Non-line-of-sight optical communication based on orbital angular momentum

Optical non-line-of-sight (NLOS) communication can exploit the indirect light path to provide free-space communications around obstacles that occlude the field of view. Here we propose and demonstrate an orbital angular momentum (OAM)-based NLOS communication scheme that can greatly improve its channel dimensionality. To verify the feasibility for extending the amount of multiplexed OAM channel dimensionality, the effects of bit accuracy versus the number of channels in measuring OAM modes are quantified. Moreover, to show the ability for broadcast NLOS tasks, we report a multi-receiver experiment where the transmitted information from scattered light can be robustly decoded by multiple neuron-network-based OAM decoders. Our results present a faithful verification of OAM-based NLOS communication for real-time applications in dynamic NLOS environments, regardless of the limit of wavelength, light intensity, or turbulence. (C) 2021 Optical Society of America