Defining the constraints of an adaptive optics system applied to free-space optical satellite and aircraft data downlinks

Abstract

Adaptive Optics (AO) applied to free-space optical (FSO) communications aims to maximize either the power coupled into a single-mode fiber (SMF) or the heterodyne efficiency in coherent-based communications. LEO satellites and aircraft downlinks have to deal with low elevation angles because of the link geometry and short contact time. Due to strong scintillation and phase singularities, below 20°, traditional Shack-Hartmann sensors perform poorly. GEO satellite downlinks have to deal with very low received power levels. Here, we briefly explain the challenges to be addressed by an AO system for communication purposes.