Multimode Single-Ring Photonic Molecule

TL;DR

This paper introduces a novel method using a single multimode optical ring resonator to create scalable and flexible photonic molecules, enabling complex interactions and phenomena in integrated photonics.

Contribution

The authors demonstrate a new approach that employs multiple waveguide transverse modes in one resonator for arbitrary inter-mode coupling and precise control of photonic interactions.

Findings

Achieved arbitrary inter-mode coupling via transmissive mode converters.

Enabled precise tuning of resonance splitting and intrinsic losses.

Facilitated the generation of selective bright-dark mode pairs.

Abstract

Photonic molecules can mimic interactions of atomic energy levels, offering new ways to manipulate cavity eigenstates. Current methods using evanescent coupling of multiple cavities face challenges in scalability, flexibility, and coupling control, especially for complex systems. Here we introduce a new method that uses a single multimode optical ring resonator to create photonic molecules. Our design uses multiple waveguide transverse modes in one resonator, providing flexibility to engineer complex interactions without typical coupling constraints. We demonstrate arbitrary inter-mode coupling through transmissive mode converters, allowing precise tuning of resonance splitting and intrinsic losses. This approach enables selective bright-dark mode pair generation and the exploration of novel photonic phenomena such as exceptional points. This multimode photonic molecule overcomes traditional limitations and offers new possibilities for integrated photonic circuits, optical processing, and studies in non-Hermitian and nonlinear photonics.