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Proceedings Paper

High resolution underwater fiber optic threat detection system
Author(s): Alexander Berger; Shalmon Hermesh; Eugene Durets; Lothar U. Kempen
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Paper Abstract

Current underwater protection systems are complex expensive devices consisting of multiple electronic sensing elements. The detection and identification of divers and small submerged watercraft requires very high image resolution. The high price of an array of conventional piezoelectric transducers and associated electronic components makes this solution feasible for localized implementations, but the protection of large stretches of coastline requires a different approach. We present a novel multichannel sonar design that augments current active sonar transducers with a passive fiber-optic multichannel acoustic emission sensing array. The system provides continuous monitoring of the acoustic wave reflections emitted by a single projector, yielding information about the size and shape of approaching objects. A novel fiber hydrophone enclosure is utilized to dramatically enhance the sensor response to the sonar frequency, while suppressing out-of-band sound sources and noise. The ability of a fiber hydrophone to respond to acoustic emissions is based on established fiber Bragg grating sensing techniques. In this approach, the energy of an acoustic wave is converted into the modulation of the in-fiber optical transducer's optical properties. The obtained results demonstrate significant response of the designed fiber optic hydrophone to the incident acoustic wave over the frequency domain from 1-80 kHz. Our approach allows selective tuning of the sensor to a particular acoustic frequency, as well as potential extension of the spectral response to 300- 400kHz.2

Paper Details

Date Published: 20 October 2006
PDF: 8 pages
Proc. SPIE 6371, Photonic Sensing Technologies, 63710I (20 October 2006); doi: 10.1117/12.696911
Show Author Affiliations
Alexander Berger, Intelligent Optical Systems, Inc. (United States)
Shalmon Hermesh, Intelligent Optical Systems, Inc. (United States)
Eugene Durets, Intelligent Optical Systems, Inc. (United States)
Lothar U. Kempen, Intelligent Optical Systems, Inc. (United States)


Published in SPIE Proceedings Vol. 6371:
Photonic Sensing Technologies
Michael A. Marcus; Brian Culshaw; John P. Dakin, Editor(s)

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