程长控制镜是保持环形谐振腔腔长稳定的重要器件之一, 温度变化引起的热形变直接影响环形谐振腔的光路形状和光束质量。首先利用ANSYS软件建立了程长控制镜的有限元仿真模型, 分析了不同温度条件下程长控制镜的温度场及耦合场, 得到了程长控制镜反射镜面中心形变量云图, 对变温条件下程长控制镜反射镜面中心形变规律进行了研究, 得到了反射镜面中心形变量与温度的关系函数。然后, 通过扫模实验和温度实验验证了有限元模型的正确性, 计算相对误差为2.5%。最后, 仿真分析了程长控制镜各个部件导热系数、杨氏模量、线膨胀系数的影响规律。不同材料参数下, 导热系数以及密度对形变量影响较小, 杨氏模量和线膨胀系数对形变量影响较大, 形变量与杨氏模量成反比, 与线膨胀系数成正比。本文首次研究了常温、高低温及变温条件下程长控制镜的温度场和耦合场, 并对材料参数的影响规律进行了定量分析, 研究结果对程长控制镜的材料选择与优化设计有一定指导意义。

Path length control mirrors (PLCM) are important devices used to keep the cavity length of ring resonators stable. The deformation caused by the temperature variation directly affects the optical path shape and beam quality of ring resonators. In this paper, a finite element simulation model of PLCMs was established using ANSYS. Subsequently, the model was used to analyze the temperature and coupled fields of a PLCM under different temperature conditions. The deformation distribution in the middle of the mirror was obtained. Next, the accuracy of the finite element model was verified by sweep and temperature experiments, with an error of less than 2.5%. Finally, the deformation in the middle of the mirror under the variable temperature conditions was studied, obtaining the relationship between the deformation and the temperature. The influence of the thermal conductivity, Young 's modulus, and linear expansion coefficient of each component of the PLCM were simulated and analyzed. For different material parameters, the thermal conductivity and density have little effect on the deformation, while the Young's modulus and linear expansion coefficient greatly influence the deformation. The deformation was found to be inversely proportional to the Young's modulus and proportional to the linear expansion coefficient. In this paper, the temperature and the coupled fields of the PLCM under normal, high-low, and variable temperature were studied for the first time. In addition, the influence of the material parameters was quantitatively analyzed. The results of this paper have a guiding significance for material selection and optimization of PLCMs.