Wavelength-Scanning Distributed Acoustic Sensing for Structural Monitoring and Seismic Applications

Abstract

We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks (ANNs) are used for fast and high-resolution strain computation from raw measurement data. The applicability of the method is demonstrated for vibration monitoring of a reinforced concrete bridge. We demonstrate another application example for quasi-static and dynamic measurement of ground deformation and surface wave propagation along a dark fiber in a telecommunication cable.

Keywords

• optical fiber sensor
• distributed acoustic sensor (DAS)
• optical time domain reflectometry
• Rayleigh scattering
• artificial neural networks
• structural health monitoring
• seismic measurement