Low cost non-adiabatic tapered fiber for high-sensitive temperature sensing

A non-adiabatic tapered fiber sensor was fabricated, and its applications in refractive index (RI) and temperature sensing were investigated in both theory and experiment. The experiment results demonstrated that the tapered fiber sensor with a diameter of 8 μm had RI sensitivity as high as 1800 nm/RIU and temperature sensitivity of about −300 pm/°C. Then, taking advantage of its high refractive index sensitivity property, an improved temperature sensor structure was proposed by encapsulating it in a glass microtube and filling the microtube with high thermo-optical coefficient liquid. This improved sensor structure showed a higher temperature sensitivity of around −900 pm/°C. The improved sensor structure is simple, low cost and easily fabricated. Besides, this temperature sensor has high sensitivity, good mechanical strength and strong anti-disturbance ability.