Highly-Sensitive Fiber Temperature Sensor Based on Photopolymer Probe and Vernier-Like Effect

Abstract

A highly sensitive fiber temperature sensor based on Vernier-like effect and composite Fabry-Perot interferometers (FPIs) constructed with photopolymer probe is proposed. The composite FPIs consists of two photopolymer probes and form the composite interference cavities based on photopolymer and air, in which the two sides of the air interference cavity are photopolymer. Therefore, both interference cavities are sensitive to temperature and their free spectral ranges (FSR) are close enough to meet the conditions of Vernier-like effect. The temperature sensitivity of the sensor measured as high as -90nm/℃, which is 30 times the temperature sensitivity of FPI based on a single photopolymer probe. In addition, in the preparation process, the photopolymer probe of the sensor is directly attached to the end face of the fiber to form the photopolymer waveguide, which makes the sensor simpler in structure and lower in manufacturing cost.

Keywords: Optical fiber temperature sensor, photopolymer probe, Vernier-like effect, high 
sensitivity