Design and Simulation of High-Efficiency Broadband Terahertz Graphene Composite Waveguide Modulators

Terahertz (THz) modulators are crucial components in terahertz high-speed communications and interconnections. In this article, we demonstrate a high-efficiency broadband terahertz graphene composite modulator. The modulator is composed of a double-layer graphene integrated Si slot waveguide on a SiO
₂
substrate, which significantly enhances in-plane polarization matching and interaction between graphene and the THz wave. The transmission characteristics of the guided THz wave can be flexibly tuned by controlling the chemical potential of graphene. The modulator achieves excellent amplitude modulation performance, with a modulation depth of 99%, insertion loss of 0.0051 dB/μm, modulation length of 300 μm, modulation bandwidth of 19.59 GHz, and energy consumption of 384.5 pJ/bit at 1 THz. This work offers a potential solution for designing high-performance graphene-based THz modulators, with promising applications in future high-speed THz telecommunication and interconnect systems.