▎ 摘　　要

In this study, a three-layered system consisting of a Kerr-type nonlinear medium confined between two semi-infinite linear media is considered. The nonlinear medium is a parallel-plate graphene waveguide with a thickness of d. Analytical expressions for dispersion relation and the field profiles in terms of Jacobi elliptic functions are performed and solved numerically. Plasmonic properties such as the effective mode index (n(eff)), localization length (delta) are studied. It is found that n(eff) and delta of the system can be tuned by chemical potential of graphene, arising from its tunable optical conductivity. Localization of transverse electric (TE) surface waves increases with increasing the medium nonlinearity, providing deep-subwavelength confinement. Moreover, increasing d from 1 to 130 nm enhances the mode confinement. We also apply our scheme to a bilayer graphene (BLG) waveguide, allowing for predicting the existence of TE modes. Our results show that the TE modes in BLG are more pronounced than those in single-layer graphene. Therefore, the BLG structure is found to be promising in the fabrication of optical devices with TE plasmons.