Fig. 1. Structural diagram of graphene photoelectric modulator. (a) Three dimensional profile of graphene/dielectric/graphene branched structure; (b) schematic of applied voltage on graphene

Fig. 2. Schematic diagram of preparation process of graphene photoelectric modulator. (a) Silicon dioxide substrate; (b) rectangular branched waveguide structure; (c) graphene encapsulated branched structure; (d) graphene photoelectric modulator

Fig. 3. Graphene/dielectric/graphene branched structure

Fig. 4. Distributions of time average value of electromagnetic field energy density in main waveguide when (a) d1=d2=315 nm and (b) d1=d2=560 nm; relationship between optical field energy of input end and output end in main waveguide and chemical potential of graphene when (c) d1=d2=315 nm and (d) d1=d2=560 nm

Fig. 5. Relationship between electromagnetic field energy in main waveguide and branch length. (a) Dielectric material is SiO2; (b) dielectric material is Si

Fig. 6. Relationship between electromagnetic field energy in main waveguide and incident wavelength. (a) d1=d2=315 nm; (b) d1=d2=560 nm

Fig. 7. Relationship between electromagnetic field energy in waveguide and incident wavelength under different chemical potentials of graphene