A novel space division multiplexing system for free space optical communications

TL;DR

This paper introduces a new space division multiplexing method for free space optical communications using spatial phase encoding, enabling higher capacity through innovative phase mask designs and combining OAM multiplexing with radial phase encoding.

Contribution

The paper presents a novel SDM technique based on spatial phase encoding, expanding beyond traditional methods like OAM multiplexing, with experimental validation of multiplexing and de-multiplexing schemes.

Findings

Successful multiplexing and de-multiplexing of Gaussian beams using phase masks

Demonstrated combination of OAM multiplexing with radial phase encoding to increase capacity

Proposed phase encoding schemes effectively enhance free space optical communication channels

Abstract

We propose a novel space division multiplexing (SDM) technique based on spatial phase encoding, which may provide a new perspective beyond the conventional SDM in free space optical communications, such as multiplexing of orbital angular momentum (OAM). In our scheme, Gaussian beams are multiplexed with a set of spatial phase masks, and then transmitted in the Fourier domain via spherical lens. And another phase masks with matched patterns sandwiched by two lenses are used to de-multiplex the corresponding channels. Three different phase masks, namely, planar linear encoding, radial linear encoding and hybrid of radial and azimuthal linear encoding, are proposed and analyzed. The multiplexing and de-multiplexing of Gaussian beams are successfully implemented using these phase encoding approaches. We prove that the OAM multiplexing and radial phase encoding can be combined to further increase the communications capacity in free space