Paper
9 December 1999 Fiber laser hydrophone array
David J. Hill, Phillip J. Nash, David A. Jackson, David J. Webb, S. F. O'Neill, Ian Bennion, Lin Zhang
Author Affiliations +
Abstract
In recent years growing interest has surrounded the development of fiber laser sensors (FLS). This is due to their ultra high sensitivity to temperature and strain as well as their ability to be multiplexed along a single fiber using WDM techniques. It is their extreme sensitivity that has led to them being considered as acoustic pressure sensors rather than standard fiber Bragg gratings. The work presented here describes the development of an array of FLS configured as hydrophones. We discuss the design of the single mode fiber laser used throughout our system; comparing examples based upon distributed Bragg reflectors (DBR) and distributed feedback (DFB). In addition we discuss both the theoretical and experimental acoustic sensitivity enhancements obtained by the application of an elasto-plastic coating to the FLS. The array configuration is described, as is the heterodyne interrogation scheme using an unbalanced Mach-Zehnder interferometer with WDM channel selection. Results from the measurement of the minimal detectable acoustic signal of a bare fiber laser are shown to be -69 dB re.Pa/(root)Hz at 1 kHz when using a 200 m path imbalanced readout interferometer. Further gains in the sensitivity due to the application of various coatings are reported, as is a full characterization of an array of fiber laser hydrophones. Finally we discuss the future research of the FLS, and the areas in which the technology is particularly applicable.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David J. Hill, Phillip J. Nash, David A. Jackson, David J. Webb, S. F. O'Neill, Ian Bennion, and Lin Zhang "Fiber laser hydrophone array", Proc. SPIE 3860, Fiber Optic Sensor Technology and Applications, (9 December 1999); https://doi.org/10.1117/12.372963
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CITATIONS
Cited by 81 scholarly publications and 2 patents.
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KEYWORDS
Fiber lasers

Sensors

Acoustics

Signal detection

Phase measurement

Fiber Bragg gratings

Coating

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