Simultaneous measurement of refractive index and temperature by M-Z interferometer cascaded with a FBG

An optical fiber sensor based on fiber Bragg grating (FBG) and Mach-Zehnder interferometer (MZI) is experimentally demonstrated for simultaneous measurement of refractive index (RI) and temperature. It features a single mode-multimode-single mode (SMS) fiber structure and a spherical-shape. The fabricated sensor exhibited sensitivities of FBG and MZI are 0.0098 nm/°C and 0.093 nm/°C, respectively. The sensor possesses the advantages of easy fabrication, good robustness and high sensitivity.