Fig. 1. Permittivity of graphene versus chemical potential

Fig. 2. Structural diagram of composite waveguide modulator based on graphene. (a) 2D cross section; (b) 3D model

Fig. 3. Propagation loss of composite waveguide and chemical potential of graphene versus bias voltage

Fig. 4. (a) Effect of slit width on modulation efficiency; (b) effect of Si waveguide width on modulation efficiency

Fig. 5. Structural diagram and coupling efficiency of tapered coupler

Fig. 6. (a)(b) Optical energy transmission distribution of modulator and (c)(d) optical mode distribution of output waveguide under different chemical potentials of graphene