Efficient and compact graphene-based optical modulator using dual-annular elliptical silicon waveguide

Abstract

A high-performance optical modulator based on three graphene (Gr) layers integrated with a dual elliptic-shaped silicon waveguide is proposed and investigated. The device is optimized for transverse electric mode operation, where the elliptic geometry is engineered to enhance modulation efficiency and compactness. The key performance indicators-including propagation loss (Lp), modulation depth (MD), bandwidth, energy consumption, and device footprint-are comprehensively analyzed through numerical simulations employing the finite element method. Simulation results reveal that the proposed modulator achieves a MD of 0.745 dB<i>μ</i>m^-1, a compact cross-sectional area of 1.08<i>μ</i>m², and a low Lp of 0.045 dB<i>μ</i>m^-1at the telecommunication wavelength of 1550 nm. Further geometry optimization demonstrates enhanced modulation capability and reduced energy consumption. These results highlight the potential of the proposed structure as an energy-efficient and scalable candidate for future photonic integrated circuits and for advancing active nanophotonic devices incorporating two-dimensional materials.