星间光通信发射终端激光耦合单元的设计及实验研究

激光耦合系统是星间光通信系统的重要组成部分。针对星间光通信系统的要求，本文采用一种新型的半导体激光耦合方案，用前后正交的非球面柱面透镜准直半导体激光束，再经渐变折射率（GRIN）自聚焦透镜聚焦耦合入单模光纤。就耦合效率随半导体激光器对光轴的偏离和对光轴角度的偏转进行了研究，发现耦合效率的变化灵敏度不高；同时，在光纤尾纤处测量了输出功率随驱动电流的变化关系，单模运行的半导体激光二极管经耦合后，出纤功率可以达到80mW，满足了星间光通信的要求。

Design and Experimental Research of the Optical Coupling Unit for the Transmitting Terminal of Intersatellite Optical Communication System

The laser diode coupling unit is an important part of the intersatellite optical communication system. In this paper, we proposed a new method of coupling in terms of the request of the intersatellite optical communication system. Using an aspherical cylindrical lens whose front cylindrical lens is orthonormal to its back cylindrical lens collimates the laser beam, and then is focused by a GRIN lens and couples to the single-mode fiber. We studied how the coupling efficiency changes with the fiber position displacement and fiber axial angle variation, and we found that the coupling efficiency is not sensitive to the two parameters. On the other hand, we tested the optical power versus the driver current at the end of the fiber, and obtained 80mW output power at the end of fiber, which shows the optical unit is satisfied the designed request.