(Invited) Upgrade of ESA optical ground station with adaptive optics for high data rate satellite-to-ground links

Over the past years, we have successfully applied adaptive optics (AO) in optical ground stations to improve the quality of satellite-to-ground laser communication links. In this paper, we present a design overview of the adaptive optics add-on to the ESA optical ground station (1 m telescope), including optics, components, and the reconstruction scheme. The system is suited to be operated with laser communication systems at 1064 nm or with one in the 1550 nm region. The wave-front sensor is a Shack-Hartmann-sensor (21 sub-apertures across the pupil), matched to a 24×24 actuator deformable mirror. The system is able to remove a large part of the turbulence-induced and static wave-front errors by using more than 90 degrees of freedom (“modes”). Due to a special high-speed infrared camera, the AO control loop is optimized for an update rate of 4 kHz in excess.