A Reconfigurable Quantum Local Area Network Over Deployed Fiber

TL;DR

This paper demonstrates a reconfigurable quantum local area network over deployed fiber, utilizing flexible-grid bandwidth allocation to distribute entanglement across multiple nodes, enabling advanced quantum communication protocols.

Contribution

First implementation of flex-grid entanglement distribution in a deployed network connecting multiple campus buildings with GPS synchronization.

Findings

Successfully distributed entanglement over reconfigurable channels

Quantified link performance using log-negativity metric

Demonstrated remote state preparation on deployed fiber

Abstract

Practical quantum networking architectures are crucial for scaling the connection of quantum resources. Yet quantum network testbeds have thus far underutilized the full capabilities of modern lightwave communications, such as flexible-grid bandwidth allocation. In this work, we implement flex-grid entanglement distribution in a deployed network for the first time, connecting nodes in three distinct campus buildings time-synchronized via the Global Positioning System (GPS). We quantify the quality of the distributed polarization entanglement via log-negativity, which offers a generic metric of link performance in entangled bits per second. After demonstrating successful entanglement distribution for two allocations of our eight dynamically reconfigurable channels, we demonstrate remote state preparation -- the first realization on deployed fiber -- showcasing one possible quantum protocol enabled by the distributed entanglement network. Our results realize an advanced paradigm for managing entanglement resources in quantum networks of ever-increasing complexity and service demands.