signal of the quadrature demodulation module I 19 and the quadrature demodulation module II 20.

[0065] The analog-to-digital interface includes a low-pass filter I 11, a low-pass filter II 12, an analog-to-digital converter ADC I 13, and an analog-to-digital converter ADC II 14;

[0066] The low-pass filter I11 is connected to the photodetector PDⅡ9 and the analog-to-digital converter ADCⅠ13, respectively; the low-pass filter II12 is connected to the photodetector PDⅠ8 and the analog-to-digital converter ADCⅡ14, respectively.

[0067] The analog-to-digital converter ADCⅠ13 is connected to the quadrature demodulation moduleⅠ19; the analog-to-digital converter ADCⅡ14 is connected to the quadrature demodulation moduleⅡ20.

[0068] The transmission of photoelectric signals in the resonant micro-optical gyroscope is specifically as follows: a tunable laser is connected to a variable fiber beam splitter; the two outputs of the variable fiber beam splitter are connected to a first phase modulator and a second phase modulator, respectively; the first phase modulator is connected to a circulator, and similarly, the second phase modulator is connected to a circulator; the second output terminal of the first and second circulators is connected to a 95% coupler and enters the WGM resonant cavity; the third output terminal of the first and second circulators is connected to photodetectors PDⅠ and PDⅡ; the output signals of photodetectors PDⅠ and PDⅡ are connected to low-pass filters Ⅰ and Ⅱ, respectively, and thus enter the digital system.

[0069] The linearly polarized light emitted by the fiber laser 1 is split into one beam or two beams of equal power after passing through the variable fiber beam splitter 2. The optical signal is modulated into a sinusoidal signal after passing through the lithium niobate phase modulators 3 and 4, and then enters the WGM resonant cavity 10 through the circulators 5 and 6 and the 95% 2x2 fiber coupler 7.

[0070] In the digital system, the modulation signal generation module 22 generates two sinusoidal electrical signals, which are sent to the phase modulators PMⅠ and PMⅡ. The voltage signals are transmitted by the low-pass filter and sent to the quadrature demodulation module via the ADC. The output difference generated by the quadrature demodulation module is sent to the laser frequency locking control module on one hand, and the laser frequency locking control module generates a control signal for the laser tuning end on the other hand, which serves as the differential output of the gyroscope.

[0071] like Figure 1 The orange and blue portions propagate in the resonant cavity in clockwise and counterclockwise directions, respectively. At the coupler, the light with different numbers of cycles in the clockwise and counterclockwise directions forms multi-beam interference. The light intensity signal formed by this interference is received by the photodetector through the circulator and converted into a digital electrical signal by the analog-to-digital converter, which then enters the digital processing system in the FPGA.

[0072] After signal modulation and quadrature demodulation, two demodulated values ​​proportional to the frequency are obtained, one clockwise and one counterclockwise. The difference between the two demodulated values ​​and the set target value centered on the resonant valley are used as the error signal. After passing through the closed-loop controller, the laser frequency is locked in a closed loop through the tuning end of the laser, so that it is locked at the resonant frequency in the counterclockwise direction. Based on the demodulated output voltage corresponding to the angular velocity sensed by the system, the single and dual closed-loop switching is realized through the Schmitt trigger judgment scheme and automatic reset operation.

[0073] like Figure 2 As shown, the Schmidt-type judgment scheme is specifically as follows: Figure 2A low threshold voltage V was set in set_l and high threshold voltage V set_h To prevent ringing caused by narrowband noise and random noise, a counter Cnt_time is set to prevent pulse noise from causing frequent switching between single and double closed-loop states of the system.

[0074] The scheme works as follows: when the demodulated output voltage exceeds the high threshold voltage V... set_h When the timing reaches Cnt_time, the Flag signal is set to -1. The time division multiplexing and closed-loop switching module 21 uses the analog-to-digital converter ADCⅠ15 to put the variable fiber beam splitter 2 into a 50:50 optical coupler state. The modulation signal generation module 22 uses the analog-to-digital converter ADCⅡ16 to superimpose a sawtooth wave frequency shift signal on the original sine wave modulation signal, and completes the second closed loop on the phase modulator PMⅡ4, so that the system switches from a single closed-loop state to a dual closed-loop state.

