Reliability of detecting optical vortex with a Shack-Hartmann wavefront sensor in a scintillated vortex beam

An optical vortex, which possesses positive or negative topological charge, can be used as an information carrier in a free-space optical communication system because its special properties. By detecting the vortex with a Shack- Hartmann wavefront sensor, one can extract the information transferred by a vortex beam. However, additional optical vortices can spontaneously appear in the beam propagating over a long distance in the atmosphere or through a strongly turbulent medium. As a result, the vortex beam will contain a significant number of new vortices besides the initial one in the system receiving aperture. This may destroy the information carried by the initial vortex. In the paper, we will describe the reliability of detecting vortex with a Shack-Hartmann wavefront sensor in a scintillated vortex beam. The initial vortex can be detected even if the beam is strongly scintillated and with numerous newly emerged vortices. Numerical simulations and statistics show that the information can still be accurately interpreted to a certain extent from a vortex beam propagating through weak-to-strong atmospheric turbulence.