Abstract

We present and demonstrate an ultra-sensitive temperature sensor based on an isopropanol-sealed Mach-Zehnder Interferometer (MZI). The structure is composed of a refractive index sensitive MZI that encapsulated in a capillary tube filled with isopropanol. The isopropanol with a high thermo-optic coefficient, which directly constitutes the sensing arm of the encapsulated MZI. When the temperature changes, the optical path difference between the two MZI’s interference arms changed greatly due to the drastic change in the refractive index of isopropanol, leading to wavelength shift significantly. Experimental results show an ultra-high sensitivity of 7.3819 nm/°C with good linearity. In addition, the temperature sensor is insensitive to the surrounding refractive index change. Excellent performance demonstrates it a good candidate for temperature measurement.

© 2020 The Author(s)