A Highly Sensitive Dual-Core D-Shape Photonic Crystal Fiber Based on Surface Plasmon Resonance for Methane Sensing

In this study, we introduce a cutting-edge gas sensor exploiting surface plasmon resonance (SPR) in a novel D-shaped photonic crystal fiber (PCF) configuration, tailored for methane detection. The sensor's innovative design incorporates dual-core polished gas access microstructures, optimizing methane-gas interaction surfaces. A gold nanofilm was strategically selected to induce SPR, augmented by a polysiloxane-doped cryptane E overlay for heightened methane sensitivity. To meticulously evaluate sensor performance, we employed a combination of finite element analysis (FEA) and rigorous numerical modeling. These analyses revealed the profound impact of structural parameters on sensor attributes. Our findings highlight a remarkable methane sensing capability, evidenced by a sensitivity of 11.52 nm/% and a figure of merit (FOM) reaching 0.409 within the tested 0–3.5% concentration range, accompanied by a linear response profile—underscoring the system's precision and reliability. This pioneering sensor technology, distinguished by its affordability, simplicity, and real-time monitoring capabilities, charts a new course in the realm of gas leak detection systems, poised to make significant contributions to future safety and environmental monitoring endeavors.