High sensitivity temperature sensor based on hybrid interferometer fabricated by splicing panda fiber and few mode fiber

A novel hybrid interferometer temperature sensor was designed based on few mode fiber (FMF) and panda fiber (PF). PF forms a Michelson interferometer (MI), and the fusion splicing air-bubble between FMF and PF forms a Fabry-Perot interferometer (FPI). In order to further enhance the sensitivity of the sensor, the thermosensitive material polydimethylsiloxane (PDMS) was coated on the surface of PF of the sensor. When the temperature changes, the resonant peak wavelength of the sensor spectrum shifts significantly, and environmental temperature measurement is achieved by demodulating the resonant peak wavelength drift. The experimental results show that when the sensor is not coated with PDMS, the temperature sensitivity is 103.3 pm/°C. When the sensor surface is coated with 1.5 cm long PDMS, the sensitivity of the sensor reaches 154.3 pm/°C. When the sensor surface is coated with 6.0 cm long PDMS, the sensitivity of the sensor reaches 161.3 pm/°C. The experimental results reveal that coating PDMS on the surface of the sensor can effectively improve the temperature sensitivity. This temperature sensor has a simple structure and high sensitivity, and practical application value.