Photonic topological valley-locked waveguides

TL;DR

This paper introduces topological valley-locked waveguides with tunable mode widths using a photonic crystal with a Dirac point, enabling enhanced control and new applications in integrated photonics.

Contribution

The work demonstrates a novel design of topological valley-locked waveguides with adjustable mode widths, combining experimental validation with potential for diverse photonic applications.

Findings

Successfully designed and experimentally demonstrated tunable mode width waveguides.

Enabled new applications like topological channel intersections and energy concentrators.

Provided a platform for practical topological lasing and high-capacity energy transport.

Abstract

Topological valley kink states have become a significant research frontier with considerable intriguing applications such as robust on-chip communications and topological lasers. Unlike guided modes with adjustable widths in most conventional waveguides, the valley kink states are usually highly confined around the domain walls and thus lack the mode width degree of freedom (DOF), posing a serious limitation to potential device applications. Here, by adding a photonic crystal (PhC) featuring a Dirac point between two valley PhCs with opposite valley-Chern numbers, we design and experimentally demonstrate topological valley-locked waveguides (TVLWs) with tunable mode widths. The photoinc TVLWs could find unique applications, such as high-energy-capacity topological channel intersections, valley-locked energy concentrators, and topological cavities with designable confinement, as verified numerically and experimentally. The TVLWs with width DOF could be beneficial to interface with the exsisting photonic waveguides and devices, and serve as a novel platform for practical use of topological lasing, field enhancement, on-chip communicaitons, and high-capacity energy transport.