Simultaneous measurement of refractive index and temperature based on a core-offset Mach-Zehnder interferometer

We demonstrated an optical fiber sensor with high sensitivity of temperature and refractive index, we can use it to measure temperature and refractive index simultaneously. The sensing head consists of a section of multimode fiber (MMF) and a section of multi-core fiber (MCF), which is connected between two segments of single-mode fibers to form a Mach-Zehnder interferometer (MZI). A short section of MCF and standard single-mode fiber was misaligned splicing. The sensitivity of temperature and refractive index obtained by experimental results is 52.3 pm/ °C and 11.22 dB/RI, respectively. Due to the use of different demodulation methods, the sensor can overcome the cross contamination problem of measuring the refractive index of the temperature. What's more, the sensor is small in size (only about 3mm), simple in structure and easy to fabricate.