Distributed fiber-optic acoustic sensing system and signal processing method using the same

A distributed fiber-optic acoustic sensing system, comprising

• a distributed fiber-optic acoustic sensor comprising a plurality of sensing units along an axial direction, wherein the distributed fiber-optic acoustic sensor comprises
• a distributed fiber-optic sensor based on a sweep frequency pulse and a pulse compression technology,
• an optical frequency domain reflectometer, and
• one or more of phase-sensitive optical time-domain reflectometers based on an ultra-narrow pulse or coherent detection, and
• a sensing optical fiber,
• wherein the distributed fiber-optic acoustic sensor is connected to the sensing optical fiber and is used for emitting a detection light pulse to the sensing optical fiber, collecting and demodulating sound fields of signal sources sensed along the sensing optical fiber;
• a total number of the sensing units in the axial direction of the distributed fiber-optic acoustic sensor is L, the sensing units are divided into M subunits in the axial direction, and the number of the sensing units in each subunit is N, L=M×N, and the sensing units in each subunit are used for spatially coherent combination of sound field signals obtained by detection;
• and
• spatial resolution of the distributed fiber-optic acoustic sensor is centimeter-level or higher.