Increasing the data density of free-space optical communications using orbital angular momentum

摘要

Laguerre-Gaussian (LG) light beams possess discrete values of orbital angular momentum (OAM) of lh per photon, where l is the azimuthal index of the mode. In principle l can take on any integer number, resulting in an unlimited amount of information that can be carried by any part of the beam - even a single photon. We have developed a technology demonstrator that uses OAM to encode information onto a light beam for free-space optical communications. In our demonstrator units both the encoding and decoding of the orbital angular momentum states is achieved using diffractive optical components (holograms). We use 9 different OAM values; one value is used for alignment purposes, the others carry data.