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Proceedings Paper

Distributed fiber optic pressure/seismic sensor for low-cost monitoring of long perimeters
Author(s): Kyoo Nam Choi; Juan Carlos Juarez; Henry Fuller Taylor
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Paper Abstract

The use of an optical fiber as a distributed sensor for detecting, locating, and (with suitable signal processing) classifying intruders is proposed. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer (Φ-OTDR). Light pulses from a cw laser with a narrow (kHz range) instantaneous linewidth and low (MHz/min range) frequency drift are injected into one end of the single mode fiber, and the backscattered light is monitored with a photodetector. Results of analyses and experimental studies to establish the feasibility of the concept are described. Simulations predict a range of 10 km with 35 m range resolution and 30 km with 90 m range resolution. Experiments indicate adequate (several π-rad) phase changes are produced by intruders on foot for burial depths in the 20 - 40 cm range in sand and in clay soils. A phase perturbation in a fiber has been detected and located in a laboratory demonstration of the Phi-OTDR using an Er:fiber laser as the light source. This technology could in a cost-effective manner provide enhanced perimeter security for nuclear power plants, electrical power distribution centers, storage facilities for fuel and volatile chemicals, communication hubs, airports, government offices, military bases, embassies, and national borders.

Paper Details

Date Published: 18 September 2003
PDF: 8 pages
Proc. SPIE 5090, Unattended Ground Sensor Technologies and Applications V, (18 September 2003); doi: 10.1117/12.484911
Show Author Affiliations
Kyoo Nam Choi, Incheon City College (South Korea)
Juan Carlos Juarez, Texas A&M Univ. (United States)
Henry Fuller Taylor, Texas A&M Univ. (United States)


Published in SPIE Proceedings Vol. 5090:
Unattended Ground Sensor Technologies and Applications V
Edward M. Carapezza, Editor(s)

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