Real-time data processing algorithm for phase-demodulation distributed fiber-optic vibration sensor with signal-to-noise ratio over 30 dB

The phase-detection distributed fiber-optic vibration sensor based on time-gated digital optical frequency domain reflectometry has linear response to vibration signals with long measurement distance. However, the computational complexity and large amount of data stream makes it difficult to realize online data processing. This paper introduces the realization of fully pipelined processing system based on field-programmable gate array (FPGA), with which the phase can be extracted in real time. In experiments, an 800 Hz sinusoidal vibration signal is detected along 5 km fibre located at the far end, and the spatial resolution is about 5 m.