Resonant optical gyroscope based on wide-spectrum active cavity

Abstract

The invention belongs to the technical field of inertial sensors, and discloses a resonant optical gyroscope based on a wide-spectrum active cavity, which adopts the collaborative design of a wide-spectrum light source and an active resonant cavity (integrated EDFA or SOA) to realize closed-loop self-oscillation and angular velocity measurement. The system comprises core units such as a broadband light source, a circulator, a multifunctional integrated chip, a coupler, an active resonant cavity, a photoelectric detector and a signal processing module. When the gyro system rotates spatially, the self-excitation frequency of light in the clockwise direction and the self-excitation frequency of light in the anticlockwise direction in the active resonant cavity generate Sagnac frequency shift, and the frequency difference of the clockwise light and the anticlockwise light is detected through light combination interference to solve the angular velocity of spatial rotation. Loss is compensated through light amplification in the resonant cavity, clockwise and anticlockwise resonant amplified light is generated through self-excitation, the signal-to-noise ratio of output signals of the gyroscope can be remarkably increased, chip-level microminiaturization integration is supported, and the gyroscope is suitable for high-precision inertial navigation, automatic driving and aircraft attitude control.

Description

Technical Field

[0001] This invention belongs to the field of inertial sensor technology, specifically relating to a resonant optical gyroscope based on a broadband active cavity, suitable for high-precision, miniaturized inertial measurement systems. Background Technology

[0002] Resonant optical gyroscopes represent one of the cutting-edge technologies in the field of gyroscopes. Taking resonant fiber optic gyroscopes as an example, they utilize fiber optic rings to form an active resonant cavity as an angle-sensitive element. They detect the frequency difference between clockwise and counterclockwise light caused by the optical Sagnac effect to sense external rotational speed, theoretically satisfying both high precision and small size requirements. Furthermore, resonant optical gyroscopes possess a series of advantages such as high dynamic response, large dynamic range, resistance to electromagnetic interference, and insensitivity to acceleration, making them a crucial direction for the development of inertial gyroscopes towards higher precision and miniaturization. However, traditional broadband light source resonant fiber optic gyroscopes suffer from limitations in resonant cavity loss, which restricts optical signal intensity and reduces the signal-to-noise ratio. The high coupling precision requirements between the external light source and the resonant cavity, coupled with system complexity, result in actual accuracy falling far short of theoretical accuracy.

[0003] Currently, traditional passive cavity broadband light source resonant optical gyroscopes suffer from insufficient theoretical accuracy, yet no solution exists. Given that the power loss in traditional passive cavity broadband light source resonant optical gyroscopes leads to a significant reduction in the theoretical accuracy of the broadband light source resonant cavity, this invention proposes a broadband active cavity-based resonant optical gyroscope, which can effectively solve the problem of reduced theoretical accuracy in broadband light source resonant optical gyroscopes. Summary of the Invention

[0004] Purpose of the invention: A resonant optical gyroscope based on a broadband active cavity is proposed to enhance the optical signal in the resonant cavity, improve the signal-to-noise ratio of the gyroscope signal, and thus improve the performance accuracy of the gyroscope.

[0005] Technical solution: A resonant optical gyroscope based on a broadband active cavity includes: a broadband light source 1, a circulator 2, a multifunctional integrated chip 3, two couplers 4, a Sagnac sensing ring 5, an optical amplification element 6, a detector 7, and a signal processing module 8, wherein... The input of circulator 2 is connected to the optical fiber of broadband light source 1; The output of circulator 2 is optically connected to the input of detector 7; the output of detector 7 is electrically connected to the input of signal processing module 8. The input and output terminals of circulator 2 are connected to the single-port optical fiber of multi-functional integrated chip 3; The first coupler 4, the second coupler 4, the Sagnac sensitive ring 5, and the optical amplification element 6 are connected in series to form an active resonant cavity; The dual-port terminals of the multi-functional integrated chip 3 are connected to two couplers 4 respectively.

