oa C-OTDR Based Quasi-distributed Vibration Sensing Using High Scattering Fiber Segments - Performance for Subhertz Dynamic Strain Events

Distributed vibration sensing (DVS) based on Rayleigh single pulse optical time-domain reflectometry (C-OTDR) is an attractive and robust method for a variety of sensing applications including geosensing. A key issue for the usability of DVS systems is the signal-to-noise ratio (SNR) and thus the feasibility to demodulate a measured signal, especially in the case of small dynamic strain amplitudes. We present a simple method to locally boost the sensitivity of DVS using pairs of fs-laser-written strongly scattering fiber segments.