Hybrid validation of an adaptive optics system for geo downlink

In the realm of Free-Space Optical (FSO) communication systems, the transmission of data via satellite in Geostationary Earth Orbit (GEO) presents unique challenges, particularly in mitigating atmospheric turbulence-induced distortions. We here present the validation of a woofer-tweeter adaptive optics system tailored for a GEO downlink application with sub-microradian pointing requirements in strong turbulent environments. The validation process employs a hybrid approach utilizing results obtained from the experimental setup and its numerical twin in ACEsim (ALPAO Core Engine Simulator). During closed-loop operation, this data is applied to (1) the WFS images to mimic scintillation and (2) to the corrector commands to mimic the atmospheric input phase. This laboratory validation serves as a crucial step towards demonstrating the feasibility and efficacy of adaptive optics technology in GEO downlink applications. The AO system was tested on-sky at the French Optical Ground Station in France in 2024. Latest performance results will be reported.