McDonald, DouglasDouglasMcDonaldBellossi, RaphaëlRaphaëlBellossiGladysz, SzymonSzymonGladyszLambert, AndrewAndrewLambert2022-03-152022-03-152021https://publica.fraunhofer.de/handle/publica/41249710.1117/12.2600085Coherent free-space optical (FSO) communications systems offer both an opportunity for significantly increased data rates and improved security compared to conventional radio frequency (RF) systems. A key challenge in implementing FSO systems is the characterization and mitigation of atmospheric turbulence present along the optical channel. In this work, we present experiments demonstrating coherent free-space optical communications over a two-pass 800 m link with data rates on the order of gigabits per second (Gbit/s). The link consists of a single telescope and retroreflector. At the start/end point of the monostatic link we have built an optical transceiver capable of coherent communications. We present here design considerations and results from transmission in moderate turbulence.enfree space optical communicationscoherent optical communicationsatmospheric turbulene004670conference paper