High sensitivity temperature sensor based on a polymer filled hollow core optical fibre interferometer

A high-sensitivity temperature sensor based on a singlemode-multimode-polymer filled hollow core fibre-multimode-singlemode (SMHMS) fibre structure is proposed. This sensor was made from a short section of hollow core fibre filled with a high thermo-optic coefficient (TOC) polymer with a refractive index close to that of the fibre cladding, fusion spliced between two singlemode-multimode (SM) fibre structures. This sensor effectively improves the temperature sensitivity by over 200 times by comparison to a conventional singlemode-multimode-singlemode (SMS) fibre structure. In this report, we experimentally demonstrate that the proposed sensor provides a high temperature sensitivity of 2.16 nm/°C.