Covert Optical Communication over Turbulent Terrestrial Free-Space Optical Link

Unlike traditional secure communication methods, denying unauthorized access to the content of the transmitted message, the covert communication prevents detection of the transmission attempt in the first place. In this invited paper, we review our recent activities on covert free-space optical (FSO) communication activities at the University of Arizona (UA). At UA we have established a 1.5 km long FSO communication link between Optical Sciences Meinel and ECE Department buildings. We use an EDFA as an ASE noise source for covert communication and perform the BPSK signalling over the FSO link at 10 Gb/s data rates. To deal with the atmospheric turbulence effects we use the adaptive optics. We have demonstrated successful covert operation in the strong turbulence regime.