Distributed Fiber-Optic Acoustic Sensor for Sparse-Wideband Vibration Sensing With Time Delay Sampling

This paper proposes a novel distributed fiber-optic acoustic sensor, which can solve the trade-off between the measurable distance and the maximum detectable frequency. The system is based on time-gated digital optical frequency domain reflectometry combined with time delay sampling method and frequency division multiplexing. In experiments, vibration with frequency up to 13 kHz and 47 kHz are detected simultaneously with 10 kHz pulse repetition rate. The system reached a high signal-to-noise ratio of 25 dB and spatial resolution of 8 m. This system does not require additional hardware equipment and has high flexibility, which could be utilized in specific occasions.