Chiral transport in Compact topological waveguide arrays

TL;DR

This paper demonstrates a topologically protected chiral transport in a compact waveguide array, significantly reducing device size by leveraging non-Hermitian physics and exceptional points.

Contribution

Introducing topological protection in encircling exceptional points systems to enable smaller, efficient chiral transport devices in photonics.

Findings

Achieved chiral transport in a 75 μm long waveguide array.

Fused topology with non-Hermitian physics for device miniaturization.

Demonstrated potential for highly-integrated photonic chips.

Abstract

Waveguide arrays have a wide range of applications, including optical communication, topological systems, and quantum computing. Chiral transport has broad prospects in optical computing, optical switching, optical isolation, and polarization control. However, the lengths of chiral transmission devices in waveguide arrays are typically very long due to adiabatic limit. We introduce topological protection in encircling exceptional points systems, enabling the larger gap size between the bulk states and topological edge states (TESs). Thus, the restriction from adiabatic limit on the rapid evolution of TESs is eased, thereby significantly reducing the device size. We experimentally demonstrate that the chiral transport has been achieved in a topological waveguide array that is only 75 {\mu}m long. Our research fuses the topology with non-Hermitian physics to develop highly-integrated photonic chips for further advance of nano-photonics.