Adaptive optics pre-compensation for GEO feeder links: Towards an experimental demonstration

High throughput ground to GEO satellite telecommunication systems will require very capacitive links for the uplink. When diffraction limited, a few optical Watts per channel are sufficient to close the link budget. In the presence of atmospheric turbulence, higher emission powers are necessary to cope with the subsequent disruptions of the beam. Pre-compensation by adaptive optics has been identified as a key strategy to keep the requested power at reasonable levels. However its performance is limited by point-ahead anisoplanatism. Fine trade-offs shall be carried out to overcome this limitation while considering the specificities of optical telecommunication requirements (low fading probably, short fading duration, manageable cost and complexity). The expected performance of the pre-compensation by adaptive optics for optical feeder links is investigated through numerical simulations. A ground-to-ground experimental demonstration is proposed. The selected slant line of sight and the beam geometry is shown to induce turbulence effects, including angular decorrelation, that are representative of the GEO feeder link scenario when considering an appropriate setup.