Adaptive Optics (AO) is rapidly growing to be an essential part of the Free Space Optical Communications (FSOC) field. AO for FSOC poses different challenges to astronomical AO due to the need to operate in worst case turbulence scenarios, at sites of potentially poor seeing conditions, and also the need to track fast moving Low Earth Orbit (LEO) satellites across the sky.

One solution to these challenges is to run a highly optimised Real-Time Control system at very high frequencies ( > 10 kHz), however this may not be necessary. At DLR-KN, we are working in collaboration with the Laboratory Charles Fabry from Institut d’Optique to develop high performance optimal controllers that have the potential to alleviate the need for such high iteration rates by modelling turbulence conditions and predicting its evolution. This model-based control can be especially fruitful in the LEO case, in which the movement of the satellite induces a high-velocity apparent motion of the high-altitude turbulence layers, leading to dominant frozen flow effects.

Here, we report on adaptations to the controllers optimised for astronomical applications to the field of FSOC and present simulation results from an end-to-end optical propagation and AO simulation, demonstrating their effectiveness.

Joana Torres, DLR