Sidelobe-modulated optical vortices for free-space communication

Abstract

We propose and experimentally demonstrate a new method for free-space optical (FSO) communication, where the transmitter encodes data into a composite computer-generated hologram and the receiver decodes through a retrieved array of sidelobe-modulated optical vortices (SMOVs). By employing the SMOV generation and detection technique, the usual stringent alignment and phase-matching requirement of the detection of optical vortices is released. In transmitting a gray-scale picture with $180\times 180$ pixels, a bit error rate as low as $3.01\times {10}^{-3}$ has been achieved. Due to the orbital angular momentum multiplexing and spatial paralleling, this FSO communication method possesses the ability to greatly increase the capacity of data transmission.