Simultaneous measurement of temperature and liquid refractive index based on fiber open Fabry-Pérot cavity and Bragg grating

Abstract:

A temperature and refractive index sensor based Fiber Bragg Grating (FBG) end surface cascade open Fabry-P?rot (FP) cavity has been designed and demonstrated experimentally. The open FP cavity has been fabricated on the end face of a FBG by dislocation fusion in this work, the open FP cavity could be used for refractive index sensing, the temperature is measured by cascading a FBG. The working principle of the sensor and the method of improving the sensitivity are analyzed by theoretical simulation. The refractive index sensitivity of the sensor is 1108.4nm/RIU, while the maximum fluctuation of the sensor stability experiment detection is 0.005nm, the results show that it has satisfactory characteristics. The sensor is a compact all-fiber structure, so it has potential applications in the field of temperature refractive index sensing, such as biomedical, capacitor electrolyte detection.

Key words:Refractive index sensing, Temperature sensing, Fiber Bragg Grating, Open Fabry-P?rot interferometer.