盲优化波前校正提高自由空间光通信光纤耦合效率

为了提高自由空间光通信系统的光纤耦合效率，介绍了一种新颖的基于盲优化波前校正的自适应光学系统。该系统不使用波前传感器,而是在信号进入接收端前，将畸变光信号分束后送入光电探测器，进行耦合效率计算；采用耦合效率的估计公式斯特列尔比为目标函数，用随机并行梯度优化算法最大化目标函数，以实时控制变形镜，从而使耦合进入单模光纤的光达到最优。数值结果表明，此系统能使光纤耦合效率从6%提高到约60%。

Improving fiber coupling efficiency of free space optical communication using blind optimization wavefront correction

To improve the fiber-coupling efficiency of free space optical communication systems, an adaptive optics system based on blind optimization is suggested to correct wavefront aberrations caused by atmospheric turbulences. The system adopts no wavefront sensor. The aberrated signal is splitted into a photoelectric detector to calculate the coupling efficiency before it enters the receiver. The stochastic parallel gradient descent algorithm (SPGDA) is then used to adapt the micromachined deformable mirror to optimize the optical power coupled into the fiber, with the Strehl ratio, the estimation formula of coupling efficiency, as the objective function. Numerical results demonstrate that the coupling efficiency is improved from 6% to about 60%.