Double D-shaped optical fiber temperature and humidity sensor based on ethanol and polyvinyl alcohol

Abstract

In the paper, a double D-shaped optical fiber temperature and humidity sensor based on surface plasmon resonance (SPR) is reported. The two flat surfaces of the double D-shaped optical fiber are respectively coated with ethanol as a temperature-sensitive material and polyvinyl alcohol (PVA) as a humidity-sensitive material. The sensing properties of the structure were numerically simulated by the finite element method (FEM). The influence of the structural parameters on the sensing performance was investigated. The results show that the temperature sensitivity reaches 2.9 nm/℃ in the range of 10–70 ℃, and the humidity sensitivity reaches 11.6 nm/%RH in the range of 20−80%RH. A high linearity of 0.9933 and 0.9998 are obtained, respectively. This structure will promote the development of high-performance dual-parameter sensors.