Investigation of plasmonic properties of graphene multilayer nano-ribbon waveguides

In this paper, we investigate the plasmonic properties of a graphene-silica-silicon (G-SiO₂-Si) multilayer nano-ribbon waveguide in the mid-IR spectral range using the finite element method. Numerical results show that single-mode operation and modal cut-off properties of the G-SiO₂-Si are highly sensitive to the width and chemical potential. In particular, we demonstrate that by properly tuning the geometric and material parameters of the spacer layer or by decreasing the operation frequency, the graphene-based waveguide exhibits a propagation length higher than that of its metal-based counterpart. We believe that this study will provide a valuable reference for designing ultra-compact and low-loss graphene-based novel integrated plasmonic devices.