Adaptive optics techniques without a wave-front sensor based on guide laser in atmospheric laser communications

Abstract

In order to improve the performance of the intensity modulation with direct detection atmospheric laser communication system, adaptive optics technique without a wave-front sensor based on guide laser is proposed. Performance metric detector replaces the wave-front sensor in the adaptive optics, so that the invalidation of wave-front measurement and compensation in strong scintillation is avoided. The induced guide laser eliminates the misjudgment of attribute the intensity change caused by intensity modulation to the phase distortion. Numerical simulation based on SPGD algorithm shows that when the performance metric of the guide laser is increased from 0.09 to 0.67, the far-field Stehl ratio of carrier wave laser can be increased from 0.0028 to 0.6138, almost 220 times improvement, which indicates the adaptive optics system can reduce the bit-error and improve the performance of atmospheric laser communication greatly.