Performance of a coherent free-space optical communications link with wavefront sensorless adaptive optics

Coherent free-space optical (FSO) communications systems present an opportunity for significantly increased data rates in wireless communications. To implement coherent FSO systems, degradation of received signals due to atmospheric propagation must be mitigated. This can be achieved by deploying adaptive optics (AO) systems at the optical receiver to reconstruct wavefronts deformed during propagation. In this work, we present the design and implementation of a coherent FSO communications system which utilizes a wavefront sensorless AO system to improve received signal quality. The performance of the communications system is quantified with and without the use of AO by measuring bit error ratio (BER) and error vector magnitude (EVM).