A Highly Sensitive Temperature Sensor Based on a Liquid-Sealed S-Tapered Fiber

A highly sensitive temperature sensor based on the liquid-sealed S fiber taper (SFT) in a capillary is proposed and experimentally demonstrated. The temperature independent SFT is turned into a sensitive temperature sensor by the thermo-optic effect of the RI liquid and the thermal expansion of the sealant. The total length of the device is 10 mm, which can be further shortened to 1 mm if necessary. The temperature sensing mechanism of the liquid-sealed SFT is analyzed in detail and experimental results show the sensitivity reaches as high as -1.403 nm/°C. The temperature sensitivity contributions from different mechanisms are also obtained experimentally.