Silicon-based cavity optical power system gyroscope decoupling device based on FSR multiple modes

Abstract

The invention discloses a silicon-based cavity optical power system gyroscope decoupling device based on FSR multiple modes. The silicon-based cavity optical power system gyroscope decoupling device comprises a pump light system, a probe light system and a silicon-based cavity optical power micro-hemisphere gyroscope chip. Pump laser passes through a light polarization controller A to obtain laser in any polarization state, and the laser is coupled into a micro-hemisphere cavity of the silicon-based cavity light force micro-hemisphere gyroscope chip through a driving optical fiber; emergent light enters a photoelectric detector A, and an output signal of the photoelectric detector A is connected with a computer A through a data collector A; the detection laser passes through the light polarization controller B to obtain laser in any polarization direction, and the laser enters the micro-hemisphere cavity through coupling of the detection optical fiber; emergent light enters a photoelectric detector B, and electric signals output by the photoelectric detector B respectively enter a frequency spectrograph and a data acquisition unit B; according to the invention, the driving mode and the detection mode of the cavity can be independently decoupled by using the optical-mechanical coupling effect principle of the cavity optical power system and the independence between the harmonic peak offsets in the optical spectrum and the mechanical spectrum.

Description

Technical Field

[0001] The present invention belongs to the technical field of decoupling detection of resonant gyroscopes, and particularly relates to a decoupling device for a silicon-based cavity optomechanical system gyroscope based on FSR multi-mode. Background Art

[0002] Gyroscope detection technology is a technology for measuring the angular velocity of a moving object, and it has wide application requirements in military fields such as aerospace spacecraft, unmanned aerial vehicles, micro-miniature guided ammunitions, etc., and in civilian fields such as driverless cars, consumer electronics, geodetic surveying, deep sea / geological exploration, vibration detection, attitude stabilization, etc. Gyroscopes mainly include various types such as tuning fork gyroscopes, vibrating ring gyroscopes, piezoelectric vibrating gyroscopes, frame gyroscopes, microhemispherical resonant gyroscopes, etc. However, traditional gyroscope detection technology is difficult to achieve independent decoupling of the driving mode and the detection mode of the microhemispherical resonator. This is mainly because the shift of a single resonance peak of the microhemispherical cavity is caused by the combined action of the driving mode vibration signal and the detection mode vibration signal.

[0003] In recent years, as a new concept of high-performance micro-nano structure, the silicon-based cavity optomechanical system has developed vigorously in the directions of basic physical properties, typical micro-nano sensing applications, etc. This new type of micro-nano cavity structure simultaneously has optical cavity modes and mechanical oscillation modes at the micro-nano scale. The gyroscope detection technology based on the silicon-based cavity optomechanical system is a technology for detecting angular velocity by using the strong coupling interaction effect between the optical cavity mode and the mechanical oscillation mode. However, there is no detection method for independently decoupling the driving mode and the detection mode in the existing technology. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a decoupling device for a silicon-based cavity optomechanical system gyroscope based on FSR multi-mode. The present invention utilizes the optomechanical coupling effect principle of the cavity optomechanical system and the independence between the shifts of each resonance peak in the optical spectrum and the mechanical spectrum to independently decouple the driving mode and the detection mode of the cavity, and then realizes angular velocity measurement.

[0005] The purpose of the present invention is achieved by the following technical solutions: A decoupling device for a silicon-based cavity optomechanical system gyroscope based on FSR multi-mode, including a pump light system, a probe light system, and a silicon-based cavity optomechanical microhemisphere gyroscope chip and a high-precision angular velocity turntable located in a vacuum system;

[0006] The high-precision angular velocity turntable is arranged below the silicon-based cavity optomechanical microhemisphere gyroscope chip, and the high-precision angular velocity turntable works under the drive of a single-axis turntable controller, applying an external angular velocity to the silicon-based cavity optomechanical microhemisphere gyroscope chip;

[0007] The pump light system includes a high-power laser source, an optical polarization controller A, a photodetector A, a data collector A, and a computer A; the high-power laser source is connected to the optical polarization controller A, and the pump laser emitted by the high-power laser source enters the optical polarization controller A through an optical fiber to obtain a laser with an arbitrary polarization state. The laser with an arbitrary polarization state is coupled into the microhemispherical cavity of the silicon-based cavity optomechanical microhemispherical gyroscope chip in the vacuum system through a driving optical fiber to excite the driving mode of the cavity. The outgoing light of the microhemispherical cavity carrying multi-mode information enters the photodetector A, and the photodetector A converts the optical signal into an electrical signal. The electrical signal output by the photodetector A enters the data collector A, and the data collector A is connected to the computer A; the high-power laser source outputs by sweeping frequency near a single FSR characteristic frequency, and an optical resonance characteristic transmission curve is obtained in the computer A.

