Long-distance vector Brillouin optical time-domain analysis sensors using distributed Brillouin amplification with frequency-comb pump parallel demodulation

摘要

We demonstrated a structure for extending repeater-less sensing distance of Brillouin optical time-domain analysis enhanced by distributed Brillouin amplification (DBA-BOTDA) through a combination with the Brillouin phase spectrum (BPS), where parallel demodulation of the frequency-comb pump can be realized. The careful structure design is implemented to perfectly suppress the impacts of various phase noises on long-distance BPS extraction. similar to 98.9 km sensing distance and similar to 6.5 m spatial resolution were demonstrated, with only four times frequency sweeping. The standard deviation of Brillouin frequency shift can be decreased to within similar to 2 MHz by a combination of Brillouin gain spectrum and BPS.