This study presents an innovative methane gas sensor design based on anti-resonant hollow-core fiber (AR-HCF) technology, optimized for high-precision detection at 3.3[Formula: see text]. Our numerical analysis explores the geometric optimization of the AR-HCF's structural parameters, incorporating real-world component specifications. The proposed design features a 65[Formula: see text] diameter hollow core surrounded by seven silica rings. We achieved significant improvements in confinement loss and optical power distribution through progressive structural modifications. The optimized structure demonstrated a confinement loss of [Formula: see text] and over 95% optical power confinement in the hollow core. Our model predicts a relative sensitivity of [Formula: see text], a response time of 5.4 s, and a theoretical detection threshold of 2.24 ppm. The limit of detection (LoD) was estimated to be 3.8 ppbv, and the normalized noise equivalent absorption (NNEA) coefficient was [Formula: see text]. The sensor response exhibited excellent linearity over its operating range, with an R value of 0.9917 in the critical concentration range. These findings highlight the potential of our AR-HCF-based methane sensor design for real-time gas monitoring applications.
