Technical research of adaptive fiber coupler array based on SPGD algorithm

Adaptive fiber coupler(AFC) is a new kind of fiber-based adaptive-optics device which can achieve high and steady efficiency in coupling laser beam from space into fibers. Analysis on the feasibility of adopting AFC array as receiver in free space laser communications was studied. Simulation research on the closed-loop control process of AFC array with different number of sub-units using SPGD algorithm under different turbulence conditions was achieved. Simulation results show that: (1) adopting AFC array as receiver can realize high and stable coupling efficiency and alleviate the effects of atmospheric turbulences; (2) coupling efficiency and the algorithm convergence rate promote as the number of the array increases, where the equivalent aperture of the receiver is certain.