Long-Range High-Spatial-Resolution Distributed Measurement by a Wideband Brillouin Amplification-Boosted BOCDA

Stimulated Brillouin scattering (SBS)-based distributed fiber optic sensing technique has found pervasive applications in measurement of real-world environmental variables. Its sensing capability, however, is affected by the tradeoff between sensing distance and spatial resolution. Herein, we propose and experimentally verify a wideband Brillouin amplification (WBA)-boosted BOCDA to achieve the high spatial resolution sensing in a longer distance. The WBA is generated by exploiting phase-uncorrelated SBS process between pump and probe waves. Through the WBA, the pump pulses at different scanning frequencies are amplified with the same ratio, which brings distortion-free enhancement of Brillouin signals. The signal-enhancement improves the sensing distance of high spatial resolution BOCDA. As a result, without any additional (Raman/Brillouin) amplification devices, a similar to 0.46 MHz measurement certainty and a 6 cm spatial resolution are achieved over a similar to 40 km sensing range. The proposed method offers a viable solution for the applications that need high-resolution measurement of remote targets.