Photonic molecules formed by coupled hybrid resonators

TL;DR

This paper presents a method for creating and tuning photonic molecules by coupling free-standing and on-chip whispering-gallery-mode microresonators with different geometries, enabling spectral control through thermal tuning and distance adjustment.

Contribution

It introduces a novel approach to spectral tuning and coupling of hybrid resonators, combining free-standing and on-chip microresonators with different materials and geometries.

Findings

Successful thermal tuning of resonance modes.

Observation of mode splitting due to evanescent coupling.

Dependence of spectral splitting on resonator distance.

Abstract

We describe a method that enables free-standing whispering-gallery-mode microresonators, and report spectral tuning of photonic molecules formed by coupled free and on-chip resonators with different geometries and materials. We study direct coupling via evanescent fields of free silica microtoroids and microspheres with on-chip polymer coated silica microtoroids. We demonstrate thermal tuning of resonance modes to achieve maximal spectral overlap, mode splitting induced by direct coupling, and the effects of distance between the resonators on the splitting spectra.