Recent Advances in Distributed Acoustic Sensing Based on Phase-Sensitive Optical Time Domain Reflectometry

Figure 7

Experimental setup of LFM pulses within a time slightly longer than RTT for distributed vibration measurement of vibration frequencies with sampling times of fractions of RTT of the fiber [30]. AWG: arbitrary waveform generator; AOM: acousto-optic modulator, BPD: balanced photodiode.