[0006] Furthermore, the spectral width of the broadband light source 1 is 20 nm to 100 nm, and the light source is selected from superluminescent diode (SLED), amplified spontaneous emission (ASE), or quantum cascade laser (QCL).

[0007] Furthermore, the multifunctional integrated chip 3 integrates a polarization control module and a Y-waveguide function to eliminate polarization noise and split the broadband light emitted by the light source into two beams in a 1:1 ratio.

[0008] Furthermore, the active resonant cavity 5 is an optical fiber ring cavity or an integrated waveguide cavity, and the cavity material is selected from single-mode optical fiber, silicon-based waveguide, indium phosphide waveguide or lithium niobate waveguide.

[0009] Furthermore, the optical amplification element 6 is a semiconductor optical amplifier (SOA) or an erbium-doped fiber amplifier (EDFA) with a gain dynamic range of 10 dB to 30 dB. The gain can be adjusted by feedback signal to compensate for optical loss in the active resonant cavity. At the same time, by utilizing the synergistic effect of optical amplification and resonance in the active resonant cavity, the system can achieve self-excited oscillation in a wide spectrum.

[0010] Furthermore, the signal processing module 8 uses digital Fourier transform, modulation and demodulation or phase-locked loop to extract frequency difference, and suppresses environmental noise through PID control and filtering algorithms.

[0011] Furthermore, it also includes: adjusting the amplification factor of the optical amplification element 6, specifically: The specific adjustment process requires applying a sweep signal to the multi-functional integrated chip 3, and simultaneously determining the amplification factor of the appropriate optical amplification element 6 that can compensate for optical loss and simultaneously achieve self-excited oscillation by detecting the peak value of the resonance peak on the photodetector 7.

[0012] Furthermore, the amplification factor G of the optical amplification element 6 should satisfy the threshold condition:

[0013] in The coupler transmittance, To compensate for the round-trip loss of the resonant cavity, the broadband optical active resonant cavity system automatically selects the frequency oscillation that satisfies the resonance condition through the gain competition effect, thereby forming a stable resonant signal.

[0014] Beneficial effects: This invention discloses a resonant optical gyroscope based on a broadband active cavity. It utilizes a light source with a wide spectral width (such as a superluminescent diode or an ASE light source) and integrates an optical amplification element (such as an erbium-doped fiber amplifier (EDFA) or a semiconductor optical amplifier (SOA)) inside the resonant cavity to compensate for cavity losses. Simultaneously, by leveraging the synergistic effect of optical amplification and resonance within the active cavity, the system can achieve self-excited oscillation over a wide spectral range. Angular velocity measurement is achieved by detecting the difference in optical oscillation frequencies in the clockwise and counterclockwise directions using interference signals. This approach enhances the optical signal within the resonant cavity, improves the gyroscope signal-to-noise ratio, and contributes to improving the gyroscope's performance accuracy. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the principle of a resonant optical gyroscope based on a broadband active cavity; Explanation of reference numerals in the attached figures: 1 is a broadband light source, 2 is a circulator, 3 is a multi-functional integrated chip, 4 is a coupler, 5 is a Sagnac sensitive ring, 6 is an optical amplification element, 7 is a detector, and 8 is a signal processing module. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0018] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0019] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0021] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0023] This invention employs a collaborative design of a broadband light source and an active resonant cavity (integrated EDFA or SOA) to achieve closed-loop self-excited oscillation and angular velocity measurement. The system includes core units such as a broadband light source, a circulator, a multi-functional integrated chip, a coupler, an active resonant cavity, a photodetector, and a signal processing module. When the gyroscope system rotates in space, the self-excited frequencies of clockwise and counterclockwise light in the active resonant cavity generate a Sagnac frequency shift. The angular velocity of the spatial rotation is calculated by detecting the frequency difference between the clockwise and counterclockwise light through optical amplification within the resonant cavity. This invention significantly improves the signal-to-noise ratio of the gyroscope output signal by compensating for losses through optical amplification within the resonant cavity and generating clockwise and counterclockwise resonant amplified light through self-excitation. It also supports chip-level miniaturization and integration, making it suitable for high-precision inertial navigation, autopilot, and aircraft attitude control.

