Positioning of Turbulence-Distorted Laser Spot for Underwater Optical Wireless Communication

For underwater optical wireless communication, the maximum achievable transmission rate and distance are limited by the high attenuation of water and transmitter-receiver misalignment caused by turbulence. In this paper, we propose a Fourier phase algorithm to localize the laser spot at the receiver, and study the effect of underwater turbulence on the alignment accuracy for a camera-based laser tracking system. Experimental results based on a 10-meter water tank demonstrate the feasibility of the algorithm and improvements in standard deviation of estimated deflection angle as compared with the traditional methods.