Changes of propagation properties of orbital angular momentum for Laguerre-Gaussian beams in weak turbulent ocean

Rytov approximation is used to analyze the turbulence effects on the detection probability, crosstalk probability and spiral spectrum of the orbital angular momentum (OAM) for Laguerre-Gaussian (LG) beams in weak oceanic turbulence. Numerical results indicate that the oceanic turbulence has much stronger effect on the OAM modes than atmospheric turbulence, and the effective range of the signal OAM mode of LG beams is limited only to several decametres in turbulent ocean. Oceanic turbulence induces signal OAM modes detection probability decrease, mode crosstalk, and spiral spectrum spread badly. The effects of oceanic turbulence increase with the increase of OAM angular modes, radial modes, beam width, and the decrease of the wavelength. Longer wavelength can effectively mitigate oceanic turbulence effects. However, blue and green wavelengths are preferred due to the absorption and scattering effects of the oceanic water.