[0024] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] In a first aspect, the present invention provides a resonant optical gyroscope based on a broadband active cavity, the device comprising: a broadband light source 1, a circulator 2, a multi-functional integrated chip 3, a coupler 4, a Sagnac sensitive ring 5, an optical amplification element 6, a detector 7, and a signal processing module 8. The light emitted from the broadband light source 1 first enters the multifunctional integrated chip 3 through the circulator 2. Inside the multifunctional integrated chip 3, it is split into two beams: clockwise (CW) and counterclockwise (CCW). These two beams then enter the resonant cavity 5 through the coupler 4. The resonant cavity employs a ring structure, allowing the active resonant cavity with a certain free spectral range (FSR) to selectively filter out light signals of specific frequencies. An integrated optical amplification element 6 (such as an EDFA or SOA) amplifies the propagating light signal and compensates for the transmission loss of the resonant cavity. Through the synergistic effect of optical amplification and resonance, the system can automatically select frequencies that meet the resonance conditions within the spectral range of the broadband light source for closed-loop self-oscillation, eliminating the need for an external highly coherent laser. The oscillating CW and CCW beams are then output again through the coupler 4 and enter the multifunctional integrated chip 3 for beam combining, forming an interference light signal. The combined interference light signal is then transmitted to the photodetector 7 via the circulator 2, where the photodetector 7 converts the optical signal into an electrical signal. The signal processing module 8 demodulates the electrical signal and extracts the frequency difference between the CW and CCW direction lights. This frequency difference is proportional to the rotational angular velocity of the system, thereby achieving accurate measurement of the angular velocity.

[0026] Furthermore, the spectral width of the broadband light source 1 is 20 nm to 100 nm, and the light source is selected from superluminescent light-emitting diode (SLED) light source, amplified spontaneous emission (ASE) light source, or quantum cascade laser (QCL).

[0027] Furthermore, the multifunctional integrated chip 3 integrates a polarization control module and a Y-waveguide function to eliminate polarization noise and split the broadband light emitted by the light source into two beams in a 1:1 ratio.

[0028] Furthermore, the active resonant cavity 5 is an optical fiber ring cavity or an integrated waveguide cavity, and the cavity material is selected from single-mode optical fiber, silicon-based waveguide, indium phosphide waveguide or lithium niobate waveguide.

[0029] Furthermore, the optical amplification element 6 is a semiconductor optical amplifier (SOA) or an erbium-doped fiber amplifier (EDFA) with a gain dynamic range of 10dB~30dB. The gain can be adjusted by feedback signal to compensate for optical loss in the resonant cavity. At the same time, by utilizing the synergistic effect of active cavity optical amplification and resonance, the system can achieve self-excited oscillation in a wide spectrum.

[0030] Furthermore, the signal processing module 8 uses digital Fourier transform, modulation and demodulation, or phase-locked loop technology to extract frequency differences, and suppresses environmental noise through PID control, filtering algorithms, etc.

[0031] Secondly, this invention relates to a core component of a resonant optical gyroscope based on a broadband active cavity, namely a broadband active resonant cavity. The device includes a Sagnac sensitive ring 5 and an optical amplification element 6. After constructing the broadband active resonant cavity, the gain of the optical amplification element 6 is adjusted through a feedback signal to compensate for optical losses in the resonant cavity. Simultaneously, the synergistic effect of optical amplification and resonance within the active cavity enables the system to achieve self-excited oscillation over a broadband range. Specifically, the adjustment process requires applying a mode-sweeping signal to the multi-functional integrated chip 3, and simultaneously determining the appropriate amplification factor of the optical amplification element 6 based on the peak-to-peak value of the resonance detected on the photodetector 7 to compensate for optical losses and simultaneously achieve self-excited oscillation. The amplification factor G of the optical amplification element 6 should satisfy a threshold condition.

