Depending on the properties of graphene three methods can be used to achieve the modulation function including gate voltage modulation optical excitation and temperature modulation 25 Among them the g

There are three distinct methods for achieving modulation function in graphene, which are based on the unique properties of this material. These methods include gate voltage modulation, optical excitation, and temperature modulation. Gate voltage modulation and optical excitation can be used to alter the carrier concentration of graphene, which, in turn, modifies the real and imaginary parts of the refractive index, allowing for amplitude and phase modulation. Temperature modulation seeks to change the temperature of either the waveguide or substrate through heating of the graphene, resulting in modulation of the refractive index of the entire structure. Electro-optic and thermo-optic modulation are two such methods utilized for this purpose