Crosstalk characteristics of orbital angular momentum of focused perfect vortex beam in atmospheric turbulence

Abstract

Abstract The perfect optical vortex beam (POV) is a special kind of vortex beam, whose radius is independent of its orbital angular momentum (OAM) mode, but the atmospheric turbulence (AT) causes crosstalk between different topological charges, which is a serious challenge in OAM-based communication system. We establish a theoretical model with a turbulence suppression effect for deriving the spiral spectrum of a focused perfect optical vortex beam (FPOV) after propagation through anisotropic AT. Through numerical analysis, we simulate the behavior of FPOV under different turbulence and beam parameters to better understand the effect of the received probability and its corresponding modal crosstalk under various conditions. In addition, the simulation of AT uses the multi-phase screen method to verify the theoretical results. The results show that the changes in topological charge, wavelength, receiving aperture, beam waist, and hollow radius all have an influence on the received probability. Also, some strategies for selecting turbulence parameters to reduce modal crosstalk in anisotropic AT are also discussed. The focus would reduce the effect of turbulent aberrations on the signal OAM mode received probability, and the FPOV provided better performance than the POV, which may be useful in OAM-based free space optical communication.