Investigation of free space optical communications with binary ghost imaging

This paper proposes a free space optical (FSO) communications system based on ghost imaging, and the signal transmission through a 1 km horizontal turbulent channel is numerically investigated. The information is mod-ulated and encoded into a sequence of binary numbers by ghost imaging with object light quantization, and these binary signals are transmitted to a receiver with vortex beams. The communications performance depends on the repeating times of the ghost imaging, and the bit error rate is zero as the repeating times increase to 3000. The secu-rity of the communications system is analyzed, and it is found that the information cannot be correctly decoded without a transformation matrix and secret key. It is confirmed that larger repeating times in the ghost imaging can contribute to the security enhancement and better communications performance. Our results provide a secure scheme for a FSO communications system in the presence of atmospheric turbulence, which has potential for applications in future communications.(c) 2023 Optica Publishing Group