Ultrahigh Sensitivity Surface Plasmonic Resonance Temperature Sensor Based on Polydimethylsiloxane-Coated Photonic Crystal Fiber

We propose and demonstrate a compact optical fiber temperature sensor based on surface plasmon resonance with high sensitivity and high figure of merit. This optical fiber temperature sensor uses a new photonic crystal fiber designed by us, which is realized by coating a gold film on the polished plane of the photonic crystal fiber and coating the high thermo-optical coefficient material polydimethylsiloxane on the outer surface of the fiber. Small changes in the refractive index of the polydimethylsiloxane due to temperature variations will affect the plasmon pattern, which in turn leads to a change in the measured transmission spectrum. Our numerical results show that the maximum achievable temperature sensitivity of this optical fiber temperature sensor in the range of 60–100 °C is 38 nm/°C, and the maximum refractive index sensitivity and figure of merit are 84444.4 nm/RIU and 603.175 RIU⁻¹, respectively. This is better than the existing various types of PCF temperature sensor. The proposed temperature sensor has the advantages of stable structure, ultra-high temperature sensitivity, and small size. It has good application potential in the field of high-precision temperature control, environmental temperature detecting.