A quantum frequency conversion hub interfacing with DWDM networks

TL;DR

This paper presents a quantum frequency conversion hub that enables interfacing local quantum devices with telecom DWDM networks, demonstrating wide tunability and multi-channel distribution of quantum information.

Contribution

It introduces a novel quantum network hub using dispersion sweet spots in lithium niobate waveguides for efficient, channel-selective frequency conversion compatible with telecom networks.

Findings

Achieved a 2 THz pump tuning range for QFC.

Successfully distributed polarization-encoded single photons into 16 channels.

Maintained quantum information fidelity across multiple channels.

Abstract

Interconnecting heterogeneous quantum systems is an important step toward realizing the quantum internet. We propose a quantum network hub that interfaces local quantum devices with dense wavelength-division multiplexing (DWDM) networks in the telecom band via quantum frequency conversion (QFC) with frequency-channel selectivity. We show that standard periodically poled lithium niobate waveguides used for QFC exhibit a dispersion sweet spot, for example around the 780 nm band, enabling wide tunability of the pump wavelength while maintaining phase matching. Experimentally, we demonstrate the network hub by implementing a channel-selective and polarization-insensitive QFC from 780 nm to telecom wavelengths around 1540 nm. We achieve a pump tuning range of 2 THz and successfully distribute polarization-encoded single photons into 16 frequency channels on the ITU-T DWDM grid with 25 GHz channel spacing, while preserving the quantum information. These results position the QFC-based hub as a versatile backbone for connecting a wide range of quantum devices, spanning both photonic and matter-based systems, across frequency-multiplexed telecom networks.