Low-cost and high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source

Abstract

The present invention discloses a low-cost, high-precision resonant fiber gyroscope detection system driven by a wide-spectrum light source. The entire system includes an optical system, a signal detection system and a data recorder. The optical system includes a wide-spectrum light source, a spectroscopic device, a coupler, a piezoelectric ceramic phase modulator, a single-mode fiber ring resonator and a photodetector; the signal detection system includes a digital / analog conversion module, an analog / digital conversion module, a digital modulation module, a digital demodulation module, a low-pass filter module and a communication module. In the present invention, piezoelectric ceramics are used as phase modulators instead of lithium niobate electro-optical phase modulators commonly used in fiber gyros, and single-mode fiber ring resonators are used as sensitive elements instead of polarization-maintaining fibers. The signal detection system only needs to provide low-frequency modulation signals and can sample low-frequency signals, which greatly reduces costs and system complexity.

Description

Technical Field

[0001] The invention belongs to the field of inertial navigation, and in particular relates to a low-cost and high-precision resonant optical fiber gyroscope detection system driven by a wide-spectrum light source. Background Art

[0002] Fiber-optic Gyroscope (FOG) is a high-precision angular velocity sensitive element based on the optical Sagnac effect and is widely used in the field of inertial navigation. It mainly includes two types: Interferometric Fiber-optic Gyroscope (IFOG) and Resonator Fiber-optic Gyroscope (RFOG). Among them, IFOG uses a multi-turn fiber ring as its sensitive element, detects the interference light intensity of the clockwise and counterclockwise light beams, and converts the light intensity information into phase information to detect the angular velocity. For a fiber ring of a given diameter, its theoretical sensitivity is positively correlated with the length of the fiber ring. RFOG uses a high-definition fiber ring resonator as its sensitive element, and uses the multi-turn transmission of the light beam in the resonator to enhance the optical Sagnac effect. For a resonator of a given diameter, its theoretical sensitivity is positively correlated with the product of the length of the resonator and the clarity. Therefore, RFOG has the advantages of miniaturization and high sensitivity. However, while increasing the theoretical sensitivity, the resonant cavity also amplifies various optical parasitic effects, including backscattering, polarization effect, and Kerr effect. The existence of these optical parasitic effects deteriorates the long-term stability of RFOG.

[0003] In order to suppress the above-mentioned non-ideal optical parasitic effects, it is proposed to use a wide-spectrum light source instead of a narrow-linewidth laser as a driving light source, and to reduce the influence of optical noise by reducing the coherence of the light source, thereby effectively improving the angular random walk and long-term stability of the gyroscope.

[0004] However, in the resonant fiber gyroscope solution driven by a wide-spectrum light source, the optical path system mostly uses a polarization-maintaining fiber resonant cavity and a lithium niobate electro-optic phase modulator. In order to suppress relative intensity noise (RIN), the signal detection system needs to provide and sample high-frequency signals. The use of these devices greatly increases the cost of the resonant fiber gyroscope driven by a wide-spectrum light source, which is not conducive to the expansion and application of the civilian market. Summary of the invention

[0005] In order to solve the problems in the prior art, the present invention provides a low-cost and high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source.

[0006] The technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention discloses a low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source, comprising an optical system, a signal detection system and a data recorder, wherein the optical system comprises a wide-spectrum light source, a spectroscopic device, a coupler, a piezoelectric ceramic phase modulator, a single-mode fiber ring resonator and a photodetector, and the signal detection system comprises a digital / analog conversion module, an analog / digital conversion module, a digital modulation module, a digital demodulation module, a low-pass filtering module and a communication module;

[0008] The optical splitter comprises at least three ports, the coupler comprises three ports, and the piezoelectric ceramic phase modulator has two ports; the first port of the optical splitter is connected to a wide-spectrum light source, the second port of the optical splitter is connected to the first port of the coupler, the third port of the optical splitter is connected to a photodetector, and the remaining two ports of the coupler are respectively connected to a single-mode fiber ring resonator and a port of the piezoelectric ceramic phase modulator; the other port of the piezoelectric ceramic phase modulator is connected to the single-mode fiber ring resonator; the coupler and the piezoelectric ceramic phase modulator are respectively connected to the same-side input ends of the two couplers of the single-mode fiber ring resonator;

