摘要
在采用同轴反射式光学天线的卫星光通信终端中,发射光束受天线次镜的遮挡,将损失部分能量。为消除次镜遮挡,提高光通信终端的发射效率,提出一种基于衍射光学元件的新方法。该方法利用衍射原理将光束整形为圆环光束,以规避次镜遮挡。按照遮挡比和切断比固定和变化这两类情况进行了仿真设计,前一类仿真结果表明:当遮挡比为15,切断比为1.5时,远场强度峰值提高了40%。后一类情况的仿真结果则表明:遮挡比越大,系统透过率和远场峰值强度越高,远场光束的主瓣宽度和强度峰值相对增量则分别变窄和变低;切断比越大,强度峰值的相对增量也越大。该方法提高了卫星光通信系统发射端的发射效率,同时也改善了接收端的光束质量。
In satellite optical communication transmitter with reflective telescope of two-mirror on axis.a large mount of the transmitted energy will be obscured by the secondary mirror.A novel method based on diffractive optical elements (DOE) is proposed for offsetting it.The beam centrally obscured is reshaped to annulus beam by a diffractive beam shaper and another phase corrector,as a result central obscuration is avoided.Numerical simulation is carried out with fixed obscuraction ratio and truncation ratio,and variation of them,respectively.Subsequent numerical simulation reveals that peak energy of far field is raised about forty percent under the condition of obscuration ratio is 15,and truncation ratio is 1.5.And numerical modelling of the latter are as follows:the larger obscuraction ratio,the larger transmission efficiency of whole system and peak energy of the far field,the narrower the width of main lobe of far field pattern,and the lower relative increment of peak energy;The larger truncation ratio,the larger relative increment of peak energy of beam in far field.This work can improve the emission efficiency of transmitter and energy density of receiver plane in satellite optical communication system.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2009年第3期581-586,共6页
Chinese Journal of Lasers
基金
哈尔滨工业大学优秀团队支持计划
关键词
光通信
发射效率
衍射光学元件
光束整形
optical communication
emission efficiency
diffractive optical elements(DOE)
beam shaping
