▎ 摘　　要

Outstanding properties of graphene plasmons have attracted their use in various plasmonic devices, ranging from absorbers to two-qubit quantum logic gates. Here, we investigate plasmonic properties (the effective mode index and propagation length) of a cylindrical graphene-based waveguide (GBW) using finite element method (FEM) simulations and analytical solutions. The FEM simulation results demonstrate excellent agreement with analytical expectations. The single-mode plasmon of the cylindrical single-layer GBW is found to have no cutoff, and is also extremely concentrated, significantly enhancing the electric field. We also apply our scheme to a cylindrical bilayer GBW comprising two interacting layers, and compare the simulation results with those of the single-layer GBW. Interestingly, the bilayer GBW only supports the fundamental mode as the zero-order mode is cutoff-free, thus achieving a single-mode operation. Moreover, the mode confinement and electromagnetic field are very stronger in bilayer GBW than in single-layer GBW, allowing for inducing stronger optical couplings in optical telecommunication applications such as light transmission through waveguides and optical switches.