Research on Polarization Error and Suppression Methods for Integrated Fiber Optic Gyroscopes

The integrated interferometric fiber optic gyroscope has gradually replaced traditional fiber optic gyroscope due to its advantages of miniaturization and low power consumption. However, a significant polarization error arises in integrated optical chips due to no polarization-maintaining fiber connections among individual devices, which considerably reduces the angular velocity measurement accuracy and environmental stability of the gyroscope. Therefore, the paper analyzes the transmission characteristics of optical chips and reveals that the primary factors affecting the polarization error are the extinction ratio of the integrated light source chip and the polarization degree of the waveguide coupler. Simultaneously, we designed a novel waveguide coupler structure to maintain high polarization. Ultimately, we constructed an optical experimental verification platform and manufactured a fiber-integrated chip based on theoretical analysis. Through optical spectrum analyzer and a polarization analyzer, we confirmed that the novel optical chip maintains high polarization extinction ratios. The angular velocity test was conducted in gyro system, and the bias stability under 100s smooth was 0.0496 °/h.