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Fast distributed Brillouin optical fiber sensing based on pump frequency modulation

We present a fast distributed Brillouin optical fiber sensor based on pump frequency modulation. The frequency shift of the probe is fixed, while the pump is fast scanned using an arbitrary waveform generator (AWG). Thus, the bandwidth requirement of the AWG is reduced to several hundred megahertz without any expense to the acquiring speed. Combining with differential pulse width pair (DPP) technology, a vibration measurement is implemented in a 230-m polarization-maintaining fiber with a sampling rate of 2.6 kHz and 50 cm spatial resolution. A vibration signal up to 31 Hz is identified successfully with a strain resolution of 15 µε.