Distributed fiber-optic acoustic sensor based on a Sagnac interferometer with detection of exposure at the threshold signal level

Authors: Choban T.V.
Published in issue: #9(62)/2021
DOI: 10.18698/2541-8009-2021-9-732
Category: Instrument Engineering, Metrology, Information-Measuring Instruments and Systems | Chapter: Laser and opto-electronic systems
Keywords: оptical fiber, acoustic sensor, security system, Sagnac interferometer, fiber optic cable, wavelength multiplexing, polling algorithm
Published: 06.09.2021

The operation principle of a distributed fiber-optic acoustic sensor based on the Sagnac interferometer is described and the prospects of its application for solving problems of extended objects protection are demonstrated. A circuit of such a sensor based on two loops created using wavelength multiplexing is proposed, which makes it possible to implement a sensor system based on four cable fibers, which provides compactness and simplifies its installation along the protected perimeter. An algorithm for processing the data obtained from the sensor is also presented, which ensures high accuracy in determining the location of the impact: according to the results of laboratory experiments with a total length of the sensor fiber of 50 km, the error was 13 m.

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