Compensation for aberrant wavefront in UOWC based on adaptive optics technique employing genetic algorithm

Abstract

Underwater optical wireless communication (UOWC) has attracted extensive attention due to its merits in transmission latency, bandwidth, and security. However, its performance is usually significantly limited by the scattering, absorption, and turbulence effects. Thus, many schemes have been proposed to enhance its performance via various optimizations at the transmitter, but most of them neglected the wavefront optimization at the receiver. Although traditional adaptive optics based on wavefront detection (AOWD) technology employing wavefront phase sensor (e.g. Shack-Hartmann sensors) and compensator (e.g. deformable mirror) was proposed to alleviate wavefront distortion, it introduced extra challenges in miniaturizing receivers for UOWC. Additionally, traditional AOWD technologies usually employed costly and large computing systems,which reduced their feasibility in reality. In this paper, a novel compensation technology is proposed to optimize the distorted wavefront at the receiver based on the wavefront sensorless adaptive optics (WSAO) technique using improved genetic algorithm (GA). Instead of using the wavefront phase-detector, the proposed technology measures the light intensity via a small photo-detector (PD) and outputs voltage signals though the employed GA to manipulate the deformable mirror (DM) for wavefront compensation. The simulation results indicate that the proposed technology effectively improves the intensity distribution and the Strehl Ratio (SR) of the transmission light in UOWC.