Abstract

Multimode interference (MMI) is a fundamental physical principle that plays a crucial role in modern communication technologies for wave splitting, filtering, switching and multiplexing. Typically, the generation of multimodes is highly dependent on the waveguide’s cross-section, particularly its width, by which the mode profiles and the interference patterns can be severely affected, leading to unstable MMI performance. Here, we realize width-independent and robust MMI waveguides based on multilayer graphene lattices. By properly modulating the boundary potential, this Dirac-type material supports anomalous bulk states with uniform wavefunctions independent of the sample size. The bulk states in a waveguide formed by multiple layers of graphene ribbons exhibit width-independent MMI. Standard 2×2 MMI waveguides are constructed using bilayer photonic and phononic crystals with graphene lattices, and experimental measurements show frequency-tunable splitting and robustness to geometric perturbations. Multiple interconnects with stepped widths further demonstrate stable MMI with high coupling efficiency.

Abstract

Multimode interference (MMI) is a fundamental physical principle that plays a crucial role in modern communication technologies for wave splitting, filtering, switching and multiplexing. Typically, the generation of multimodes is highly dependent on the waveguide’s cross-section, particularly its width, by which the mode profiles and the interference patterns can be severely affected, leading to unstable MMI performance. Here, we realize width-independent and robust MMI waveguides based on multilayer graphene lattices. By properly modulating the boundary potential, this Dirac-type material supports anomalous bulk states with uniform wavefunctions independent of the sample size. The bulk states in a waveguide formed by multiple layers of graphene ribbons exhibit width-independent MMI. Standard 2×2 MMI waveguides are constructed using bilayer photonic and phononic crystals with graphene lattices, and experimental measurements show frequency-tunable splitting and robustness to geometric perturbations. Multiple interconnects with stepped widths further demonstrate stable MMI with high coupling efficiency.

Abstract

Multimode interference (MMI) is a fundamental physical principle that plays a crucial role in modern communication technologies for wave splitting, filtering, switching and multiplexing. Typically, the generation of multimodes is highly dependent on the waveguide’s cross-section, particularly its width, by which the mode profiles and the interference patterns can be severely affected, leading to unstable MMI performance. Here, we realize width-independent and robust MMI waveguides based on multilayer graphene lattices. By properly modulating the boundary potential, this Dirac-type material supports anomalous bulk states with uniform wavefunctions independent of the sample size. The bulk states in a waveguide formed by multiple layers of graphene ribbons exhibit width-independent MMI. Standard 2×2 MMI waveguides are constructed using bilayer photonic and phononic crystals with graphene lattices, and experimental measurements show frequency-tunable splitting and robustness to geometric perturbations. Multiple interconnects with stepped widths further demonstrate stable MMI with high coupling efficiency.

Abstract

Multimode interference (MMI) is a fundamental physical principle that plays a crucial role in modern communication technologies for wave splitting, filtering, switching and multiplexing. Typically, the generation of multimodes is highly dependent on the waveguide’s cross-section, particularly its width, by which the mode profiles and the interference patterns can be severely affected, leading to unstable MMI performance. Here, we realize width-independent and robust MMI waveguides based on multilayer graphene lattices. By properly modulating the boundary potential, this Dirac-type material supports anomalous bulk states with uniform wavefunctions independent of the sample size. The bulk states in a waveguide formed by multiple layers of graphene ribbons exhibit width-independent MMI. Standard 2×2 MMI waveguides are constructed using bilayer photonic and phononic crystals with graphene lattices, and experimental measurements show frequency-tunable splitting and robustness to geometric perturbations. Multiple interconnects with stepped widths further demonstrate stable MMI with high coupling efficiency.