Dual Michelson interferometers for distributed vibration detection.

A distributed fiber optic vibration sensor is described, in which two Michelson interferometers are used as phase detectors and two 3×3 couplers are deployed to demodulate the time-varying phase change caused by vibration. The two interferometers are separated by four wavelength division multiplexers. The position of the vibration is obtained by signal correlation, which can be used as a perimeter security sensor to locate the intruder. The experimental results with a 4012 m fiber sensor are discussed.

[1]  Kun Xu,et al.  An intrusion detection sensor based on coherent optical time domain reflector , 2010 .

[2]  Juan C Juarez,et al.  Field test of a distributed fiber-optic intrusion sensor system for long perimeters. , 2007, Applied optics.

[3]  J. Juarez,et al.  Distributed fiber-optic intrusion sensor system , 2005, Journal of Lightwave Technology.

[4]  Alan D. Kersey,et al.  Polarisation-insensitive fibre optic Michelson interferometer , 1991 .

[5]  J. P. Dakin,et al.  Real-time location of multiple time-varying strain disturbances, acting over a 40-km fiber section, using a novel dual-Sagnac interferometer , 2001 .

[6]  洪小斌 Hong Xiaobin,et al.  A Brillouin Optical Time Domain Analysis Based Distributed Fiber Optic Intrusion Sensor System , 2010 .

[7]  Alan B. Tveten,et al.  Passive stabilization scheme for fiber interferometers using (3×3) fiber directional couplers , 1982 .

[8]  J L Santos,et al.  Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements. , 1995, Applied optics.

[9]  Pieter L. Swart,et al.  Merged Sagnac-Michelson interferometer for distributed disturbance detection , 1997 .

[10]  A. Kersey,et al.  Optimization and stabilization of visibility in interferometric fiber-optic sensors using input-polarization control , 1988 .

[11]  Beatrys M. Lacquet,et al.  Modified Sagnac/Mach-Zehnder interferometer for distributed disturbance sensing , 1998, Pacific Northwest Fiber Optic Sensor.

[12]  Xiaoyi Bao,et al.  Distributed Vibration Sensor Based on Coherent Detection of Phase-OTDR , 2010, Journal of Lightwave Technology.

[13]  Xiaojun Fang,et al.  A variable-loop Sagnac interferometer for distributed impact sensing , 1996 .

[14]  Pieter L. Swart,et al.  Distributed dual‐wavelength Sagnac impact sensor , 1998 .

[15]  I. Claesson,et al.  Comparison between whitened generalized cross correlation and adaptive filter for time delay estimation with scattered arrays for passive positioning of moving targets in Baltic Sea shallow waters , 2005, Proceedings of OCEANS 2005 MTS/IEEE.

[16]  X. Bao,et al.  Distributed optical fiber vibration sensor based on spectrum analysis of Polarization-OTDR system. , 2008, Optics express.