Rytov variance of plane and spherical waves, and scintillation index in weak to strong underwater turbulence

Abstract

As a means of distinguishing the weak and strong irradiance fluctuations of optical beam propagation in turbulence, Rytov perturbation approximation and its later extension make it possible to characterize the transition between turbulence regimes. The closed-form expression of Rytov variance is derived for both plane and spherical waves propagating in underwater turbulence. Scintillation index of plane and spherical waves are also investigated depending on the Rytov variance in weak-moderate-strong underwater turbulence regimes. Moreover, the variation of signal-to-noise ratio (SNR) for an optical wireless communication system operating in underwater turbulent medium is analyzed. Results are presented for various underwater parameters. We believe that researchers may benefit from our results to find the optimum design (e.g. aperture size) and performance (e.g. SNR, bit-error-rate) parameters for an optical wireless communication systems operating in wide range underwater turbulent medium.