为满足星间激光通信对高隔离水平光学天线的要求，实现对光学天线隔离度的仿真分析和优化，提出了一种将红外系统冷反射的特征控制量YNI值作为衡量光学元件表面后向反射能量强度，并控制光学天线优化以提高隔离度水平的方法。在LightTools软件中为某激光通信终端的卡塞格林天线创建了实体模型，通过仿真分析得出了各元件表面的后向反射率。在ZEMAX软件中以增大各元件表面的YNI值为目标优化天线结构。对比优化前后的结果，系统的后向反射率从3.068 8×10－4减小到1.075 5×10－5，隔离度从-35.13 dB减小到-49.68 dB。优化后的卡塞格林天线具备较高的隔离度水平，可用于星间激光通信。

To meet the requirement of inter-satellites laser communication for higher isolation level of optical antenna and achieve the simulation analysis and optimization of optical antenna′s isolation level, a method using the YNI value (characteristic value of narcissus in infrared optical system) as the evaluation of back-reflection energy intensity of optical element surfaces and increasing the isolation level of optical antenna by controlling its optimization is presented. An entity model of Cassegrain antenna in an inter-satellites laser communication terminal is established by LightTools software, and back-reflection ratio of each element surface is obtained through simulation and analysis. Optical antenna′s structure is optimized by increasing the YNI value of each element surface by ZEMAX software. Comparing the results before and after optimization, the optical antenna′s back-reflection ratio decreases from 3.068 8×10－4 to 1.075 5×10－5 and the isolation level decreases from -35.13 dB to -49.68 dB. The optimized Cassegrain antenna has a high isolation level, which can be used for inter-satellites laser communication.