Fiber Optic Distributed Acoustic Sensor Research Articles

Tracking a human walker with a fiber optic distributed acoustic sensor

Traditional ground sensors can be used as security systems to detect third party intrusion, but are costly and cumbersome to scale up to cover a large area. Fiber optic distributed acoustic sensing (DAS) offers a solution that economically and instantaneously monitors up to 40 linear km of a border or perimeter with a single system. The output of the OptaSense third generation fiber interrogation unit is spatially dense, coherent, and exhibits characteristics expected of traditional strain sensors. In this paper, DAS data are shown to indicate a walker’s directionality and support beamforming algorithms for localization.

Design of the fiber optic distributed acoustic sensor based on Michelson interferometer and its location application

A multiplexing method for a fiber optic acoustic sensor is proposed by arranging the working point of Michelson interferometer to improve the temporal resolution of reading the distributed sensor. The slope difference of two series sensors is extracted electrically and is employed to bias the working point. This characteristic is used to separate each sensor from one single data stream by the time difference it takes the acoustic signal to arrive at two sensors. Location application with the verification of the commercial piezoelectric transducer (PZT) proves its efficiency. The stress location is resolved to 5.6 cm at the 54-cm region in one channel.