Optical fiber sensor for simultaneous measurement of hydrostatic pressure and temperature in soil embankments

An optical fiber sensor for the simultaneous measurement of hydrostatic pressure and temperature in soil embankments is presented. The sensor exploits a dual chambers transduction mechanism and is based on the optical measurement of the differential strain induced in the fiber by temperature and pressure in the two chambers. A prototype has been built and interrogated by means of optical coherent frequency domain reflectometry and the results of a preliminary experimental characterization are presented and discussed. Temperature and pressure sensitivities are approximately -7.1 GHz/°C and -4.4 GHz/kPa, respectively.