[0075] When the demodulated output voltage is less than the low threshold voltage V set_l When the timing reaches Cnt_time, the Flag signal is set to +1. The time division multiplexing and closed-loop switching module 21 uses the analog-to-digital converter ADCⅠ15 to put the variable fiber beam splitter 2 into an optical switch state. The modulation signal generation module 22 only uses the analog-to-digital converter ADCⅡ16 to perform sine wave modulation on the phase modulator PMⅡ4. The system switches from a dual closed-loop state to a single closed-loop state.

[0076] In single-loop mode, the backscattered light corresponding to the two optical paths is collected by analog-to-digital converters ADCⅠ15 and ADCⅡ16 respectively, and the collected values ​​are updated in real time using the moving average. When the system switches to dual-loop mode, the corresponding average is used as an error compensation factor to optimize the quadrature demodulation output in dual-loop mode.

[0077] A closed-loop control method for a resonant micro-optical gyroscope based on a variable fiber beam splitter, wherein the automatic reset method in the closed-loop control is as follows: Figure 3 As shown in the figure, the left side (a) represents the automatic reset operation, the upper figure is the resonance curve, and the lower figure is the quadrature demodulation curve. According to criteria P1 and P2, the resonance curve is divided into five regions, I-V. If the light intensity collected by the ADC is greater than P1 for a certain period of time, the system is considered to have lost lock. The FPGA subtracts one FSR distance from the frequency locking voltage through the laser frequency locking control module. The new frequency locking voltage will fall in any of the five regions, but it can only be relocked if it falls in region I.

[0078] Within region I, a rapid frequency sweep is performed with large step values ​​until the light intensity collected by the ADC is less than P1. At this point, the system is considered to have entered region II, where a more detailed frequency sweep is performed with smaller step values. Only when the light intensity collected by the ADC is less than P2, and the demodulated output is deemed to have entered the linear region by criteria P3 and P4, is the system considered to have entered region II, and closed-loop control begins. If the new frequency-locking voltage falls in other regions, the frequency sweep continues rapidly until the light intensity collected by the ADC is greater than P1 for a certain period of time. At this point, the frequency-locking voltage is reduced by the distance W to ensure that the new frequency-locking voltage falls within region I and completes closed-loop control.

[0079] The right side (b) of the diagram illustrates the linear region determination scheme. Different voltage values ​​are set for criteria P3 and P4. To prevent ringing caused by narrowband noise and random noise, A is the linear region determination symbol. When the light intensity acquired by the ADC is less than P1 but greater than P2, and the demodulation voltage is less than P3, the linear region determination symbol A is set to 0; otherwise, it is set to 1. When the light intensity acquired by the ADC is less than P2, and the demodulation voltage is greater than P4, the linear region determination symbol A is set to 1; otherwise, it is set to 0. A is obtained by taking a pulse on A. d0 , for A d0 Get A by hitting one shot d1 Through A d0 and A d1 The logical operation yields the rising edge of A. up and falling edge A down Only when A is collected up A was collected again later. down Only when the system enters the linear region is it considered to have entered the linear region. Once in the linear region, A is prohibited from being flipped. A is only released again to check for the linear region when the system performs a reset operation.

[0080] The method of dividing the threshold in the linear region of the orthogonal demodulation curve based on the resonance curve and the orthogonal demodulation curve specifically means that, on the output curve, when the linearity does not increase proportionally with the increase of the horizontal axis frequency difference, the low threshold voltage V in the linear region is defined. set_l and high threshold voltage V set_h The corresponding value on the vertical axis.

[0081] An electronic device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the above method.

[0082] A computer-readable storage medium for storing computer instructions that, when executed by a processor, implement the steps of the above-described method.

[0083] The memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the methods described in this invention is intended to include, but is not limited to, these and any other suitable types of memory.

[0084] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired means such as coaxial cable, optical fiber, digital subscriber line, DSL, or wireless means such as infrared, wireless, microwave, etc. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium such as a floppy disk, hard disk, magnetic tape; an optical medium such as a high-density digital video disc, DVD; or a semiconductor medium such as a solid-state disk, SSD, etc.

