An Optical Vortex refers to a type of structured light field characterized by a phase singularity at its center. This singularity results in a dark core surrounded by a spiraling wavefront. The phase of the electromagnetic wave in an optical vortex twists around the singularity axis, creating a helical or vortex-like structure in the wavefront.


Coherent optical wireless communication link employing orbital angular momentum multiplexing in a ballistic and diffusive scattering medium

We experimentally investigate the scattering effect on an 80 Gbit/s orbital angular momentum (OAM) multiplexed optical wireless communication link. The power loss, mode purity, cross talk, and bit error rate performance are measured and analyzed for different OAM modes under scattering levels from ballistic to diffusive regions. Results show that (i) power loss is the main impairment in the ballistic scattering, while the mode purities of different OAM modes are not significantly affected; (ii) in the diffusive scattering, however, the performance of an OAM-multiplexed link further suffers from the increased cross talk between the different OAM modes.