124km Phase-Sensitive Otdr With Brillouin Amplification

A long-range (124km) fully distributed fiber-optic vibration sensing system is demonstrated, based on phase-sensitive optical time-domain reflectometry (Phi-OTDR) with counter-pumping distributed fiber Brillouin amplification (FBA). FBA significantly enhances the probe pulse signal at the second half of the sensing fiber with less than 10dBm pump power, and its amplification efficiency is demonstrated to be much higher than 26.9dBm counter-pumping Raman amplification. As a result, demodulated intrusion signals along the whole sensing range can keep high signal to noise ratio. The FBA scheme demonstrated in this work can also be incorporated in many other distributed fiber-optic sensing systems for extension of sensing distance.