临近空间相干激光通信链路是天地一体化高速通信网络节点间连接的重要链路。围绕外差效率这一表征大气湍流扰动后信号光和本振光相干合成的指标,推导了非均匀湍流路径上的外差效率理论表达式,并结合大气折射率结构常数廓线,开展了临近空间-地面、临近空间-临近空间和临近空间-低轨卫星三类临近空间相干激光通信链路的外差效率仿真。仿真结果表明: 临近空间-低轨卫星链路可以忽略大气对外差效率的影响; 如果临近空间-临近空间链路距离大于500 km或是临近空间-地面链路天顶角大于60°,外差效率将小于50%,有必要采用自适应光学技术进行补偿。

Coherent laser communication links of near space are important links of the integrated sky-earth high speed communication networks. This research focused on the heterodyne efficiency which represents coherent index of local laser and signal laser influenced by the atmospheric turbulence. The theoretical heterodyne efficiency expression with the path influenced by non-homogeneous turbulence was derived. The simulations of heterodyne efficiency of near space-earth, near space-near space and near space-low orbit satellite coherent laser communications links were given. The simulation results show that the atmospheric turbulence effect of near space-low orbit satellite links can be neglected. If the link distance between near space-near space is greater than 500 km or the zenith angle of near space to ground link is greater than 600 degrees, the heterodyne efficiency will be less than 50% and it is necessary to compensate the effect of atmospheric turbulence by using of adaptive optics.