Engineered Octave Frequency Comb in Integrated Chalcogenide Dual-ring Microresonators

TL;DR

This paper introduces a novel dual-ring microresonator design that enables flexible dispersion engineering, leading to the generation of broadband, flat Kerr frequency combs spanning from telecom to mid-infrared wavelengths.

Contribution

It proposes a new concentric dual-ring microresonator structure for advanced dispersion control, enabling the creation of octave-spanning, flat Kerr combs with improved spectral properties.

Findings

Achieved an octave-spanning Kerr comb with -40 dB flatness over 1265 nm bandwidth.

Demonstrated flexible dispersion engineering via microresonator geometry and gap control.

Numerically validated broadband comb generation from telecom to MIR bands.

Abstract

Broadband Kerr combs with a flat comb spectral profile are expected in a number of applications, such as high-capacity optical communication. Here, we propose novel concentric dual-ring microresonators (DRMs) for advanced dispersion engineering to tailor the comb spectral profile. The dispersion can be flexibly engineered not only by the cross-section of the DRMs, but also by the gap between concentric dual-ring microresonators, which provides a new path to geometrically control the spectral profile of the soliton Kerr combs. An octave-spanning dissipative Kerr soliton comb with superior spectral flatness has been achieved numerically, covering from the telecommunication band to the mid-infrared (MIR) band region with a -40 dB bandwidth of 1265 nm (99.82 THz). Our results are promising to fully understand the nonlinear dynamics in hybrid modes in DRMs, which helps control broadband comb formation.