Single-photon detection and cryogenic reconfigurability in Lithium Niobate nanophotonic circuits

TL;DR

This paper demonstrates integrated lithium niobate nanophotonic circuits with cryogenic reconfigurability and single-photon detection, enabling scalable quantum photonic devices with high-speed modulation and stable operation.

Contribution

It presents the first integration of reconfigurable LNOI circuits with superconducting nanowire detectors, showcasing static and dynamic control at cryogenic temperatures.

Findings

Successful integration of SNSPDs with LNOI waveguides.

Stable operation over 12 hours without bias drift.

High-speed modulation up to 1 GHz.

Abstract

Lithium-Niobate-On-Insulator (LNOI) is emerging as a promising platform for integrated quantum photonic technologies because of its high second-order nonlinearity and compact waveguide footprint. Importantly, LNOI allows for creating electro-optically reconfigurable circuits, which can be efficiently operated at cryogenic temperature. Their integration with superconducting nanowire single-photon detectors (SNSPDs) paves the way for realizing scalable photonic devices for active manipulation and detection of quantum states of light. Here we report the first demonstration of these two key components integrated in a low loss (0.2 dB/cm) LNOI waveguide network. As an experimental showcase of our technology, we demonstrate the combined operation of an electrically tunable Mach-Zehnder interferometer and two waveguide-integrated SNSPDs at its outputs. We show static reconfigurability of our system with a bias-drift-free operation over a time of 12 hours, as well as high-speed modulation at a frequency up to 1 GHz. Our results provide blueprints for implementing complex quantum photonic devices on the LNOI platform.