High-Speed Efficient On-Chip Electro-Optic Modulator Based on Midinfrared Hyperbolic Metamaterials

Integrated modulators are key components for on-chip optical communication and information processing, which have become leading technologies in the current information-growth era. Hence, high-speed, efficient, and compact integrated modulators are in high demand. However, the current integrated midinfrared modulators meet these requirements with difficulty. Here, we present a high-speed and efficient on-chip electro-optic modulator based on midinfrared hyperbolic metamaterials using stacking of graphene and hexagonal boron nitride. The length of the modulation region is only 60 nm, which is integrated on a plasmonic waveguide composed of hyperbolic metamaterials. The maximum modulation depth is up to 30 dB, and the 3-dB modulation speed can reach up to 50 GHz, which is supported by a detailed study of a small-signal frequency-response model. Our work provides an alternative scheme for the design of modulators with the requirements of sub-100-nm integration and 50-GHz modulation speed or even beyond, which can be directly implemented into a two-dimensional-materials-based photonic integrated circuits platform.