[0008] The detection light system includes a low-power laser source, an optical polarization controller B, a photodetector B, a spectrum analyzer, a data collector B, and a computer B; the low-power laser source is connected to the optical polarization controller B, and the detection laser emitted by the low-power laser source enters the optical polarization controller B through an optical fiber to obtain a laser with an arbitrary polarization direction. The laser with an arbitrary polarization direction is coupled into the microhemispherical cavity of the silicon-based cavity optomechanical microhemispherical gyroscope chip in the vacuum system through a detection optical fiber; the detection laser emitted from the microhemispherical cavity carrying the optomechanical coupling signal enters the photodetector B, and the electrical signals output by the photodetector B enter the spectrum analyzer and the data collector B respectively; the computer B reads and analyzes the time-domain information of the angular velocity, and the spectrum analyzer reads and analyzes the frequency-domain information of the angular velocity.

[0009] In the optical resonance characteristic transmission curve, the frequency corresponding to the peak value of the single FSR resonance peak with the highest coupling efficiency in the optical resonance characteristic transmission curve is selected as the frequency of the pump laser, and this resonance peak is defined as the driving peak; the frequency corresponding to the peak value of the single FSR resonance peak with the highest coupling efficiency except the driving peak in the optical resonance characteristic transmission curve is selected as the frequency of the detection laser, and this single resonance peak is defined as the detection peak.

[0010] Both the driving optical fiber and the detection optical fiber are U-shaped optical fibers, and the bottom surfaces of the two U-shaped optical fibers are close to the silicon-based cavity optomechanical microhemispherical gyroscope chip; the included angle between the connection lines of the center points of the two U-shaped optical fibers and the center point of the silicon-based cavity optomechanical microhemispherical gyroscope chip is 45°.

[0011] The beneficial effects of the present invention are: (1) The decoupling device of the present invention includes a pump light system that emits high-power laser and a detection light system that emits low-power laser for detection, which can achieve independent decoupling of the driving mode and the detection mode.

[0012] (2) In the optical resonance characteristic transmission curve of the present invention, different resonance peaks are selected as the driving peak and the detection peak. There is a certain wavelength interval between the driving peak and the detection peak, which can ensure that the representations of the driving mode and the detection mode do not interfere with each other. Description of the Drawings

[0013] Figure 1 is the architecture diagram of the decoupling device of the silicon-based cavity optomechanical system gyroscope based on FSR multi-mode provided by the present invention;

[0014] Figure 2 is the schematic diagram of the optical resonance characteristic transmission curve of the microhemispherical resonator of the present invention;

[0015] Figure 3 is the schematic diagram of the mechanical oscillation signal of the microhemispherical resonator of the present invention;

[0016] Figure 4 is the schematic diagram of the relative positions of the driving optical fiber and the detection optical fiber provided by the present invention with respect to the microhemispherical resonator. Detailed Embodiments

[0017] The technical solution of the present invention will be further described below with reference to the drawings.

[0018] As Figure 1 shown, a decoupling device of a silicon-based cavity optomechanical system gyroscope based on FSR (Free Spectral Range) multi-mode according to the present invention includes a pump light system, a detection light system, and a silicon-based cavity optomechanical microhemispherical gyroscope chip and a high-precision angular velocity turntable located in a vacuum system; the vacuum system refers to a vacuum chamber and devices such as optical waveguide interfaces and electrical interfaces configured on its side, which is a device that provides a vacuum environment for measurement, can reduce the influence of environmental noise and air damping on the test results, and perform fiber coupling and electrical tests in a vacuum environment.

[0019] The high-precision angular velocity turntable is arranged below the silicon-based cavity optomechanical microhemispherical gyroscope chip and operates under the drive of a single-axis turntable controller to apply an external angular velocity to the silicon-based cavity optomechanical microhemispherical gyroscope chip.

