为减轻卫星载荷质量和应对各种突发状况，将成像光学系统同时用作激光发射天线的共口径设计具有重要意义。因此根据特定的成像光学系统给出了共口径设计方法，针对其中基于EDFA功放技术的发射单元与成像系统相匹配的耦合镜头进行了分析与设计，基于此研究了发射高斯光束在该共口径系统中的传输及出射光束的场分布，讨论并仿真分析了耦合镜头与成像主次镜距离的改变对出射光束性能的影响。结果表明，共口径设计满足激光发射要求，并且微调耦合镜头与成像主次镜的距离可以改变出射光束的束腰和远场光强峰值能量从而满足不同的通信需求，且对出射光束的总能量没有明显影响。

To alleviate the load of the satellite and to deal with sudden trouble, research of co-aperture designing methods with which the space imaging optical system can be used as laser transmitting antenna was important. First, the co-aperture design method was proposed based on a given imaging optical system, and the optical coupling elements for meeting the imaging system to the laser transmitting request was analyzed when the laser transmitting system was based on EDFA. Then, the Gauss beam transmitting though the co-aperture system was analyzed, and the field distribution was given. Finally, the effect of distance changing between the coupling elements and imaging system on the transmitted laser were simulated. Result show that the co-aperture design can satisfy the imaging and laser transmitting request, and slightly adjusting the distance between the coupling elements and imaging system can change the transmitted waist and far-field peak energy without bad effect on the total transmitting energy, which make it possible for the system to satisfy different communicating mission.