Photonic Supercoupling in Silicon Topological Waveguides

TL;DR

This paper demonstrates photonic supercoupling in topological valley Hall waveguides, achieving high efficiency over large distances, which enhances on-chip photonic device integration and optical communication capabilities.

Contribution

It introduces the concept of photonic supercoupling in topological waveguides, enabling efficient energy transfer over distances much larger than traditional evanescent coupling.

Findings

Achieved 95% coupling efficiency at three-wavelength separation.

Demonstrated supercoupling through valley-conserved vortex flow.

Extended coupling distance significantly beyond conventional limits.

Abstract

Electromagnetic wave coupling between photonic systems relies on the evanescent field typically confined within a single wavelength. Extending evanescent coupling distance requires low refractive index contrast and perfect momentum matching for achieving a large coupling ratio. Here, we report the discovery of photonic supercoupling in a topological valley Hall pair of waveguides, showing a substantial improvement in coupling efficiency across multiple wavelengths. Experimentally, we realize ultra-high coupling ratios between waveguides through valley-conserved vortex flow of electromagnetic energy, attaining 95% coupling efficiency for separations of up to three wavelengths. This demonstration of photonic supercoupling in topological systems significantly extends the coupling distance between on-chip waveguides and components, paving the path for the development of supercoupled photonic integrated devices, optical sensing, and telecommunications.