Ultra-high-Q tunable whispering-gallery-mode microresonator

TL;DR

This paper demonstrates the fabrication of ultra-high-Q, tunable whispering-gallery-mode microresonators from standard optical fibers, overcoming previous limitations in resonance frequency control for advanced photonic applications.

Contribution

It introduces a simple, customizable design of bottle microresonators with ultra-high quality factors and full tunability, fabricated from standard optical fibers.

Findings

Achieved an ultra-high quality factor of 360 million.

Demonstrated full resonance tunability.

Enabled near lossless fiber coupling.

Abstract

Typical microresonators exhibit a large frequency spacing between resonances and a limited tunability. This impedes their use in a large class of applications which require a resonance of the microcavity to coincide with a predetermined frequency. Here, we experimentally overcome this limitation with highly prolate-shaped whispering-gallery-mode "bottle microresonators" fabricated from standard optical glass fibers. Our resonators combine an ultra-high quality factor of 360 million, a small mode volume, and near lossless fibre coupling, characteristic of whispering-gallery-mode resonators, with a simple and customizable mode structure enabling full tunability.