  Free space communications (FSO) is interesting for distant applications where
high bandwidth is needed while using a fiber is not possible. However these
links have to face several issues, and the most important one is the beam
scintillation due to the propagation through a turbulent media, the atmosphere.
Several mitigation strategies have been developed, but the best way to suppress
scintillation is to use adaptive optics, widely used now in astronomy. The main
difficulty for FSO is to probe the wavefront fast enough to have a good
turbulence correction. This was not possible due to the lack of wavefront
sensors working in the SWIR. C-RED 3 is a 640x512 SWIR camera running at 600FPS
full frame and has the legacy of all the developments of astronomical infrared
fast wavefront sensors on top of specific features for FSO (Low SWaP, Low
Cost). We will present the performances of this new camera and demonstrate how
it fulfills the needs of FSO adaptive optics.
