Hybrid underwater optical/acoustic link design

The performance of duplex underwater optical wireless communication systems are limited by back-scattering of the transmitted light. This paper introduces a novel underwater wireless link design using hybrid optical/acoustic as a method to overcome it. The design comprises of highly directive, high-bandwidth optical uplinks from submersed AUVs or divers to a base station and a low bandwidth, wide-angle downlink. The limiting performance factors for the acoustic and optical aspects were found through respective channel modelling and SNRs; the maximum bitrate of the hybrid link is greater than a traditional acoustic link by a factor of 150. Main issues such as susceptibility to natural ocean variation, optical misalignment and acoustic latency are discussed.