▎ 摘　　要

In the present communication, a fiber optic biosensor based on surface plasmon resonance (SPR) phenomenon, having bilayers of Ag-Pt with graphene as a sensing layer, is presented. Theoretical simulation is performed to analyze the effect of graphene layers on the sensitivity of the proposed fiber optic surface plasmon resonance (FOSPR) biosensor. The sensing layer graphene onto the bilayer of Ag-Pt is accountable for enhancing the sensitivity of FOSPR biosensor. The trade-off between large sensitivity and large broadening in transmission spectra impose restriction on using the greater number of graphene layers. The refractive index sensitivity of the proposed FOSPR biosensor comes out to be 4216 nm/RIU for the 5 layers of graphene having a large dynamic range of refractive index variation from 1.33 to 1.39.