Simultaneous measurement of temperature and refractive index based on microfiber Bragg Grating in Sagnac loop

摘要

In this paper, a simultaneous measurement system of temperature and refractive index (RI) is proposed and demonstrated. The dips in the output spectrum of the proposed sensor are formed by the microfiber Bragg Grating (mFBG) and Sagnac loop. Due to different interference mechanisms, the dual-parameter measurement is realized by mFBG and Sagnac loop with different sensitivities to temperature and RI. Compared with the traditional Sagnac loop sensors, the proposed Sagnac loop with mFBG is much sensitive to surrounding RI. The results show that the temperature sensitivity is 0.033 nm/degrees C and -0.015 dB/degrees C. And the RI sensitivity is 39.30 nm/RIU and 41.51 dB/RIU. The proposed sensor has a simple structure and great potential in biological and chemical fields.