空间激光到单模光纤（SMF）耦合技术是自由空间激光通信中的关键技术之一。在Matlab环境下仿真分析了单项波前像差和大气湍流像差对空间光到SMF耦合效率的影响，研究了随机并行梯度下降（SPGD）算法校正大气湍流中整体倾斜像差的迭代过程及对耦合效率的影响。仿真结果表明，SMF耦合效率随单项波前像差均方根（RMS）增加而降低，校正大气湍流中整体倾斜像差后，SMF耦合效率都有提高；当D/r0较小时，大气湍流像差中影响SMF耦合效率的主要像差为倾斜像差。搭建了基于SPGD算法的闭环控制系统，利用自适应光纤耦合器（AFC）校正模拟湍流倾斜像差后，SMF平均耦合效率从30.07%提升到了61.72%；耦合效率的均方误差（MSE）从7.28%降低到2.16%。

Coupling laser beam with plane wavefront into single-mode fiber (SMF) is a key technology in free-space optical communication. The influences between single-order wavefront aberration and atmospheric turbulences aberration on SMF coupling efficiency are analyzed in the Matlab simulation environment, respectively. The iteration courses of tilts correction using stochastic parallel gradient descent (SPGD) algorithm and their effects on coupling efficiency are studied. The simulation results show that SMF coupling efficiency drops with the increment of root-mean-square (RMS) value of single-order wavefront aberration, while the SMF coupling efficiency improves when the tilt aberrations of atmosphere are compensated. And the tilts are the main acting factor to SMF coupling efficiency when D/r0 is small. A closed-loop control system based on SPGD algorithm is established, where the adaptive fiber coupler (AFC) is employed to correct tilt aberrations of simulated turbulence. After tilt aberrations of simulated turbulence are corrected, the SMF coupling efficiency increases from 30.07% to 61.72% and the mean-squared-error (MSE) drops from 7.28% to 2.16%.