Temperature measurement with compact Fabry-Perot Interferometer employing polymer-filled Hollow Core Fiber

Abstract

This research proposes and experimentally demonstrates a polymer-filled Hollow Core Fiber (HCF) based compact Fabry-Perot Interferometer (FPI) for temperature sensing. The two beams: one reflectd at the interface between multimode fiber and the hollow core fiber and the other beam reflected at the interface between the hollow core fiber and the thermosensitive polymer form the Fabry-Perot cavity. The thermosensitive material filled in the core of the HCF acts as the sensing element. The HCF core is partially filled with transparent photopolymer, which has high Thermo-Optic Coefficient (TOC) and Thermo-Expansion Coefficient (TEC) as compared to silica, therefore it can provide high temperature sensitivity. The temperature sensitivity of the proposed FPI sensor can reach up to 53.5 pm/℃. The results indicate that the polymer-filled hollow-core fiber based FPI offers a promising approach for achieving high temperature sensing than pure silica based sensors. The proposed device consists of compact design with easy and low-cost fabrication. Moreover, the temperature measuring device provides stable and linear output response and brings numerous prospects for ocean temperature measurements, food, medical and chemical sensing applications.