[0009] The digital modulation module generates a sinusoidal wave modulation signal and outputs it to the digital / analog conversion module. The sinusoidal wave modulation signal processed by the digital / analog conversion module acts on the piezoelectric ceramic phase modulator; the photodetector outputs an electrical signal to the analog / digital conversion module, the analog / digital conversion module outputs a digital signal to the digital demodulation module, the digital demodulation module outputs the demodulated digital signal to the low-pass filter module, and the signal filtered by the low-pass filter module is collected by the data recorder through the communication module as the gyroscope signal output of the gyroscope system.

[0010] Furthermore, the spectroscopic device is a circulator or a coupler, and the coupler is a 1×2 coupler or a 2×2 coupler; port 1 of the circulator is connected to the broadband light source, port 2 of the circulator is connected to the first port of the coupler, and port 3 of the circulator is connected to the photodetector.

[0011] In a second aspect, the present invention discloses a detection method of a resonant fiber optic gyroscope of the system, comprising the following steps:

[0012] The digital modulation module generates a sinusoidal wave modulation signal and outputs it to the digital / analog conversion module. The sinusoidal wave modulation signal processed by the digital / analog conversion module acts on the piezoelectric ceramic phase modulator; the broadband light source outputs broadband light to the optical splitter, and the optical splitter outputs broadband light to the coupler. The broadband light is split into a clockwise optical signal and a counterclockwise optical signal with equal optical power in the coupler. The clockwise optical signal enters the single-mode fiber ring resonator and is transmitted multiple times in the resonator. After the multiple-turn transmission, it exits the cavity and is input into the piezoelectric ceramic phase modulator. The piezoelectric ceramic phase modulator outputs the modulated clockwise optical signal to the coupler; the counterclockwise optical signal is first input into the piezoelectric ceramic phase modulator, and the piezoelectric ceramic phase modulator outputs the modulated counterclockwise optical signal to the single-mode fiber ring resonator. The modulated counterclockwise optical signal enters the resonator and is transmitted multiple times in the resonator. The optical signal is transmitted in multiple circles and output from the cavity. After multiple circles of transmission, the counterclockwise optical signal output from the cavity is input into the coupler. The coupler interferes the received counterclockwise optical signal and the clockwise optical signal at the first port of the coupler. The optical signal obtained by interference is output to the optical splitter. The optical splitter outputs the optical signal obtained by interference to the photodetector. The photodetector performs photoelectric conversion on the received optical signal and outputs the electrical signal to the analog / digital conversion module. The analog / digital conversion module outputs the digital signal to the digital demodulation module. The digital demodulation module demodulates the digital signal output by the analog / digital conversion module through a demodulation signal with the same frequency as the signal acting on the piezoelectric ceramic phase modulator, and outputs the demodulated digital signal to the low-pass filter module. The demodulated digital signal after passing through the low-pass filter module is collected by the data recorder through the communication module and output as the gyroscope signal of the gyroscope system.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The low-cost and high-precision resonant fiber gyroscope detection system driven by a wide-spectrum light source provided by the present invention utilizes a single-mode fiber ring resonator instead of a polarization-maintaining fiber ring resonator, and uses a piezoelectric ceramic phase modulator instead of a Y-branch lithium niobate electro-optic phase modulator and other integrated optical devices. The overall optical path is an optical fiber system, and no waveguide structure is used, thereby greatly reducing costs.

[0015] The invention provides a low-cost and high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source. The signal detection system provides a low-frequency modulation signal and samples the low-frequency signal, which reduces the complexity of the system and also reduces the cost, thus facilitating engineering applications.

[0016] The low-cost and high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source provided by the present invention utilizes a wide-spectrum light source to effectively reduce optical parasitic effects, while the system maintains excellent reciprocity, thereby greatly improving detection accuracy and stability.

[0017] In the low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source provided by the present invention, both clockwise and counterclockwise light pass through the phase modulator only once, which is manifested in the absence of a secondary modulation effect of a Y-branch lithium niobate electro-optic phase modulator in mathematical derivation and in the absence of a secondary expansion of the spectrum in physical analysis, and the theoretical analysis is simple and clear.

