Average capacity of an absorbent and anisotropic turbulent ocean wireless communication link with the nonuniformly correlated Hypergeometric-Gaussian vortex beam

To suppress the random perturbation of the oceanic channel and improve the performance of link communication, the nonuniformly correlated Hypergeometric-Gaussian (NUCHyGG) vortex beam is first proposed and demonstrated. Based on the extended Huygens-Fresnel principle, the intensity evolution of the NUCHyGG vortex beam in the vacuum is formulated and solved down to a single integral stage. Then, with the aid of Rytov approximate, the orbital angular momentum (OAM) detection probability, bit-error-rate (BER) and average capacity of three different OAM-carrying beams (the Gauss vortex (GV) beam, the Hypergeometric-Gaussian (HyGG) vortex beam, and the NUCHyGG vortex beam) in an absorbent and anisotropic turbulent oceanic channel are comparatively studied. In addition, the parameters optimization of the NUCHyGG vortex beam is made for further enhancing the average capacity. The results display that the NUCHyGG vortex beam exhibits lower crosstalk probability and higher average capacity at a long distance. A ∼7% and ∼14% increment of the average capacity has been demonstrated by the NUCHyGG vortex beam compared with the HyGG vortex beam and the GV beam travel through 100 m, respectively. Furthermore, the optimized beam parameters have the potential to significantly improve the average capacity at long distances. These research results can provide advances in designing the practical OAM-based underwater wireless optical communication (UWOC) system.