Temperature sensing by hybrid interferometer based on Vernier like effect

Abstract

Abstract A temperature sensitive hybrid interferometer is developed and tested experimentally. The hybrid interferometer consists of a Michelson interferometer (MI) cascaded with a Fabry-Perot interferometer (FPI). It is fabricated by successively fusion splicing a single-mode fiber (SMF), a small section of multi-mode fiber (MMF), double side hole fiber (DSHF) and hollow Core fiber (HCF) together. The end of the HCF is filled with a thermosensitive polymer to form a reflecting surface of the FPI. The free spectral range of the MI and the FPI are designed to similar so that the Vernier-like effect can be generated. The Vernier Effect and the high thermal expansion coefficient of the polymer filled into the HCF enhance the temperature sensitivity of the hybrid interferometer. The maximum temperature sensitivity of 710.9\xa0pm/°C has been achieved through experiments, which is much higher than silica-based temperature sensors.