A High-Sensitivity D-Shaped Microgroove Photonic Crystal Fiber Gas Sensor Based on Surface Plasmon Resonance

A D-shaped open-ring microgroove photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is proposed for the simultaneous measurement of methane gas concentration and temperature. The sensitive coatings are polysiloxane-doped cryptane E and polydimethylsiloxane (PDMS), and the designed microgroove structure with out-of-hole coating is expected to improve the sensitivity. The finite element method (FEM) is employed to analyze the data numerically, and the results demonstrated that the average sensitivities could reach − 96.57 nm/% for methane concentration in the range of 0.5 ~ 3.0% and − 6.86 nm/°C for methane temperature in the range of 0 ~ 50 °C. Both measurement channels exhibited excellent linearity, making them highly valuable for environmental monitoring and other applications.