High-Speed Optical Phase Modulator Based on Graphene-Silicon Waveguide

A high-speed optical phase modulator based on graphene-silicon waveguide (GSW) is presented. Two graphene flakes, sandwiched by insulating dielectric spacers, are embedded in a silicon waveguide to enhance the interaction between the graphene and light. By applying a bias on the graphene flakes, the refractive index variation of TE mode in the waveguide shows a large quasi-linear dynamic range, which is ideal for achieving optical phase modulation. Based on this structure, a π phase shift can be achieved by a 75.6 μm-long GSW. Calculations show that the 3 dB modulation bandwidth of the optical phase modulator can be as high as 119.5 GHz with a low consumption of 0.452 pJ/bit.