[0020] The microhemispherical cavity is a hemispherical shell with an outer diameter of approximately 120 microns and a shell thickness of approximately 2 microns fabricated by two-photon 3D printing technology. The printing material used is IP-Dip2 with a refractive index of 1.547@589nm, 20°C. The edge of the spherical shell is a circular lip outer edge structure with a width of 5 microns and a thickness of 2 microns. In actual processing and applications, the surface smoothness and thickness uniformity of the microhemispherical cavity with the circular lip outer edge structure ensure the optical performance requirements of the microcavity, as well as the practicality and feasibility of processing. Based on the above microhemispherical cavity structure, for the silicon-based cavity optomechanical microhemispherical gyroscope chip, there is a support pillar with a diameter of 5 microns and a length of 20 microns under each microhemispherical shell, and a square base with a side length of 30 microns and a height of 2 microns is used as the structural support. Each cavity is spaced 200 microns apart and is arranged in a processing area of 2.5 cm × 2.5 cm.

[0021] The pump light system includes a high-power laser source, a polarization controller A, a photodetector A, a data collector A, and a computer A. The high-power laser source is connected to the polarization controller A. The pump laser emitted by the high-power laser source enters the polarization controller A through an optical fiber to obtain laser with an arbitrary polarization state. The laser with an arbitrary polarization state is coupled into the microhemispherical cavity of the silicon-based cavity optomechanical microhemispherical gyroscope chip in the vacuum system through a driving optical fiber to excite the driving mode of the cavity. The outgoing light of the microhemispherical cavity carrying multimode information enters the photodetector A, and the photodetector A converts the optical signal into an electrical signal. The electrical signal output by the photodetector A enters the data collector A, and the data collector A is connected to the computer A. The high-power laser source sweeps the frequency output near a single FSR characteristic frequency, and an optical resonance characteristic transmission curve is obtained in the computer A, as Figure 2 shown. The optical resonance characteristic transmission curve characterizes the coupling efficiency between the optical fiber and the cavity, and the coupling efficiency can be maximized by adjusting the relative position of the optical fiber and the cavity.

[0022] The probe light system includes a low-power laser source, a polarization controller B, a photodetector B, a spectrum analyzer, a data collector B, and a computer B. The low-power laser source is connected to the polarization controller B. The probe laser emitted by the low-power laser source enters the polarization controller B through an optical fiber to obtain laser with an arbitrary polarization direction. The laser with an arbitrary polarization direction is coupled into the microhemispherical cavity of the silicon-based cavity optomechanical microhemispherical gyroscope chip in the vacuum system through a probe optical fiber. The probe laser emitted from the microhemispherical cavity carrying the optomechanical coupling signal enters the photodetector B, and the electrical signal output by the photodetector B enters the spectrum analyzer and the data collector B respectively. The computer B reads and analyzes the time-domain information of the angular velocity, and the spectrum analyzer reads and analyzes the frequency-domain information of the angular velocity.

[0023] The pump light system emits high-power laser to excite the driving mode of the cavity; then, an angular velocity is applied to the silicon-based cavity optomechanical microhemispherical gyroscope chip by a high-precision angular velocity turntable. Under the Coriolis effect, the driving mode induces the detection mode, and then the low-power laser emitted by the probe light system is used to detect the detection mode generated by the cavity.

[0024] The power signal change caused by the displacement of the gyroscope detection mode due to the angular velocity of the high-precision angular velocity turntable can be observed, as Figure 3 shown. By changing the angular velocity of the high-precision angular velocity turntable and observing the corresponding changes with a spectrum analyzer, information such as the zero-bias stability, angle random walk, and angular velocity measurement range of the detection axis of the microhemispherical resonator gyroscope can be obtained.

[0025] There are multiple resonant modes in the optical resonance curve, and the wavelength interval between two adjacent resonant modes is the FSR. In the optical resonance characteristic transmission curve, the frequency corresponding to the peak value of a single FSR resonant peak with the highest coupling efficiency in the optical resonance characteristic transmission curve is selected as the frequency of the pump laser, and this resonant peak is defined as the driving peak; the frequency corresponding to the peak value of a single FSR resonant peak with the highest coupling efficiency except the driving peak in the optical resonance characteristic transmission curve is selected as the frequency of the probe laser, and this single resonant peak is defined as the detection peak. Two different resonant modes in the optical resonance curve are respectively defined as the driving peak and the detection peak to characterize the changes of the driving mode and the detection mode, and further distinguish the driving mode and the detection mode to avoid crosstalk in the characterization.

