Temperature Sensor Based on Side-Polished Two-Core Fiber Michelson Interferometer

A temperature sensor based on a side-polished two-core fiber (SPTCF) Michelson interferometer (MI) was demonstrated. The temperature sensor is composed of a standard single-mode fiber (SMF), a segment of tapered TCF, and SPTCF coated with polydimethylsiloxane (PDMS). When the temperature changes, the effective refractive index (RI) of the polished core (PC) changes, resulting in the shift of interference fringes to measure the ambient temperature. The experimental results show that the temperature sensor has a sensitivity of up to 694.3 pm/°C in the range of 25–75 °C, meanwhile the device is minimally affected by environmental humidity. With the advantage of low cost, strong stability, simple structure, good reproducibility of fabrication and humidity insensitivity, the sensor has great potential application in industrial, chemical, pharmaceutical and other fields.