Free spectral range electrical tuning of a high quality on-chip microcavity

TL;DR

This paper presents an on-chip microcavity with electrically tunable resonances across a full free spectral range, enabling highly reconfigurable photonic circuits with low power consumption and broad application potential.

Contribution

The authors develop a high quality microcavity with full FSR electrical tuning using nanoelectronic actuation and optomechanical interactions, overcoming previous size limitations.

Findings

Achieved resonance tuning across a full free spectral range.

Demonstrated reconfigurable photonic network with microcavity.

Low voltage and sub-nanowatt power consumption.

Abstract

Reconfigurable photonic circuits have applications ranging from next-generation computer architectures to quantum networks, coherent radar and optical metamaterials. However, complete reconfigurability is only currently practical on millimetre-scale device footprints. Here, we overcome this barrier by developing an on-chip high quality microcavity with resonances that can be electrically tuned across a full free spectral range (FSR). FSR tuning allows resonance with any source or emitter, or between any number of networked microcavities. We achieve it by integrating nanoelectronic actuation with strong optomechanical interactions that create a highly strain-dependent effective refractive index. This allows low voltages and sub-nanowatt power consumption. We demonstrate a basic reconfigurable photonic network, bringing the microcavity into resonance with an arbitrary mode of a microtoroidal optical cavity across a telecommunications fibre link. Our results have applications beyond photonic circuits, including widely tuneable integrated lasers, reconfigurable optical filters for telecommunications and astronomy, and on-chip sensor networks.