Bi-static LIDAR systems operating in the presence of oceanic turbulence

TL;DR

This paper develops a comprehensive theoretical framework to predict how oceanic turbulence affects light beams in bi-static LIDAR systems, considering various optical wave properties and target types, enhancing understanding of underwater optical communication.

Contribution

It introduces a novel theory combining Huygens-Fresnel integrals and ABCD matrices to model light propagation through oceanic turbulence for diverse optical waves and targets.

Findings

Analyzes the evolution of beam spectral density and coherence in turbulent water.

Incorporates turbulence effects into bi-static LIDAR return analysis.

Provides a predictive model for underwater optical system performance.

Abstract

Optical turbulence occurring in the oceanic waters may be detrimental for light beams used in the short-link communication and sensing systems, and, in particular, in underwater LIDARs. We develop a theory capable of predicting the passage of light beams through the bi-static LIDAR systems, for a wide variety of optical waves, including partially coherent and partially polarized, and for a wide family of targets. Our theoretical framework is based on the Huygens-Fresnel integral adopted to random media and optical systems described by the $4\times4$ ABCD matrices. The treatment of oceanic turbulence relies on the recently introduced power spectrum model of the fluctuating refractive-index [Opt. Express 27, 27807 (2019)] capable of accounting for different average temperatures of water. We first analyze the evolution of the second-order beam statistics such as the spectral density and the degree of coherence of the beam on its single pass propagation and then incorporate this knowledge into the analysis of the bi-static LIDAR returns.