[0026] Both the driving optical fiber and the probe optical fiber are U-shaped optical fibers, and the bottom surfaces of the two U-shaped optical fibers are close to the silicon-based cavity optomechanical microhemispherical gyroscope chip; the included angle between the connecting lines of the centers of the two U-shaped optical fibers and the center point of the silicon-based cavity optomechanical microhemispherical gyroscope chip is 45°. The preparation device of the U-shaped optical fiber consists of a fiber taper machine, an observation table, a flame nozzle, a hydrogen-oxygen generator, an ultraviolet lamp, and a metal fixing bracket. After the prepared U-shaped optical fiber is cooled and shaped, it is fixed in the groove of the metal fixing bracket with UV glue. The two U-shaped optical fibers and the silicon-based cavity optomechanical microhemispherical gyroscope chip are respectively fixed on three electric displacement stages in the vacuum system. In this embodiment, the relative positions of the driving optical fiber and the probe optical fiber with respect to the silicon-based cavity optomechanical microhemispherical gyroscope chip are as Figure 4 (a) and 4(b) shown, and the chip is attached to the two U-shaped optical fibers through the electric displacement stage.

[0027] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations without departing from the essence of the present invention based on the technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the present invention.

Claims

1. A decoupling device for a silicon-based cavity optomechanical system gyroscope based on FSR multi-mode, characterized in that, It includes a pump light system, a probe light system, a silicon-based cavity optomechanical microhemispherical gyroscope chip and a high-precision angular velocity turntable located in a vacuum system; The high-precision angular velocity turntable is arranged below the silicon-based cavity optomechanical microhemispherical gyroscope chip. The high-precision angular velocity turntable works under the drive of a single-axis turntable controller, applying an external angular velocity to the silicon-based cavity optomechanical microhemispherical gyroscope chip; The pump light system includes a high-power laser source, an optical polarization controller A, a photodetector A, a data collector A, and a computer A; the high-power laser source is connected to the optical polarization controller A. The pump laser emitted by the high-power laser source enters the optical polarization controller A through an optical fiber to obtain a laser with an arbitrary polarization state. The laser with an arbitrary polarization state is coupled into the microhemispherical cavity of the silicon-based cavity optomechanical microhemispherical gyroscope chip in the vacuum system through a driving optical fiber to excite the driving mode of the cavity; the outgoing light of the microhemispherical cavity carrying multi-mode information enters the photodetector A, and the photodetector A converts the optical signal into an electrical signal; the electrical signal output by the photodetector A enters the data collector A, and the data collector A is connected to the computer A; the high-power laser source sweeps the frequency output near a single FSR characteristic frequency, and an optical resonance characteristic transmission curve is obtained in the computer A; The probe light system includes a low-power laser source, an optical polarization controller B, a photodetector B, a spectrometer, a data collector B, and a computer B; the low-power laser source is connected to the optical polarization controller B. The probe laser emitted by the low-power laser source enters the optical polarization controller B through an optical fiber to obtain a laser with an arbitrary polarization direction. The laser with an arbitrary polarization direction is coupled into the microhemispherical cavity of the silicon-based cavity optomechanical microhemispherical gyroscope chip in the vacuum system through a probe optical fiber; the probe laser emitted from the microhemispherical cavity carrying the optomechanical coupling signal enters the photodetector B, and the electrical signal output by the photodetector B enters the spectrometer and the data collector B respectively; the computer B reads and analyzes the time-domain information of the angular velocity, and the spectrometer reads and analyzes the frequency-domain information of the angular velocity.

2. The decoupling device of a silicon-based cavity optomechanical system gyroscope based on FSR multi-mode according to claim 1, wherein In the optical resonance characteristic transmission curve, the frequency corresponding to the peak value of the single FSR resonance peak with the highest coupling efficiency in the optical resonance characteristic transmission curve is selected as the frequency of the pump laser, and this resonance peak is defined as the driving peak; the frequency corresponding to the peak value of the single FSR resonance peak with the highest coupling efficiency except the driving peak in the optical resonance characteristic transmission curve is selected as the frequency of the probe laser, and this single resonance peak is defined as the detection peak.

3. The decoupling device of the silicon-based cavity optomechanical system gyroscope based on FSR multi-mode according to claim 1, characterized in that, Both the driving optical fiber and the probe optical fiber are U-shaped optical fibers, and the bottom surfaces of the two U-shaped optical fibers are close to the silicon-based cavity optomechanical microhemispherical gyroscope chip; the included angle between the connecting lines of the centers of the two U-shaped optical fibers and the center of the silicon-based cavity optomechanical microhemispherical gyroscope chip is 45°.

Images