Toward the uplink correction: Application of adaptive optics techniques on free-space optical communications through the atmosphere

The optical ground station (OGS), installed in the Teide Observatory since 1995, was built as part of ESA efforts in the research field of satellite optical communications to test laser telecommunication terminals on board of satellites in Low Earth Orbit and Geostationary Orbit. As far as one side of the link is settled on the Earth, the laser beam (either on the uplink or on the downlink) has to bear with the atmospheric turbulence. Within the framework of designing an adaptive optics system to improve the performance of the free-space optical communications at the OGS, turbulence conditions regarding uplink and downlink have been simulated within the object-oriented matlab adaptive optics toolbox as well as the possible utilization of a laser guide star to measure the wavefront in this context to cope with the angular difference in uplink and downlink beams due to the point-ahead angle required for the uplink. Simulations have been carried out by reducing available atmospheric profiles regarding both night-time and day-time measurements and by having into account possible seasonal changes. An AO proposal to reduce atmospheric aberrations and, therefore, ameliorate FSO links performance is presented and analyzed in this paper.