OAM mode of the Hankel–Bessel vortex beam in weak to strong turbulent link of marine-atmosphere

Abstract

We study the turbulent effects of maritime atmosphere on the propagation of the orbital angular momentum (OAM) modes of a vortex beam. Based on the modified Rytov approximation, we model the effective marine-atmospheric spectrum and the normalized energy weight of the vortex modes of Hankel–Bessel beams in a paraxial marine turbulent channel. Our results show that the intensity of the signal vortex modes of Hankel–Bessel beams in a non-turbulence channel increases with increasing the quantum number of the OAM of vortex modes from one to higher. We can utilize OAM eigenstates of the Hankel–Bessel vortex beam to increase the channel capacity in optical communication of the remote link. The normalized energy weight of signal OAM modes increases and that of crosstalk OAM modes decreases from the worst to the best turbulent maritime climate. The normalized energy weight of signal OAM modes reduces with the increasing of the turbulent outer scale from to and the receiving diameter, but it increases with increasing the turbulent outer scale when the outer scale is greater than . The effects of the inner scale on the normalized energy weight of OAM modes can be ignored. We can mitigate the effects of turbulence by the choice of the longer wavelength and smaller receiver aperture.