Multiplexing free-space channels using twisted light

Free-space optical communications using orbital-angular-momentum multiplexing combined with MIMO-based spatial multiplexing.

We explore the potential of combining the advantages of multiple-input multiple-output (MIMO)-based spatial multiplexing with those of orbital angular momentum (OAM) multiplexing to increase the capacity of free-space optical (FSO) communications. We experimentally demonstrate an 80 Gbit/s FSO system with a 2×2 aperture architecture, in which each transmitter aperture contains two multiplexed d...

Space-Path Division Multiplexing Technique over Frequency Selective MIMO Channels

This paper proposes a new multiple-input multiple-output (MIMO) eigenmode transmission technique in frequency selective multipath channels. The proposed scheme exploits the two-dimensioned (spatial and path domain) signal separability in frequemcy selective MIMO channels, for which different data streams are transmitted on each path component’s eigenmodes. A soft interference canceling minimum ...

Light Modes of Free Space

Terabit free-space data transmission employing orbital angular momentum multiplexing

The recognition in the 1990s that light beams with a helical phase front have orbital angular momentum has benefited applications ranging from optical manipulation to quantum information processing. Recently, attention has been directed towards the opportunities for harnessing such beams in communications. Here, we demonstrate that four light beams with different values of orbital angular momen...

Free-space quantum key distribution by rotation-invariant twisted photons.

"Twisted photons" are photons carrying a well-defined nonzero value of orbital angular momentum (OAM). The associated optical wave exhibits a helical shape of the wavefront (hence the name) and an optical vortex at the beam axis. The OAM of light is attracting a growing interest for its potential in photonic applications ranging from particle manipulation, microscopy, and nanotechnologies to fu...