Influence of oceanic turbulence on propagation of the Gaussian pulsed X wave carrying orbital angular momentum

Abstract

Abstract By developing the two-frequency mutual coherence function of the vortex wave, we derive the analytical expression of the coherence function of the Gaussian pulsed X wave carrying orbital angular momentum propagating in the anisotropic turbulence of ocean. Employing this coherence function, we establish the received probability density of orbital angular momentum modes including the time factor. Applying this probability density, we investigate the influences of turbulence and beam parameters on the received signal probability. Our results show that the anisotropic oceanic turbulence with a smaller ratio of temperature and salinity contributions to the refractive index spectrum, higher rate of dissipation of kinetic energy per unit mass of fluid, larger inner scale, or lower dissipation rate of the mean-squared temperature causes the larger signal probability density; the Gaussian pulsed X wave with large sources transverse size, small Bessel cone angle, low orbital angular momentum quantum number or broad initial half-pulse width has stronger resistance to oceanic turbulent interference. This work provides theoretical preparation for the implementation of the spatiotemporal communication with ultrafast vortex pulse.