Highly integrated FP/FBG sensor for simultaneous measurement of strain and temperature under high temperature

Abstract

An inline fiber-optic micro Fabry–Perot (MFP) cavity and a short fiber Bragg grating (SFBG) is overlapped to form a highly integrated MFP/SFBG sensor for simultaneous measurement of temperature and strain under high temperature (300°C). The F-P cavity is fabricated on an all-silica fiber by using the 157nm laser micro-machining technique while the SFBG is written on a GeO₂ doped high temperature photon sensitive fiber at the same position of the MFP cavity. As the MFP cavity and the SFBG have different sensitivity coefficients to temperature and strain, they can be utilized for realization of dual parameters measurement. Experimental results show that simultaneous measurement of strain and temperature is achieved under high temperature up to 300°C.