A fibre laser sensor seabed array

We have developed an 8-element fibre laser seabed array demonstrating state-of-theart performance characteristics for a fibre laser sensing system and highlighting the potential capability advantage this technology provides in the underwater sensing domain. The system employs sea-state-zero sensitivity hydrophones with a flat acoustic response over a bandwidth exceeding 5kHz and very low inertial sensitivity. Each hydrophone is pressure compensated to an ocean depth exceeding 80m. The system contains no outboard electronics and virtually no metal components making it extremely light, compact, and low complexity. The array may be deployed up to 4 km from a land or sea based platform. Power is delivered optically via a single 2mm diameter optical fibre lead weighing less than 5kg per km. The same optical fibre also serves as the telemetry link to relay full bandwidth data from all 8 sensors back to the platform.