High-Sensitivity Fabry–Perot Interferometer High-Temperature Fiber Sensor Based on Vernier Effect

Abstract

A novel sensitivity-enhanced intrinsic fiber Fabry-Perot interferometer (IFFPI) high temperature sensor based on a hollow-core photonic crystal fiber (HC-PCF) and modified Vernier effect is proposed and experimentally demonstrated. The compact all fiber IFFPIs are easily constructed by splicing one end of the HC-PCF to a leading single mode fiber (SMF) and applying an arc at the other end of the HC-PCF to form a pure silica tip. The Vernier effect is formed by three beams of lights reflected from the SMF-PCF splicing joint, and the two air/glass interfaces on the ends of the collapsed HC-PCF tip, respectively. This Vernier effect based fiber sensor can stand with high temperature up to 1200°C, in this work, and experimental results exhibit good linearity, stability and repeatability. The temperature sensitivity can be further enhanced by reducing length of pure silica tip-that is, simply optimizing the discharge time and intensity. The fabrication of the sensitivity-enhanced IFFPI is straightforward, reproducible and low cost, which shows a potential for practical applications in various industrial processes.