光学整流罩对机载激光通信光束远场发散角的影响

Influence of Optical Dome on Airborne Laser Communication Beam Far-Field Divergence Angle

分析了同心球面光学整流罩内、外表面的球心与机载激光通信发射天线的万向节点不重合时,非对称的光学整流罩对通信光束远场发散角的影响。结果表明,在最大通信光束远场发射角约为54°的条件下,外部口径为200mm、厚度为5 mm的K9球冠整流罩使口径为30 mm的通信光束远场发散角由126μrad扩展到5.27-6.46mrad,而仅由整流罩面形加工精度引起的通信光束远场发散角变化相比由整流罩光焦度引起的通信光束远场发散角变化十分微小,可以忽略不计。利用球面透镜补偿通信光束远场发散角的变化,可使通信光束在整个发射角范围内的远场发散角均小于600μrad。

When the centers of inner and outer surfaces of the concentric spherical surface dome and the gimbal joint of the airborne laser communication transmitting antenna are not coincidence, the influence of the asymmetry optical dome on communication beam far-field divergence angle is analyzed. The results show that, at a maximal communication beam far-field divergence angle of 54°, a K9 spherical dome with the external diameter of 200 mm and the thickness of 5 mm makes the communication beam far-field divergence angle expand to 5.27-6.46 mrad from 126μrad. The communication beam far-field divergence angle variation purely introduced by the dome surface manufacturing precision is very tiny, and can be ignored compared with the variation introduced by the dome optical power. A lens with spherical surfaces is used to compensate the communication beam far-field divergence angle change, and the communication beam far-field divergence angle of the whole transmitting angle range is smaller than 600 grad.