Study of simultaneous measurement of temperature and pressure using double fiber Bragg gratings with polymer package

A simple and practical method to simultaneously measure pressure and temperature using a double fiber Bragg grating (FBG) sensor is presented in which a double FBG is coated in a particular metal tube by a special polymer. In this manner, the inaccuracy induced by the mismatch of pressure and temperature sensitivity can be overcome effectively. The experimental results indicate that this scheme can measure pressure and temperature simultaneously. The temperature and pressure inaccuracy of sensors is about 0.5°C and 0.5 MPa, respectively, within the measuring range of 20 to 100°C and 0 to 20 MPa.