Design of graphene-based polarization-insensitive optical modulator

By exploiting the electroabsorption effect of graphene, we present a graphene-based polarization-insensitive optical modulator. The waveguide structure consists of a silica substrate, high-index silicon strip waveguide, Si3N4 dielectric spacer, two graphene layers, and two metal electrodes. The modulator performance is comprehensively studied in terms of attenuation, insertion loss, modulation depth, and bandwidth. We achieve broadband >16 dB attenuation graphene-based optical modulator over a 35 nm wavelength range (covering C band) with an imbalance of no >1 dB and insertion loss of <2 dB for transverse magnetic and transverse electric polarized modes. Moreover, the electrical properties such as energy per bit consumption (Ebit) are also studied.