Development of a Robust, High Speed, Underwater Optical Communications System for Ocean Science

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

Communication underwater is severely limited when compared to communications in air because water is essentially opaque to electromagnetic radiation except in the visible band. Even in the visible band, light penetrates only a few hundred meters in the clearest waters and much less in waters made turbid by suspended sediment or high concentrations of marine life. Consequently, acoustic techniques have been developed for underwater communication systems and now represent a relatively mature and robust technology. Acoustic systems, however, offer limited data rates and significant latency (due to the speed of sound in water). The PI?s request funding to complete the development of an optical communication system that complements existing acoustic systems resulting in an underwater communications capability offering high data rates and low latency in clear water combined with long range and robustness in the presence of high turbidity. This combination of capabilities will make it possible to operate self-powered ROVs from support vessels without requiring a physical connection to the ROV. This in turn will simplify operations, reduce costs and reduce the requirement for dynamically positioned vessels. In addition, it will be possible to transfer large data files from fixed sensors using AUVs (or ROVs) as data mules, to transfer real-time video from untethered vehicles for inspection, identification and other related operations, and to provide interconnectivity for dense arrays of underwater sensors without the need for expensive and difficult to install undersea cables. Broader Impacts High rate optical modems will be an important adjunct to cabled observatories and acoustic networks. New sensing applications for ROVs will be enabled with video streaming capability. Existing outreach programs to K-12 at WHOI will be leveraged to include the new optical modem development. Reliable, high speed wireless communication is an extremely important "missing link" in underwater research. A good solution to this problem will have wide-reaching impacts on the use of AUVs, sensor networks or wirelessly controlled ROVs in oceanography, will make the deployment of vehicles easier and lower risk, and open up new possibilities.