[0085] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0086] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as execution by a hardware decoding processor, or as execution by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0087] The above provides a detailed description of the resonant micro-optical gyroscope based on a variable fiber beam splitter and its closed-loop control method proposed in this invention. The principles and implementation methods of this invention have been explained. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A resonant micro-optical gyroscope based on a variable fiber optic beam splitter, characterized in that: The resonant micro-optical gyroscope includes a laser (1), a variable fiber beam splitter (2), a phase modulator PMⅠ (3), a phase modulator PMⅡ (4), a circulator Ⅰ (5), a circulator Ⅱ (6), a 95% 2×2 coupler (7), a photodetector PDⅠ (8), a photodetector PDⅡ (9), a whispering resonator cavity (10), a digital-to-analog interface, a digital system, and an analog-to-digital interface; The laser (1) is connected to the variable fiber beam splitter (2) and the digital-to-analog interface respectively. The variable fiber beam splitter (2) is connected to the phase modulator PMⅠ (3) and the phase modulator PMⅡ (4) respectively. The phase modulator PMⅠ (3) is connected to the circulator Ⅰ (5) and the digital-to-analog interface respectively. The phase modulator PMⅡ (4) is connected to the circulator Ⅱ (6) and the digital-to-analog interface respectively. The circulator I (5) is connected to the 95% 2×2 coupler (7) and the photodetector PD I (8) respectively. The circulator II (6) is connected to the 95% 2×2 coupler (7) and the photodetector PD II (9) respectively. The photodetector PD I (8) and the photodetector PD II (9) are both connected to the analog-to-digital interface. The 95% 2×2 coupler (7) is connected to the whispering wall resonator (10); The digital-to-analog interface and the analog-to-digital interface are connected through a digital system; The digital system includes a time-division multiplexing and closed-loop switching module (21). The time-division multiplexing and closed-loop switching module (21) controls the variable fiber beam splitter (2) through the digital-to-analog converter ADCⅠ (15). Based on the demodulated output voltage corresponding to the angular velocity sensed by the system, it realizes single and dual closed-loop switching through Schmitt type judgment scheme and automatic reset operation. The Schmitt type determination scheme specifically involves setting a low threshold voltage. V set_l High threshold voltage V set_h and counter timing time Cnt_time ; When the demodulated output voltage exceeds the high threshold voltage V set_h And the time reached Cnt_time , Flag Signal set to - 1. The time division multiplexing and closed-loop switching module (21) uses the digital-to-analog converter ADCⅠ (15) to put the variable fiber beam splitter (2) into a 50:50 optical coupler state. The modulation signal generation module (22) uses the digital-to-analog converter ADCⅡ (16) to superimpose a sawtooth wave frequency shift signal on the original sinusoidal modulation signal and completes the second closed loop on the phase modulator PMⅡ (4), so that the system switches from a single closed loop state to a double closed loop state. When the demodulated output voltage is less than the low threshold voltage V set_l And the time reached Cnt_time , Flag Signal set to + 1. The time division multiplexing and closed-loop switching module (21) uses the digital-to-analog converter ADCⅠ (15) to put the variable fiber beam splitter (2) into an optical switch state. The modulation signal generation module (22) only uses the digital-to-analog converter ADCⅡ (16) to perform sinusoidal modulation on the phase modulator PMⅡ (4). The system switches from a dual closed-loop state to a single closed-loop state. In the single closed-loop state, the backscattered light corresponding to the two optical paths is collected by the digital-to-analog converter ADCⅠ (15) and the digital-to-analog converter ADCⅡ (16) respectively. The collected values ​​are updated in real time using the sliding average. When the system switches to the dual closed-loop state, the corresponding average is used as the error compensation factor to optimize the quadrature demodulation output in the dual closed-loop state.

2. The resonant micro-optical gyroscope according to claim 1, characterized in that: The digital-to-analog interface includes digital-to-analog converter ADCⅠ (15), digital-to-analog converter ADCⅡ (16), digital-to-analog converter ADCⅢ (17) and digital-to-analog converter ADCⅣ (18). The digital-to-analog converter ADCⅠ (15) is connected to the variable fiber beam splitter (2); The digital-to-analog converter ADCⅡ (16) is connected to the phase modulator PMⅡ (4). The digital-to-analog converter ADCⅢ (17) is connected to the phase modulator PMⅠ (3). The digital-to-analog converter ADCⅣ (18) is connected to the laser (1).

