高热稳定性测风Fabry-Perot干涉仪标准具的设计

Design of thermal stable Fabry-Perot etalon for wind measurement

针对星载测风Fabry-Perot(F-P)干涉仪的核心部件F-P标准具的热稳定性对测风精度的影响,从标准具结构设计角度(材料、形状和固定方式)分析了标准具的热稳定性,并给出最优设计方案。通过对光学元件结构尺寸的优化设计,得出了F-P标准具光学元件的最佳形状尺寸,即平板厚度为25mm,间隔元件的角度为40°。采用柔性结构固定方式,计算了F-P标准具机械结构的形状尺寸。最后基于有限元法,分析了光学组件和整个标准具的热变形。分析结果显示,当环境温度变化0.1℃时,光学组件平板中心间隔变化量为0.64nm,整个标准具平板中心间隔变化量为0.28nm,通光口径边缘处间隔变化量为0.2nm,相对于波长λ为630nm的气辉光谱线约为λ/2 250和λ/3 150,并且平板间隔变化量沿着径向向外逐渐减小。得到的结果显示,优化设计后的结构参数满足风速为5m/s时测量精度对热稳定性的要求,同时满足力学性能要求。

In consideration of the effect of thermal stability of a Fabry-Perot（F-P） etalon in the satellite-borne F-P interferometer on wind measurement,this paper analyzes the thermal stability of the F-P etalon from its construction design including materials,shapes and fixed forms,then,it optimizes the design.With optimization design,the optical elements in the etalon are constructed,which shows that the two plates are all 25 mm thick,and the spacers are all 40° in angles.Then,the dimensions of mechanical structure of the etalon are calculated using flexible structure.Finally,the thermal distortions of optical elements and the etalon are discussed.It shows that the gap dimension changes in the centers of the optical elements and the etalon are 0.64 nm and 0.28 nm and the gap dimension change of the etalon is 0.2 nm when the temperature changes 0.1 ℃.Furthermore,the airglow spectral lines are ~λ/2 250 and ~λ/3 150 at 630 nm respectively,and the gap dimension changes of the etalon fall along the radius from the center to the verge.These results demonstrate that optimized structure parameters meet the requirements of measuring accuracy for thermal stability and mechanical stability at a wind velocity of 5 m/s.