Three closed loop noise suppression method for resonant micro optical gyroscope

Abstract

For resonant micro-optical gyroscope (R-MOG), backscattering noise and optical Kerr noise are the main noises that affect the output accuracy of the gyroscope, and it is difficult to suppress them completely. This paper introduces a method to suppress the optical Kerr noise generated by the front end by compensating the optical power difference while suppressing the backscattered noise. Based on a single light source, the system changes the frequency difference between clockwise and counterclockwise optical paths through double-phase modulation, so as to improve the carrier rejection ratio and suppress the backscattered noise. At the same time, a high-speed feedback loop based on intensity modulator is designed, which is added to the optical loop to enhance the optical power, so as to reduce the impact of optical Kerr noise. The experimental results show that this method effectively suppresses the backscattered noise and optical Kerr noise, improves the output accuracy of the gyro by two orders of magnitude, and finally observes the long-term bias stability of 0.982°/h.