Abstract
In this paper, we use two methods to research the propagation characteristics of a Hypergeometric-Gaussian (HyGG) vortex beam under oceanic turbulence. One is numerical calculation based on the Rytov approximation theory, where the theoretical detection probability equation of the HyGG vortex beam propagating through oceanic turbulence is derived. The other is numerical simulation based on random phase screens model of oceanic turbulence, where the influences generated by oceanic turbulence on the phase and intensity of the propagation beam as well as the propagation of the beam through several independent phase screens, kept at the same distance, have the same effect. The effects of oceanic turbulence parameters and initial beam parameters on the detection probability of the HyGG vortex beam at the receiver are discussed. The results of theoretical derivation are well in agreement with those of numerical simulation, which demonstrated that the numerical simulation method could effectively simulate the complex theoretical derivation. Both results show that with higher dissipation rate of kinetic energy per unit mass of fluid, smaller dissipation rate of mean-squared temperature and lower temperature-salinity contribution ratio comes the better detection probability. Meanwhile, a HyGG vortex beam with smaller topological charge and longer wavelength has a superior turbulent resistance property. It provides a promising way to estimate the propagation characteristics of the optical beams in an underwater environment.
Highlights
In recent years, researches on underwater optical communication (UOC) have attracted much attention, and the need for large capacity and high speed UOC becomes more urgent due to the growing demand of human activities for scientific research and exploration in an underwater environment [1]
Because some theoretical derivations are difficult to obtain analytical solutions and the underwater experimental environment is difficult to build, an intuitive and effective method called numerical simulation based on random phase screens model of oceanic turbulence is widely employed to analyze the evolution properties of vortex beams in an underwater environment [18,19,20]
We use the two methods from the second and the third section to investigate the influences of different oceanic turbulence parameters and initial beam parameters on the detection probability when HyGG vortex beam is passing through oceanic turbulence channels, with the performance of the two methods compared through the research
Summary
Researches on underwater optical communication (UOC) have attracted much attention, and the need for large capacity and high speed UOC becomes more urgent due to the growing demand of human activities for scientific research and exploration in an underwater environment [1]. The existing studies have shown that when the beams carry OAM propagate through the underwater channel, OAM-spectrum would be spread and the crosstalk would be generated between the adjacent OAM modes All these seriously limit the performance of OAM-based UOC system. Because some theoretical derivations are difficult to obtain analytical solutions and the underwater experimental environment is difficult to build, an intuitive and effective method called numerical simulation based on random phase screens model of oceanic turbulence is widely employed to analyze the evolution properties of vortex beams in an underwater environment [18,19,20]. The extra contribution of this paper is that we use a different method of numerical simulation based on random phase screens model of oceanic turbulence to study the same problem in Ref. The extra contribution of this paper is that we use a different method of numerical simulation based on random phase screens model of oceanic turbulence to study the same problem in Ref. [27] and obtain highly consistent results, providing an effective way for similar studies when there is no direct theoretical solutions and experiments cannot be carried out
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