[0018] The low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source provided by the present invention has a coupler + piezoelectric ceramic phase modulator structure with lower loss than the Y-branch lithium niobate phase modulator, and the same length of single-mode optical fiber has lower loss than the polarization-maintaining optical fiber. The former will increase the light intensity reaching the photodetector and carry more energy for speed information; the latter will reduce the loss of the resonant cavity, which is conducive to the establishment of a higher-definition resonant cavity. The theoretical sensitivity of the fiber optic gyroscope constrained by shot noise shows that the greater the light intensity reaching the photodetector, the higher the clarity of the resonant cavity, and the higher the theoretical sensitivity of the fiber optic gyroscope, which is conducive to the development of RFOG towards higher precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source;

[0020] Figure 2 It is a schematic diagram of the normalized demodulation curve output after signal demodulation;

[0021] Figure 3 It is a schematic diagram of the relationship between the clockwise and counterclockwise resonant frequencies of a resonant fiber gyroscope driven by a wide-spectrum light source when it rotates;

[0022] Figure 4 It is a schematic diagram of a specific implementation case of a low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source;

[0023] Figure 5 This is a 1-hour static test data chart of a low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source;

[0024] Figure 6 It is an Allen variance analysis diagram that matches the 1-hour static test data of a low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source.

[0025] In the figure: 1. Broad-spectrum light source; 2. circulator; 3. coupler; 4. piezoelectric ceramic phase modulator; 5. single-mode fiber ring resonator; 6. photodetector; 7. digital modulation module; 8. digital / analog conversion module; 9. analog / digital conversion module; 10. digital demodulation module; 11. low-pass filter module; 12. communication module; 13. data recorder. DETAILED DESCRIPTION

[0026] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0027] like Figure 1 As shown, the present invention provides a low-cost and high-precision resonant fiber gyroscope detection system driven by a wide-spectrum light source. The system includes an optical system, a signal detection system and a data recorder 13. The optical system includes a wide-spectrum light source 1, a circulator 2, a coupler 3, a single-mode fiber ring resonator 5, a piezoelectric ceramic phase modulator 4 and a photodetector 6. The signal detection system includes a digital / analog conversion module 8, an analog / digital conversion module 9, a digital modulation module 7, a digital demodulation module 10, a low-pass filtering module 11 and a communication module 12.

[0028] The specific connections between the gyroscope detection systems are as follows: port 1 of the circulator 2 is connected to the wide-spectrum light source 1, port 2 of the circulator 2 is connected to the first port of the coupler 3, and port 3 of the circulator 2 is connected to the photodetector 6; the remaining two ports of the coupler are respectively connected to the single-mode fiber ring resonator 5 and one port of the piezoelectric ceramic phase modulator 4; the other port of the piezoelectric ceramic phase modulator 4 is connected to the fiber ring resonator 5; the coupler and the piezoelectric ceramic phase modulator are respectively connected to the same-side input ends of the two couplers of the single-mode fiber ring resonator.

[0029] A sine wave modulation signal generated by the digital modulation module 7 acts on the piezoelectric ceramic phase modulator after passing through the digital / analog conversion module 8; the photodetector 6 outputs the optical signal as an electrical signal, which is sampled by the analog / digital conversion module 9 and then synchronously demodulated in the digital demodulation module 10, and the frequency of the demodulated signal is the same as the frequency of the modulation signal applied to the piezoelectric ceramic phase modulator 4. The demodulated output signal of the digital demodulation module 10 passes through the low-pass filter module 11, and is collected by the data recorder 13 through the communication module 12 as the gyro signal output of the gyro system.

