▎ 摘　　要

We investigate the propagation length of plasmon waves in a graphene film sandwiched by two identical anisotropic dielectrics. The plasmon losses in graphene can be controlled by varying the external carrier doping. In the proposed system, a doped graphene sheet behaves as a thin metal film to support the long range surface plasmons. Here, we consider artificial crystal such as photonic crystal to increase the anisotropy of the dielectrics, which has stronger anisotropy than naturally available optical dielectrics. It is observed that the propagation length, nanoscale mode confinement and penetration depth of surface plasmons increase when the surrounding dielectrics are birefringent crystal with a properly oriented optical axis.