System and method for communication using orbital angular momentum with multiple layer overlay modulation

Abstract

A communications system includes a transmitter for transmitting an optical signal including a plurality of data streams over an optical communications link. The transmitter includes first signal processing circuitry for processing each of the plurality of input data streams to generate a parallel pair of data streams including an in-phase stream (I) and a quadrature-phase stream (Q) for each of the plurality of input data streams. The first signal processing circuitry modulates a first and second parallel pair of data streams with a selected one of at least three mutually orthogonal functions at a first and second signal widths, respectively, to generate a plurality of first data sub-layers and a plurality of second data sub-layers and generates a plurality of composite data stream by overlaying the first data subs-layers with the second data sub-layers at a preconfigured overlay offset. Second signal processing circuitry places the plurality of composite data streams on a wavelength of the optical communications link. Each of the plurality of composite data streams having a different orbital angular momentum associated therewith to enable transmission of each of the plurality of composite data streams on the wavelength at a same time.