Temperature sensor based on tapered no-core fiber coated with PDMS

This study proposed a microstructural temperature sensor based on tapered No-Core Fiber (NCF) coated with polydimethylsiloxane (PDMS). A cascaded single-mode–no-core–single-mode microstructure was fabricated using NCF instead of traditional multimode fiber. The NCF was tapered with its cone area of 0.12cm in the length and approximately 60 μm in the diameter. The main function of this taper region was to enhance the evanescent field as a result sensitively response to changes in the surrounding refractive index. PDMS was coated on the surface of tapered NCF as its cladding environment. When the ambient temperature changes, the refractive index of PDMS will change, which will result in optical path change and interference spectrum drift. Experimental results show that the temperature sensitivity of the sensor is 201.3pm / °C , and its linear response reaches 99.97% in the range of 45 °C to 70 °C . It has a good application prospect in temperature detection with the advantages of high sensitivity, simple structure, and convenient manufacture.