An Integrated Photon-Pair Source with Monolithic Piezoelectric Frequency Tunability

TL;DR

This paper presents a monolithically integrated photon-pair source with piezoelectric frequency tuning, enabling fast and wide-bandwidth frequency control suitable for quantum communication and memory interfacing.

Contribution

It introduces a silicon nitride microresonator with integrated aluminum nitride for rapid, cryogenic-compatible frequency tuning of entangled photon pairs, surpassing thermal tuning limitations.

Findings

Achieved fast frequency locking with high bandwidth.

Demonstrated cryogenic-compatible piezoelectric tuning.

Enabled stable entangled photon-pair generation at telecom wavelengths.

Abstract

This work demonstrates the capabilities of an entangled photon-pair source at telecom wavelengths, based on a photonic integrated Si$_3$N$_4$ microresonator with monolithically integrated piezoelectric frequency tuning. Previously, frequency tuning of photon-pairs generated by microresonators has only been demonstrated using thermal control, however these have limited actuation bandwidth, and are not compatible with cryogenic environments. Here, the frequency-tunable photon-pair generation capabilities of a Si$_3$N$_4$ microresonator with a monolithically integrated aluminium nitride layer are shown. Fast-frequency locking of the microresonator to an external laser is demonstrated, with a resulting locking bandwidth orders of magnitude larger than reported previously using thermal locking. These abilities will have direct application in future schemes which interface such sources with quantum memories based on e.g. trapped-ion or rare-earth ion schemes.