Utilizing Structured Modal Beams in Free-Space Optical Communications for Performance Enhancement

There is a growing interest in utilizing structured beams in free-space optical (FSO) communications. With uniquely tailored spatial amplitude and phase profiles, structured beams can be utilized in different ways to enhance the system performance of FSO links. This article will discuss advances in the utilization of structured beams from three aspects, including (i) transmitting multiple orthogonal structured beams each carrying an independent data channel for capacity enhancement, (ii) shaping the beam at the transmitter by coherently combining multiple modes for pre-compensating link impairments, and (iii) using unique properties of the structured beam to increase link robustness.