▎ 摘　　要

The rapid growth of THz communication systems needed a high data transfer rate in the broadband communication range. Increasing the amount of modulation depth increases the amount of transmission and, as a result, increases the transmitted data. In this paper, a broadband optical modulator based on rib-type silicon waveguides, including graphene and h-BN layers, is designed. In this proposed structure, Hexagonal Boron Nitride (h-BN) layers are embedded between graphene layers. This structure contains a rib-type Si waveguide and operates for the broadband wavelength from 1300 nm to 1800 nm. The maximum modulation depth is 2.23 dB/ mu m with 2.23 dB/mu m loss at 1800 nm. We achieved a high figure of merit as high as 1.3. The modulation depth at 1550 nm is 1.13 dB/mu m with 1.1 dB/mu m loss. The proposed modulator has a 669 GHz modulation bandwidth.