Disorder effects on the coupling strength of coupled photonic crystal slab cavities

TL;DR

This study investigates how fabrication disorder impacts the coupling strength of coupled photonic crystal slab cavities using 3D electromagnetic simulations, revealing that disorder causes linear fluctuations in photon hopping and setting bounds for manufacturing imperfections.

Contribution

It provides a detailed analysis of disorder effects on coupling strength in photonic crystal cavities, including quantitative bounds for fabrication imperfections.

Findings

Photon hopping fluctuations increase linearly with disorder amplitude.

Disorder affects photon hopping more than eigenfrequency fluctuations.

Upper bounds on fabrication imperfections are established.

Abstract

We study the effects of disorder on the coupling strength of coupled photonic crystal slab cavities by considering fully-3D electromagnetic calculations. Specifically, we investigate two coupled L3 cavities at 30{\deg} and 60{\deg} configurations, where the coupling strength J (or photon hopping) is extracted from the simulations in the presence of disorder. We found that the relative fluctuations of the photon hopping are more sensitive to disorder effects than the corresponding fluctuations in the eigenfrequencies of the coupled cavities. Furthermore, for the typical range of disorder in state-of-the-art devices, the J fluctuations are found to increase linearly as a function of the disorder amplitude. This allows to set upper bounds to the amplitude of fabrication imperfections, for which the coupling predicted by design can still be expected, on average, in a fabricated device.