卫星光通信天线系统轴向间隔的精确调试方法研究

在卫星光通信系统中，光学天线是影响激光信号发射和接收的关键子系统，干涉仪则是实现其精确装调的有效工具。由于实际使用的干涉仪的波长与光学天线的工作波长通常并不相等，此时利用干涉仪只能完成垂轴像差的调整，而不能完成轴向间隔的精确调试。为实现单波长干涉仪对不同波长光学天线轴向间隔的高精度装调，必须考虑由干涉仪和光学天线的波长差异引入的间隔偏差。根据光学天线在干涉测量装置中的光程差表达式，建立了由波长引起的光学天线物镜和目镜的轴向间隔偏差与干涉条纹变化量的关系式，并据此提出了精确调试光学天线轴向间隔的方法。模拟仿真结果表明，利用该关系式能较精确的完成光学天线轴向间隔的调试，其模拟调试误差小于15%，基本满足卫星光通信终端对光学天线的装调要求。

Research on Precision Adjustment of Axial Spacing of Antenna in Satellite Optical Communication Terminal

Optical antenna consisting of objective lens and eyepiece lens plays a very important role in satellite optical communication terminal whether emitter or receiver, and its assembly accuracy were normally assured by interferometer. However, the focus of objective and eyepiece under testing will constantly change corresponding to its design parameter because the operating wavelength of interferometer differs from that of optical antenna. As a result, only the adjustments of lateral optical aberration were accomplished by using interferometer, but the axial spacing between objective and eyepiece was not still determined quantificationally. In order to determine axial spacing of various optical antennas with different wavelengths by utilizing the same interferometer, the relation between wavelength and axial spacing must be studied. In this paper, a relationship between axial spacing derivation of optical antenna and corresponding alterative number of interference fringes was deduced based on optical path difference, hence axial spacing of optical antenna would be adjusted accurately according to this formula. Emulation results proofs validation of formula, and it also shows that corresponding assembly accuracy can meet requirements of satellite optical communication terminal completely.