Mitigation of Atmospheric Effects by Adaptive Optics for Free-Space Optical Communications

Data-rates of long-range free-space optical communication links are deteriorated by atmospheric turbulence which causes power in the bucket fluctuations. In order to compensate for those effects the use of adaptive optics is envisioned. Different solutions have been proposed for the correction. We study here the performances of several compensation methods, encompassing both amplitude and phase and phase-only precompensation. In the case of phase-only precompensation we studied two system designs, one which is dedicated to symmetrical communication systems and the other to dissymmetric systems. In the dissymmetric case we studied two ways of driving the deformable mirror : the use of a Shack-Hartmann wavefront sensor and a model-free phase modulation. For each compensation architecture simulation results covered weak, moderate and strong turbulence conditions.