Fast dispersion tailoring of multimode photonic crystal resonators

TL;DR

This paper presents a rapid numerical method for designing multimode photonic crystal resonators, enabling efficient optimization of their spectral properties for applications like nano-combs and mode-locked lasers.

Contribution

A simple one-dimensional model is introduced that accurately reproduces the optical response of complex photonic crystal structures, significantly speeding up the design process.

Findings

The model accurately predicts the spectral response across the entire range.

Optimization of the width profile flattens the dispersion, improving device performance.

The approach can be extended to complex geometries with multiple parameters.

Abstract

We introduce a numerical procedure which permits to drastically accelerate the design of multimode photonic crystal resonators. Specifically, we demonstrate that the optical response of an important class of such nanoscale structures is reproduced accurately by a simple, one-dimensional model, within the entire spectral range of interest. This model can describe a variety of tapered photonic crystal structures. Orders of magnitude faster to solve, our approach can be used to optimize certain properties of the nanoscale cavity. Here we consider the case of a nanobeam cavity, where the confinement results from the modulation of its width. The profile of the width is optimized, in order to flatten the resonator dispersion profile (so that all modes are equally spaced in frequency). This result is particularly relevant for miniaturizing parametric generators of non-classical light, optical nano-combs and mode-locked laser sources. Our method can be easily extended to complex geometries, described by multiple parameters.