Abstract:To improve the transmission quality of four frequency differential laser gyro beam in ring cavity, based on loss difference theory and by combining with mathematical statistics, the effects of the changes of optical axis mismatch angle and optical rotatory angle of quartz crystal on the left and right light field polarization in ring cavity were studied, including the variation laws of difference loss in RMS value, variation range and variance in each collection. The results show that, the optical axis mismatch angle needs to approach 0°, and the optical rotatory angle also need be around 90° in order to achieve ideal polarized light with left and right symmetry and stable laser gyro cavity structure. The limit values of each statistical parameter of the difference loss can provide a quantitative description for the stability of the laser gyro cavity structure.