四频差动激光陀螺法拉第片最佳入射角的研究

Optimum incident angle to Faraday wedge of multi-oscillator ring laser gyroscope

为了探究入射光偏振态对四频差动激光陀螺法拉第片最佳入射角的影响,建立四频差动激光陀螺法拉第片三光束干涉的琼斯矩阵,利用计算机进行数值计算,模拟圆偏振光和椭圆偏振光在陀螺仪内的传播方程,并通过搜索不同入射角情况下-40℃~80℃温度范围内磁圆二向色性差分损耗的振幅最小值来选取最佳入射角。结果表明,圆偏振模式下和椭圆偏振模式下法拉第片的最佳入射角有一定差别,这种差别足以影响到激光陀螺仪的测量精度,因此在安装法拉第片时应考虑入射光偏振态对其最佳入射角的影响;此外,法拉第片的最佳入射角与入射光s分量（垂直于入射面）、p分量（平行于入射面）在反射镜上的反射相位差以及反射镜的反射系数均有关。

In order to explore effect of incident light polarization on optimum incident angle to Faraday wedge of multi- oscillator ring laser gyroscope, the Jones matrix for Faraday wedge was established. The circularly polarization and the elliptically polarization were numerically simulated by using MATLAB. The optimum incident angle was obtained by searching for the minimum amplitude of magnetic circular dichroic loss at different incident angles and different temperatures in the range of -40~C ~80~C. The results show the optimum incident angles to Faraday wedge for circularly polarization and elliptically polarization are different. This difference is enough to affect measurement accuracy of multi-oscillator ring laser gyroscope. The impact of incident polarization on the optimum incident angle should be taken into consideration when placing Faraday wedge. Phase shifts of p （perpendicular to incident plane） and s （parallel with incident plane） polarizations, reflecting coefficients of four reflecting mirrors of multi-oscillator ring laser gyroscope have the influence on the optimum incident angle.