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. (C) 2003 society of Photo-Optical Instrumentation Engineers.