[0030] like Figure 4 As shown, the specific working process of the above optical gyroscope detection system is as follows:

[0031] The digital modulation module 7 generates a low-frequency sinusoidal wave modulation signal, which acts on the piezoelectric ceramic phase modulator after passing through the digital / analog conversion module 8; the wide-spectrum light output by the wide-spectrum light source 1 passes through the circulator 2 and is split into two clockwise and counterclockwise optical signals with equal optical power at the coupler 3. The light transmitted in the clockwise direction enters the resonant cavity from the coupler port of the single-mode fiber ring resonator 5 and is transmitted in the cavity for multiple turns. The optical signal after exiting the cavity is modulated by the piezoelectric ceramic phase modulator 4; while the light transmitted in the counterclockwise direction is first modulated by the piezoelectric ceramic phase modulator 4, then enters the single-mode fiber ring resonator 5, and is transmitted in the cavity for multiple turns before exiting the cavity. The two beams of light after exiting the cavity interfere at the input port of the coupler 3, and the interfered light goes from port 2 of the circulator to port 3 of the circulator, and then undergoes photoelectric conversion in the photodetector 6. The output signal of the photodetector passes through the analog / digital conversion module 9 and enters the digital demodulation module 10 for synchronous demodulation. The demodulated output passes through the low-pass filter module 11 and is collected by the data recorder 13 through the communication module 12 as the gyro signal output of the gyro system.

[0032] The design of the low-cost and high-precision resonant fiber gyroscope detection system driven by a wide-spectrum light source of the present invention does not need to use a Y-branch phase modulator and a polarization-maintaining fiber like the previous gyroscope detection systems. The present invention only uses all-fiber devices, only the circulator is a polarization-maintaining fiber structure and the others are single-mode fibers. There are no additional waveguide optical devices in the system, thereby reducing the cost of the gyroscope. At the same time, due to the bandwidth limitation of the piezoelectric ceramic phase modulator, the present invention does not need to design a high-frequency circuit, which objectively reduces the complexity of the circuit. All of these will greatly accelerate the process of practical application of the resonant fiber gyroscope.

[0033] The present invention uses a low-cost single-mode fiber ring resonator 5 instead of a polarization-maintaining fiber resonator, and uses a piezoelectric ceramic phase modulator 4 instead of a lithium niobate electro-optical phase modulator commonly used in fiber optic gyroscopes, so that a low-cost optical path can be achieved. That is, the circulator, coupler, piezoelectric ceramic phase modulator, and single-mode fiber ring resonator are all composed of optical fibers. The present invention is an all-optical solution and does not use waveguide optical devices such as integrated optical Y branches.

[0034] In a specific embodiment of the present invention, the frequency of the signal applied to the piezoelectric ceramic phase modulator is relatively low, so an analog / digital conversion module and a digital / analog conversion module with a relatively low sampling rate can be used, so that the signal detection system can also use low-cost circuits, including but not limited to digital circuit boards with FPGA, STM32, Arduino, and DSP as digital processing units. The digital modulation and digital demodulation modules use sinusoidal wave modulation-demodulation technology, which has a simple structure and occupies few resources.

[0035] The single-mode fiber ring resonator in this scheme is a single-mode transmission fiber ring resonator, and is connected to the coupler and piezoelectric ceramic phase modulator using a transmission symmetrical connection method in which the clockwise and counterclockwise optical signals share the input and output ports, which is extremely beneficial to improving the signal-to-noise ratio of the gyro output; the modulation signal applied to the piezoelectric ceramic phase modulator is optimized to obtain the maximum demodulation slope and improve the detection accuracy. The modulation signal applied to the piezoelectric ceramic phase modulator is a low-frequency modulation signal, using a low-cost low-frequency circuit; the frequency of the low-frequency modulation signal is less than the bandwidth of the piezoelectric ceramic phase modulator, which is usually about tens of kHz.

[0036] In a specific embodiment of the present invention, the circulator can be replaced by a coupler, and the coupler can be used in either a 1×2 mode or a 2×2 mode. The physical analysis model and mathematical derivation process of the present invention are different from the existing resonant fiber gyroscope solution driven by a wide-spectrum light source. The current detection system uses an optical path of a Y-branch lithium niobate electro-optical phase modulator structure. The clockwise and counterclockwise optical paths undergo two opposite modulation effects respectively, but only the light modulated for the first time will pass through the resonant cavity, and the light modulated for the second time will have a divergent effect on the original signal and will not enhance the effective signal; in the structure of the coupler + piezoelectric ceramic phase modulator of the present invention, only the light that first passes through the piezoelectric ceramic phase modulator and then passes through the resonant cavity in the clockwise and counterclockwise optical paths will change the incident light frequency of the resonant cavity, and the laser frequency of the other path that first passes through the resonant cavity and then passes through the piezoelectric ceramic phase modulator remains unchanged in the resonant cavity. Compared with the previous structure, both the clockwise and counterclockwise light pass through the phase modulator only once, and the optical frequency will not be expanded twice. Parameters such as the optimal modulation frequency and demodulation slope are greatly different from those of the previous structure.

