First Experimental Demonstration of Adaptive Optics Pre-Compensation for GEO Feeder Links in a Relevant Environment

The future of very high throughput optical links between the ground and GEO satellites depends on the ability to overcome turbulence channel disruptions caused by the optical propagation through the atmosphere. Pre-compensation by adaptive optics has been identified as a game changer, as it could theoretically provide for the uplink the additional margin necessary to secure the link budget. Several experimental activities have been reported to investigate the practical increase that can be expected from AO pre-compensation, demonstrating very promising results. Due to the proximity of the line of sight from ground and the strong variability of turbulence conditions these results would benefit from a confirmation on a more representative line of sight. The line of sight between ESA's Optical Ground Station and the top of Mount Teide provides an unprecedented opportunity to provide this confirmation in a relevant environment. We report here the results of the first experimental demonstration of uplink pre-compensation performed on this line of sight in April 2019. The increase of average optical power is demonstrated and compared to expected performance. The influence of anisoplanatism is demonstrated and quantified; consequences on the future of GEO feeder links are inferred.