Detection and Quantization Technique of Optical Distributed Acoustic Coupling Based on φ-OTDR

The detection of multiple acoustic disturbances by optical fiber is a hot research topic in the field of optical fiber sensing. This paper considers adopting an optical distributed acoustic sensing (DAS) system to detect multiple acoustic disturbances, proposes a new approach to processing the DAS signal based on time-space average in frequency domain, and overcomes the randomness of DAS time domain signal. Finally, it obtains a functional model of single-frequency (50–1 000 Hz) sound pressure level and DAS signal intensity, and also the cut-off frequency of acoustic disturbance is detected by DAS system.