[0037] like Figure 2 As shown in FIG. 1 , the demodulation curve of the output signal of the digital demodulation module of the signal detection system of the low-cost and high-precision resonant fiber gyroscope driven by a wide-spectrum light source is given. It can be seen from the demodulation curve that when the system is stationary, the demodulation output is 0. When the system rotates, that is, when there is a resonant frequency difference between the clockwise and counterclockwise light beams, the demodulation output begins to change. By calibrating the relationship between the demodulation output and the actual angular velocity of the system rotation, the angular velocity of the system rotation can be obtained according to the demodulation output value.

[0038] like Figure 3As shown, it gives a schematic diagram of the relationship between the clockwise and counterclockwise resonant frequencies of the resonant optical gyroscope when it is stationary and rotating. When the system is stationary, the resonant frequencies of the clockwise and counterclockwise light beams are exactly the same, and the spectra of the two completely overlap. At this time, the light intensity obtained by interference is the largest, as shown by the dotted line; when the system rotates, the resonant frequencies of the clockwise and counterclockwise light beams move in opposite directions. At this time, the light intensity decreases after the clockwise and counterclockwise light interferes. The greater the rotation speed, the greater the degree of light intensity reduction. The present invention detects angular velocity by detecting changes in light intensity.

[0039] like Figure 4 As shown, it is a real-time example of a low-cost, high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source. The present invention uses a piezoelectric ceramic phase modulator as an optical phase modulator and a single-mode fiber ring resonator as a core sensitive element. The signal detection system is coded on an FPGA-based development platform and a personal computer is used as a data recorder.

[0040] like Figure 5 As shown in the figure, it is the 1-hour static test data of the low-cost and high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source. A single-mode wide-spectrum light source with a wide-spectrum power of about 5mW is selected. The length, radius and clarity of the resonant cavity are 39m, 6.5cm and 58.5 respectively. The sampling rate of the data recorder is 100Hz. The blue curve plots the unprocessed gyroscope data, and the red curve is the gyroscope data after 100s sliding average, and its variance is about 0.0978° / h.

[0041] like Figure 6 As shown in the figure, it is an Allan variance analysis matched with 1-hour static test data of a low-cost, high-precision resonant fiber gyroscope detection system driven by a wide-spectrum light source. The blue and red curves describe the non-overlapping and overlapping Allan variance curves, respectively. The indicator of the gyroscope white noise level is the angular random walk (ARW), whose value is 0.0219° / √h; the indicator of the gyroscope stability is the bias instability (BI), whose value is better than 0.031° / h. According to the classification of gyroscope performance indicators, the gyroscope reaches near-navigation-level performance indicators. Due to its low-cost advantage, it can be widely used in robotics, intelligent driving, precision medical equipment, aerospace, missile guidance and other fields. By optimizing the single-mode fiber resonant cavity, such as increasing the length of the resonant cavity and improving the clarity of the resonant cavity, it can fully achieve navigation-level performance indicators. In summary, it has broad application prospects.

[0042] The above-mentioned embodiments only express several implementation modes of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A low-cost and high-precision resonant fiber optic gyroscope detection system driven by a wide-spectrum light source, characterized in that: It includes an optical system, a signal detection system and a data recorder. The optical system includes a wide-spectrum light source, a spectroscopic device, a coupler, a piezoelectric ceramic phase modulator, a single-mode fiber ring resonator and a photodetector. The signal detection system includes a digital / analog conversion module, an analog / digital conversion module, a digital modulation module, a digital demodulation module, a low-pass filter module and a communication module. The optical splitter comprises at least three ports, the coupler comprises three ports, and the piezoelectric ceramic phase modulator has two ports; the first port of the optical splitter is connected to a wide-spectrum light source, the second port of the optical splitter is connected to the first port of the coupler, the third port of the optical splitter is connected to a photodetector, and the remaining two ports of the coupler are respectively connected to a single-mode fiber ring resonator and a port of the piezoelectric ceramic phase modulator; the other port of the piezoelectric ceramic phase modulator is connected to the single-mode fiber ring resonator; the coupler and the piezoelectric ceramic phase modulator are respectively connected to the same-side input ends of the two couplers of the single-mode fiber ring resonator; The digital modulation module generates a sinusoidal wave modulation signal and outputs it to the digital / analog conversion module. The sinusoidal wave modulation signal processed by the digital / analog conversion module acts on the piezoelectric ceramic phase modulator. The photoelectric detector outputs an electrical signal to the analog / digital conversion module, the analog / digital conversion module outputs a digital signal to the digital demodulation module, the digital demodulation module outputs the demodulated digital signal to the low-pass filter module, and the signal filtered by the low-pass filter module is collected by the data recorder through the communication module as the gyroscope signal output of the gyroscope system.

