Broadband dispersion engineered microresonator on-a-chip

TL;DR

This paper introduces a novel design and fabrication method for microresonators on a chip that enables precise dispersion control over a broad spectrum while maintaining high optical quality factors, advancing integrated nonlinear optics.

Contribution

The authors present a new fabrication technique for chip-integrated microresonators that achieves wide-bandwidth dispersion control with ultra-high Q factors, enabling improved optical frequency combs.

Findings

Achieved dispersion control over an octave of spectrum.

Maintained optical Q factors above 100 million.

Demonstrated potential for efficient nonlinear optical oscillators.

Abstract

Control of dispersion in fibre optical waveguides is of critical importance to optical fibre communications systems and more recently for continuum generation from the ultraviolet to the mid-infrared. The wavelength at which the group velocity dispersion crosses zero can be set by varying fibre core diameter or index step. Moreover, sophisticated methods to manipulate higher-order dispersion so as shape and even flatten dispersion over wide bandwidths are possible using multi-cladding fibre. Here we introduce design and fabrication techniques that allow analogous dispersion control in chip-integrated optical microresonators, and thereby demonstrate higher-order, wide-bandwidth dispersion control over an octave of spectrum. Importantly, the fabrication method we employ for dispersion control simultaneously permits optical Q factors above 100 million, which is critical for efficient operation of nonlinear optical oscillators. Dispersion control in high Q systems has taken on greater importance in recent years with increased interest in chip-integrable optical frequency combs.