▎ 摘　　要

In this paper, a new electro-optical switch modulator based on the surface plasmon polaritons of graphene is proposed. An air-graphene-substrate-dielectric structure is adopted in the modulator. In this structure, the graphene is considered as a film of metal whose thickness tends to be infinitesimal. By changing the external voltage, the boundary conditions can be changed to decide whether the surface plasmon polariton waves can be excited in mid-infrared band. Because of this effect, the structure can be used as an electro-optical switch modulator, whose modulation depth is about 100% in theory. Finally, the 3 dB bandwidth (similar to 34 GHz) and the energy loss (36.47 fJ/bit) of the electro-optical switch modulator are given, whose low energy loss is very suitable for engineering applications.