Experimental Feasibility Study of Fiber Optic Extrinsic Fabry-Perot Interferometric Sensor for Civil Structures and other Applications

An experimental bench set up of a fibre optic Extrinsic Fabry-Perot Interferometer (EFPI) sensor was realised and its feasibility demonstrated in an open configuration. The basic interferometric coupling between the sensing and reference reflections from a Fabry Perot (FP) air cavity realised between two fibre ends was so achieved that the sensor exhibits extreme sensitivity to external disturbances. The study reports about the salient features, scope, operating principle, and details of the experimental set-up of a fibre optic EFPI. The results of qualitative studies undertaken for sensing vibrations due to external disturbances under different situations and its further refinement/modifications for applications in health monitoring of structures are also discussed.