Advances in fiber sensing

In this talk, we will present recent technological advances in fiber sensing applications with long monitoring distances or extending multiple fiber spans. In forward-transmission-based sensing, adaptive beamforming techniques were demonstrated to achieve multi-event vibration sensing in environments with interference and jamming with significant improvements in signal reconstruction, noise reduction, and interference rejection from other locations. For sensing over submarine cables with many fiber spans with repeaters, it is shown that distributed reflection from Rayleigh scattering can be detected with sufficient SNR for fiber sensing using HLLB paths. In particular, longitudinal averaging of received Rayleigh scattered signals can facilitate state-of-polarization-based, multi-span sensing using eigenvalue method.