Vectorial distributed acoustic sensing based on a multicore fiber and phase-sensitive optical time-domain reflectometry

Abstract

A vectorial distributed acoustic sensing (vDAS) system is proposed and demonstrated for distributed two-dimensional vector vibration measurements based on phase-sensitive optical time-domain reflectometry (ΦOTDR). An optical pulse compression (OPC) algorithm was used to achieve high spatial resolution and suppress fading noise, and a Rayleigh-enhanced seven-core fiber (eSCF) was used to magnify the differentials of Rayleigh backscattering (RBS) in various cores undergoing vibrations. A combination of OPC and eSCF allows the system to fully quantify perturbations with a spatial resolution of 1.1 m and a strain resolution of 1.1 pε/√Hz, achieving a maximum acceleration sensitivity of 1.04 mrad/g at 60 Hz and an orientation reconstruction error of 1.92°. The proposed vDAS system can achieve vectorial distributed vibration sensing without the need for specific fiber layouts or complex reconstruction algorithms, increasing its potential for applications in vertical seismic profiles or pipeline inspection.