An improved tin oxide core mismatch optical fiber sensor and its preparation method

Abstract A sensor was fabricated based on optical gas sensing, the sensitivity of tin oxide to methane via surface adsorption and electromagnetic theory. A 62.5/125 μm standard multimode fibre (MMF) and a 9/125 μm standard single-mode fibre (SMF) were spliced to fabricate a core diameter mismatch-based optical fibre methane sensor with an MM-SM-MM structure. The exposed fibre core areas were coated with graphene-doped tin oxide such that a novel graphene-based optical fibre methane sensor was fabricated. The experimental results show that the sensor exhibited a better linear fitting for greater reproducibility in the detection of low concentrations of methane than did the D-type gas sensor reported previously by the same authors.