Band splitting and Modal Dispersion induced by Symmetry braking in Coupled-Resonator Slow-Light Waveguide Structures

TL;DR

This paper investigates how symmetry breaking in coupled microdisk resonator waveguides causes mode splitting and affects dispersion, impacting the bandwidth and performance of slow-light optical communication devices.

Contribution

It provides a group theoretical analysis of symmetry-induced mode splitting in coupled-resonator waveguides, revealing effects on dispersion and bandwidth limitations.

Findings

Degeneracy of CW and CCW modes is lifted, creating two transmission bands.

Symmetry-based dispersion can limit the usable bandwidth.

Impact on CROW performance for optical communications is analyzed.

Abstract

We study the dispersion relations in slow-light waveguide structures consisting of coupled microdisk resonators. A group theoretical analysis of the symmetry properties of the propagating modes reveals an interesting phenomenon: The degeneracy of the CW and CCW rotating modes is removed, giving rise to two distinct transmission bands. This effect induces symmetry-based dispersion which may limit usable bandwidth of such structures. The properties of this band splitting and its impact on CROW performance for optical communications are studied in detail.