Abstract:

Over the past 7 years there have been a number of impressive demonstrations of fiber-optic acoustic sensor systems with surveillance grade capabilities. These demonstrations range from single-element and small six-element arrays tests conducted in the Arctic (1990 and 1992), to a 128-channel capacity (64-populated channels), horizontal line array deployed off Point Loma in 1996. These fixed, surveillance arrays have wider bandwidths and larger dynamic ranges that their piezoceramic counterparts. As well as fixed arrays, hull-mounted array demonstrations (such as the lightweight wide aperture array) have met the stringent Navy performance specifications while eliminating all the outboard electronics to reduce the systems life-cycle costs. The lightweight planar array approach is a viable candidate for the NSSN WAA. To reduce system costs further, planar array approaches using fiber optic appear to be the candidate of choice for the next generation of submarine mounted arrays. The other area attracting attention is that of the all-optical towed array, where the reduction in wet-end cost is the prime driver. In this system concept, engineering functions required for the operation of the array are accomplished by a suite of fiber-optic sensors for temperature, pressure, heading, roll, pitch, and strain.