Design and Testing of Adaptive Optics Systems for Free Space Optical Communication

Adaptive Optics (AO) represents one of the main turbulence mitigation techniques for a feasable implementation of Free Space Optical Communcation (FSOC) networks. The aim of my work is to give to system engineers the proper tools for the design and dimensioning of AO systems for FSOC applications. In the context of the European Space Agency (ESA)'s HydRON SIMULation testbED (HySIMULED) project, I developed an analytical model and a Monte-Carlo numerical model for evaluating the improvement given by using AO in all the relevant GEO and LEO feeder link scenarios, in a way such that the results can be easily integrated in standard FSOC link budgets. In particular, both downlink and uplink are covered and, for the uplink, both pre-compensation based on the downlink signal and on Laser Guide Star (LGS) is modelled. With the aim of comparing the two models, simulations in relevant GEO and LEO link configurations and turbulence scenarios have been performed. Thus, the results have been evaluated in terms of coupling losses for the downlink and in terms of scintillation, beam spread and beam wander losses for the uplink. Finally, these models have been used for the design and dimensioning of the AO systems of two ESA projects, i.e. the Generic Adaptive Optics Module (GAOM) project and the HydRON DEMOnstrator (HyDEMO) project. For the GAOM project the preliminary experimental results of the AO system performance are reported, comparing them with what was expected from the simulations.