非共面腔激光陀螺复杂象散研究及其光阑设计

Study on the Complex Astigmatism in Nonplanar Cavity RLG and Design of the Diaphragm

基于包括子午和弧矢方向完整的4×4旁轴光线传输矩阵,建立了非共面谐振腔激光陀螺整体环绕传输矩阵.根据该矩阵,计算q参量矩阵,代入实际参量,分析并仿真计算了某型非共面谐振腔环形激光陀螺的复杂象散,得到了光路上任意位置光斑尺寸.实验采用CCD测量了该型激光陀螺输出光不同位置的光斑尺寸,通过多点测量值双曲线拟合的方法得出束腰宽度,仿真计算和实验结果一致.采用高斯光束理论,根据光场分布、光阑尺寸和位置确定衍射损耗,设计出合适的光阑方案,即将光阑设置在束腰位置,其形状为圆形,尺寸与束腰比值为2左右.实验证明该方案保证了该型非共面谐振腔环形激光陀螺单横模工作.

Based on 4×4 matrix including meridian and latitude,the round-trip matrix of nonplanar cavity was established.According to the matrix,the q parameters matrix was calculated,the complex astigmatism in some nonplanar cavity ring laser gyro（RLG） was analyzed,and the spot radius of Gaussian beam at any location was obtained theoretically.Then the spot radii of the out-cavity Gaussian beam were measured by CCD,and the Gaussian beam waist was obtained by hyperbola fitting.The result was consistent with the theoretical one.According to spot radii,diaphragm radii and location,the diffraction loss was obtained.The designed diaphragm located at the Gaussian beam waist is circular,and the ratio of diaphragm radius to waist radius is about 2.The designed scheme guarantees the nonplanar cavity RLG works with single TEM00 mode.