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

Abstract

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.

Single-Mode Fiber Coupling with Adaptive Optics for Free-Space Optical Communication under Strong Scintillation

“…to strengthen the fluctuations amplitude). These results are consistent with the analysis performed on the uplink pre-compensated fiber coupling presented in [13]. This work will be complemented by analytical modeling of SMF coupling in the encountered turbulence conditions, and by further processing of the large variety of data acquired during this project.…”

Performance analysis of an adaptive optics based optical feeder link ground station

“…To consolidate these results, a more realistic AO correction will be simulated. Nevertheless, considering state of the art components and already demonstrated performance in a relevant environment [8], expected results shall not significantly deviate from those presented here. Building on these results ONERA is currently designing an AO system dedicated to uplink pre-compensation for GEO feeder links.…”

“…This phenomenon, called point ahead anisoplanatism, and its consequences on the first moments of uplink ROP have been extensively documented [3][5] [6]. The feasibility of uplink precompensation by adaptive optics in a relevant environment has also already been demonstrated [8]. Key challenges remaining to be addressed prior to an on sky demonstration of an uplink high data rate with respect to the ground segment are to:…”

The H2020 VERTIGO project towards tbit/s optical feeder links

“…Besides, during the demonstration, the turbulence conditions will be monitored thanks to adaptive optics data (wavefront sensor measurements, and control commands) so as to facilitate the performance analysis [6].…”