2. The system according to claim 1, characterized in that The digital demodulation module demodulates the digital signal output by the analog / digital conversion module through a demodulation signal, and the frequency of the demodulation signal is the same as the frequency of the signal acting on the piezoelectric ceramic phase modulator.

3. The system according to claim 1, characterized in that The signal acting on the piezoelectric ceramic phase modulator is a low-frequency modulation signal, and the frequency of the low-frequency modulation signal is less than the bandwidth of the piezoelectric ceramic phase modulator.

4. The system according to claim 1, characterized in that The single-mode fiber ring resonator is a single-mode transmission fiber ring resonator, and is connected to a coupler and a piezoelectric ceramic phase modulator by a transmission symmetrical connection method in which clockwise and counterclockwise optical signals share input and output ports.

5. The system according to claim 1, characterized in that The digital modulation module adopts a sine wave modulation technology, and the digital demodulation module adopts a sine wave demodulation technology.

6. The system according to claim 1, characterized in that The optical splitter is a circulator or a coupler, and the coupler is a 1×2 coupler or a 2×2 coupler; port 1 of the circulator is connected to a wide-spectrum light source, port 2 of the circulator is connected to a first port of the coupler, and port 3 of the circulator is connected to a photodetector.

7. A method for detecting a resonant fiber optic gyroscope of the system according to claim 2, characterized in that: The following steps are involved: The digital modulation module generates a sinusoidal wave modulation signal and outputs it to the digital / analog conversion module. The sinusoidal wave modulation signal processed by the digital / analog conversion module acts on the piezoelectric ceramic phase modulator; the wide-spectrum light source outputs wide-spectrum light to the spectroscopic device, and the spectroscopic device outputs wide-spectrum light to the coupler. The wide-spectrum light is split into a clockwise light signal and a counterclockwise light signal with equal optical power in the coupler. The clockwise light signal enters the single-mode optical fiber ring resonator and is transmitted multiple times in the resonator. After the multiple-turn transmission, it exits the cavity and is input into the piezoelectric ceramic phase modulator. The piezoelectric ceramic phase modulator outputs the modulated clockwise light signal to the coupler; The counterclockwise optical signal is first input into the piezoelectric ceramic phase modulator, and the piezoelectric ceramic phase modulator outputs the modulated counterclockwise optical signal to the single-mode fiber ring resonant cavity. The modulated counterclockwise optical signal enters the resonant cavity, and is transmitted multiple times in the resonant cavity and exits the cavity. The counterclockwise optical signal exiting the cavity after multiple-circle transmission is input into the coupler. The coupler interferes the received counterclockwise optical signal and the clockwise optical signal at the first port of the coupler, and the optical signal obtained by interference is output to the optical splitter. The optical splitter outputs the optical signal obtained by interference to the photodetector. The photodetector performs photoelectric conversion on the received optical signal and outputs an electrical signal to the analog / digital conversion module. The analog / digital conversion module outputs a digital signal and outputs it to the digital demodulation module. The digital demodulation module demodulates the digital signal output by the analog / digital conversion module through a demodulation signal having the same frequency as the signal acting on the piezoelectric ceramic phase modulator, and outputs the demodulated digital signal to the low-pass filter module. The demodulated digital signal after passing through the low-pass filter module is collected by the data recorder through the communication module and output as the gyro signal of the gyro system.

Images