3. The resonant micro-optical gyroscope according to claim 2, characterized in that: The digital system also includes a quadrature demodulation module I (19), a quadrature demodulation module II (20), a modulation signal generation module (22), and a laser frequency locking control module (23). The modulation signal generation module (22) is connected to the digital-to-analog converter ADCⅡ (16) and the digital-to-analog converter ADCⅢ (17) respectively. The demodulated signals output by the quadrature demodulation module I (19) and the quadrature demodulation module II (20) are subtracted to obtain two signals, which are used to realize laser frequency locking and as the output of the gyroscope system. The laser frequency locking control module (23) is connected to the subtraction signal of the quadrature demodulation module I (19) and the quadrature demodulation module II (20).

4. The resonant micro-light gyroscope according to claim 3, characterized in that: The analog-to-digital interface includes a low-pass filter I (11), a low-pass filter II (12), a digital-to-analog converter ADC I (13), and a digital-to-analog converter ADC II (14). The low-pass filter I (11) is connected to the photodetector PDII (9) and the digital-to-analog converter ADCI (13) respectively; the low-pass filter II (12) is connected to the photodetector PDI (8) and the digital-to-analog converter ADCII (14) respectively; The digital-to-analog converter ADCⅠ (13) is connected to the quadrature demodulation module Ⅰ (19); the digital-to-analog converter ADCⅡ (14) is connected to the quadrature demodulation module Ⅱ (20).

5. A closed-loop control method for a resonant micro-optical gyroscope based on a variable fiber optic beam splitter according to any one of claims 1 to 4, characterized in that: The closed-loop control method is specifically as follows: The beam emitted by the laser (1) is split by the variable fiber beam splitter (2), and the split beams are respectively input to the phase modulator PMⅠ (3) and the phase modulator PMⅡ (4) for phase modulation. The beam modulated by phase modulator PMⅠ(3) enters circulator Ⅰ(5), and the beam modulated by phase modulator PMⅡ(4) enters circulator Ⅱ(6). The beams output from circulator Ⅰ(5) and circulator Ⅱ(6) are combined by 95% 2×2 coupler (7) and input to the whispering wall resonator (10). The beam is reflected multiple times in the whispering resonator (10), and the beam reflected from the whispering resonator (10) passes through the 95% 2×2 coupler (7) again and enters the circulator I (5) and the circulator II (6) respectively. The light beam entering the circulator I (5) is converted into a voltage signal by the photodetector PD I (8), and after the high-frequency noise is filtered out by the low-pass filter I (11), it is converted into a digital signal by the digital-to-analog converter ADC I (13) and sent to the quadrature demodulation module I (19). The beam entering the circulator II (6) is converted into a voltage signal by the photodetector PDII (9), and after the high-frequency noise is filtered out by the low-pass filter II (12), it is converted into a digital signal by the digital-to-analog converter ADCII (14) and sent to the quadrature demodulation module II (20). The demodulated signals output by the quadrature demodulation module I (19) and the quadrature demodulation module II (20) are subtracted to obtain two signals. One signal is input to the laser frequency locking control module (23), and the other signal is used as the output of the gyroscope system.

6. The control method for the resonant micro-optical gyroscope according to claim 5, characterized in that: One signal input to the laser frequency locking control module (23) is converted into a digital electrical signal by the digital-to-analog converter ADCⅣ (18). The laser (1) receives the digital electrical signal to adjust the output frequency. Meanwhile, the signal generated by the laser frequency locking control module (23) is sent to the modulation signal generation module (22). The modulation signal generation module (22) generates two sinusoidal electrical signals, which are sent to the phase modulator PMII (4) and the phase modulator PMⅠ (3) respectively through the digital-to-analog converter ADCⅡ (16) and the digital-to-analog converter ADCⅢ (17). The phase modulator PMⅡ (4) and the phase modulator PMⅠ (3) adjust the phase according to the received signal.

7. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method of claim 5 or 6.

8. A computer-readable storage medium for storing computer instructions, characterized in that, When the computer instructions are executed by the processor, they implement the steps of the method of claim 5 or 6.

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