New generation of Fabry-Perot fiber optic sensors for monitoring of structures

This paper reports on a new generation of Fabry-Perot fiber optic sensors to be used in parallel or in replacement of conventional instruments for monitoring of structures. The new generation of sensors is based on a unique fiber optic strain sensor that represents a breakthrough in fiber optic sensing. The novel technique is based on extrinsic Fabry-Perot white-light interferometry which offers outstanding accuracy and repeatability. Furthermore, all sensors are completely immune to lightning surcharges which opens new possibilities in the field of reliable long term structure monitoring. Instruments such as piezometers, embedment strain gages, surface strain gages, temperature sensors and displacement transducers are all available in Fabry-Perot fiber optic version. Furthermore, all these instruments use a common multimode optical fiber to carry the signal to the readout units and multi-channels dataloggers. Both static and dynamic measurements are possible with this technology. The paper presents results of laboratory and field studies on fiber optic sensors mentioned above including integrated fiber optic sensors in carbon and glass fiber reinforced polymer. A case study of bridge strain monitoring with Fabry-Perot sensors is also reported.