In-resonator variation of waveguide cross-sections for dispersion control of aluminum nitride micro-rings

TL;DR

This paper introduces a novel dispersion control method for aluminum nitride micro-ring resonators by combining waveguides of different cross sections, enabling near-zero dispersion and improved mode suppression.

Contribution

It presents a new technique of combining waveguide cross sections within micro-ring resonators to precisely control dispersion and suppress mode coupling.

Findings

Achieved near-zero total dispersion in micro-ring resonators.

Effectively suppressed multimode mode coupling.

Enhanced flexibility in dispersion engineering for microcomb applications.

Abstract

We propose and demonstrate a dispersion control technique by combination of different waveguide cross sections in an aluminum nitride micro-ring resonator. Narrow and wide waveguides with normal and anomalous dispersion, respectively, are linked with tapering waveguides and enclosed in a ring resonator to produce a total dispersion near zero. The mode-coupling in multimoded waveguides is also effectively suppressed. This technique provides new degrees of freedom and enhanced flexibility in engineering the dispersion of microcomb resonators.