[0032] in The coupler transmittance, To compensate for the round-trip loss of the resonant cavity, the broadband optical active resonant cavity system automatically selects the frequency oscillation that satisfies the resonance condition through the gain competition effect, thereby forming a stable resonant signal.

[0033] Example 1 This embodiment will further illustrate the use of optical amplification element 6 as a semiconductor optical amplifier (SOA) to construct an SOA-based fiber optic ring active resonant optical gyroscope scheme: like Figure 1As shown, the system includes a broadband light source 1, a circulator 2, a multi-functional integrated chip 3, a coupler 4, a Sagnac sensing ring 5, an optical amplification element 6 (SOA), a detector 7, and a signal processing module 8. The broadband light source 1 has a spectral width of 40 nm and a center wavelength of 1550 nm. The Sagnac sensing ring 5 uses single-mode polarization-maintaining fiber with a length of 500 m. The optical amplification element 6 (SOA) has a gain of 20 dB and a bandwidth of 50 nm. For ease of explanation, see attached... Figure 1 As shown, the system works as follows: The light emitted from the broadband light source 1 first enters the multifunctional integrated chip 3 through the circulator 2. Inside the multifunctional integrated chip 3, it is split into two beams: clockwise (CW) and counterclockwise (CCW). The two beams then enter the resonant cavity 5 through the coupler 4. The resonant cavity adopts a ring structure, allowing the active resonant cavity with a certain free spectral range (FSR) to selectively filter out light signals of specific frequencies. An optical amplification element 6 (SOA) is integrated inside the resonant cavity. The SOA is embedded at the center of the Sagnac sensitive ring 5. The SOA amplifies the propagating light signal and compensates for the transmission loss of the resonant cavity. Under the synergistic effect of optical amplification and resonance, the active resonant cavity can select frequencies that meet the resonance conditions within the spectral range of the broadband light source for closed-loop self-excited oscillation. The oscillating light in the CW and CCW directions is then output through the coupler 4 and enters the multifunctional integrated chip 3 for beam combining to form an interference light signal. The combined interference light signal is transmitted to the photodetector 7 via the circulator 2, where the detector 7 converts the light signal into an electrical signal. The signal processing module 8 demodulates the electrical signal and extracts the frequency difference between the CW and CCW directions. This frequency difference is proportional to the rotational angular velocity of the system, thereby enabling accurate measurement of the angular velocity.

[0034] Example 2 This embodiment will further illustrate the construction of an EFDA-based fiber optic ring active resonant optical gyroscope scheme using optical amplification element 6 as an erbium-doped fiber amplifier (EDFA). like Figure 1 As shown, the system includes a broadband light source 1, a circulator 2, a multi-functional integrated chip 3, a coupler 4, a Sagnac sensing ring 5, an optical amplifier element 6 (EDFA), a detector 7, and a signal processing module 8. The broadband light source 1 has a spectral width of 40 nm and a center wavelength of 1550 nm. The Sagnac sensing ring 5 uses single-mode polarization-maintaining fiber with a length of 500 m. The optical amplifier element 6 (SOA) has a gain of 20 dB and a bandwidth of 50 nm. For ease of explanation, see attached... Figure 1As shown, the system works as follows: The light emitted from the broadband light source 1 first enters the multifunctional integrated chip 3 through the circulator 2. Inside the multifunctional integrated chip 3, it is split into two beams: clockwise (CW) and counterclockwise (CCW). The two beams then enter the resonant cavity 5 through the coupler 4. The resonant cavity adopts a ring structure, allowing the active resonant cavity with a certain free spectral range (FSR) to selectively filter out light signals of specific frequencies. An optical amplifier element 6 (EDFA) is integrated inside the resonant cavity. The EDFA is embedded at the center of the Sagnac sensitive ring 5. The EDFA amplifies the propagating light signal and compensates for the transmission loss of the resonant cavity. Under the synergistic effect of optical amplification and resonance, the active resonant cavity can select frequencies that meet the resonance conditions within the spectral range of the broadband light source for closed-loop self-excited oscillation. The oscillating light in the CW and CCW directions is then output through the coupler 4 and enters the multifunctional integrated chip 3 for beam combining to form an interference light signal. The combined interference light signal is transmitted to the photodetector 7 via the circulator 2, where the detector 7 converts the light signal into an electrical signal. The signal processing module 8 demodulates the electrical signal and extracts the frequency difference between the CW and CCW directions. This frequency difference is proportional to the rotational angular velocity of the system, thereby enabling accurate measurement of the angular velocity.

