▎ 摘　　要

A symmetric graphene dielectric hybrid plasmonic waveguide (SGDHPW) has proposed with ultra-deep subwavelength confinement in the mid-infrared spectrum. The SGDHPW structure is include of two symmetric SiO2 semi-elliptical cylinders with graphene-coated embedded on each side of an Al2O3 strip with a thickness t and width W, which are surrounded by MgF2 material. We employed the finite element computational technique to investigation of the mode characteristics of graphene surface plasmon polariton (GSPP) mode. In the proposed waveguide, the GSPP mode can be attained a figure of merit over 1000 and a normalized mode area of similar to 10(-6) to similar to 10(-5) by setting the dimensions of the waveguide geometry and the graphene Fermi energy. Furthermore, as to the modal features, crosstalk investigation demonstrates that the proposed structures display very small crosstalk, even at a segregation area of 69 nm. Owing to the derived remarkable results, the proposed scheme has valuable applications in optical integrated circuits and other absorbing nano-photonic devices in the mid-infrared spectrum.