Keynote - Fibre-Optic Distributed Sensing for Infrastructure Objects and Near-Surface Monitoring

Fibre-optic distributed acoustic sensing (DAS) has developed into a technology that has found application in many different scientific, engineering and industrial fields, where dynamic strain measurements are used to analyze the elasto-dynamic behaviour of an object or medium. Using a highly coherent laser source, a standard telecom-grade optical fibre, usually utilized for network data transmission, can be turned into an array with tens of thousands of virtual sensors. Many of the advanced analysis algorithms, such as feature extraction, or various forms of near-surface or subsurface imaging, machine learning or AI, require spatially and temporally well-sampled wave field recordings with fine sampling intervals and large spatial coverage. Such a type of data acquisition is only possible, if the individual sensors can be deployed cheaply on a large scale; and can be operated continuously without the need for power and data storage at each sensor location. Distributed fibre-optic sensing is a sensing technology that enables such pervasive sensor networks and provides continuous data streams of high resolution and coverage to feed real-time or offline analysis algorithms. We demonstrate such possibilities with a transport system infrastructure recording of train movement while obtaining earthquakes recordings and measuring near-surface conditions.