[0035] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A resonant optical gyroscope based on a broadband active cavity, characterized in that, include: Broadband light source (1), circulator (2), multi-functional integrated chip (3), two couplers (4), Sagnac sensitive ring (5), optical amplification element (6), detector (7), signal processing module (8), among which, The input end of the circulator (2) is connected to the optical fiber of the broadband light source (1); The output of the circulator (2) is optically connected to the input of the detector (7); the output of the detector (7) is electrically connected to the input of the signal processing module (8); The input and output terminals of the circulator (2) are connected to the single-port fiber of the multi-functional integrated chip (3); The first coupler (4), the second coupler (4), the Sagnac sensitive ring (5), and the optical amplification element (6) are connected in series to form an active resonant cavity; The two-port terminals of the multi-functional integrated chip (3) are connected to two couplers (4) respectively.

2. A resonant optical gyroscope based on a broadband active cavity according to claim 1, characterized in that, The broadband light source (1) has a spectral width of 20 nm to 100 nm, and the light source is selected from superluminescent diode (SLED), amplified spontaneous emission (ASE) light source, or quantum cascade laser (QCL).

3. A resonant optical gyroscope based on a broadband active cavity according to claim 1, characterized in that, The multifunctional integrated chip (3) integrates a polarization control module and a Y-waveguide function to eliminate polarization noise and split the broadband light emitted by the light source into two beams at a 1:1 ratio.

4. A resonant optical gyroscope based on a broadband active cavity according to claim 1, characterized in that, The active resonant cavity (5) is an optical fiber ring cavity or an integrated waveguide cavity, and the cavity material is selected from single-mode optical fiber, silicon-based waveguide, indium phosphide waveguide or lithium niobate waveguide.

5. A resonant optical gyroscope based on a broadband active cavity according to claim 1, characterized in that, The optical amplification element (6) is a semiconductor optical amplifier (SOA) or an erbium-doped fiber amplifier (EDFA) with a gain dynamic range of 10dB to 30dB. The gain can be adjusted by feedback signal to compensate for the optical loss in the active resonant cavity. At the same time, by utilizing the synergistic effect of optical amplification and resonance in the active resonant cavity, the system can achieve self-excited oscillation in a wide spectrum.

6. A resonant optical gyroscope based on a broadband active cavity according to claim 1, characterized in that, The signal processing module (8) uses digital Fourier transform, modulation and demodulation or phase-locked loop to extract frequency difference, and suppresses environmental noise through PID control and filtering algorithm.

7. A resonant optical gyroscope based on a broadband active cavity according to claim 5, characterized in that, Also includes: Adjust the amplification factor of the optical amplification element (6), specifically as follows: The specific adjustment process requires applying a sweep signal to the multifunctional integrated chip (3), and simultaneously determining the amplification factor of a suitable optical amplification element (6) that can compensate for optical loss and simultaneously achieve self-excited oscillation based on the peak value of the resonance peak detected on the photodetector (7).

8. A resonant optical gyroscope based on a broadband active cavity according to claim 5, characterized in that, The amplification factor G of the optical amplification element (6) should satisfy the threshold condition: in The coupler transmittance, To compensate for the round-trip loss of the resonant cavity, the broadband optical active resonant cavity system automatically selects the frequency oscillation that satisfies the resonance condition through the gain competition effect, thereby forming a stable resonant signal.

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