Alcohol-filled side-hole fiber based Mach-Zehnder interferometer for temperature measurement

A temperature sensor by using an alcohol-filled side-hole fiber (SHF) based Mach-Zehnder Interferometer (MZI) is proposed and experimentally demonstrated. The SHF-MZI is fabricated by splicing one section of alcohol-filled SHF between two single mode fibers (SMFs). The interference pattern between the core mode and the cladding modes excited at the first fusion splicing point shifts with temperature, due to the temperature-dependent refractive index of alcohol in the SHF, as well as thermo-optic effect and thermal expansion effect of the SHF. Temperature measurement with sensitivity of 105 pm/°C is therefore achieved by detecting resonant wavelength shift of the interference pattern. Meanwhile, the interference properties of the alcohol-filled SHF is investigated and discussed.