Flexible entanglement-distribution network with an AlGaAs chip for secure communications

TL;DR

This paper demonstrates a scalable, flexible quantum communication network using an on-chip entangled photon source combined with wavelength division multiplexing, enabling secure communication among multiple users over fiber links.

Contribution

It introduces a reconfigurable, resource-optimized quantum network architecture integrating an on-chip entangled photon source with industry-grade multiplexing techniques.

Findings

Successful entanglement distribution to 8 users

High secret key rates achieved across multiple channels

Flexible bandwidth allocation demonstrated

Abstract

Quantum communication networks enable applications ranging from highly secure communication to clock synchronization and distributed quantum computing. Miniaturized, flexible, and cost-efficient resources will be key elements for ensuring the scalability of such networks as they progress towards large-scale deployed infrastructures. Here, we bring these elements together by combining an on-chip, telecom-wavelength, broadband entangled photon source with industry-grade flexible-grid wavelength division multiplexing techniques, to demonstrate reconfigurable entanglement distribution between up to 8 users in a resource-optimized quantum network topology. As a benchmark application we use quantum key distribution, and show low error and high secret key generation rates across several frequency channels, over both symmetric and asymmetric metropolitan-distance optical fibered links and including finite-size effects. By adapting the bandwidth allocation to specific network constraints, we also illustrate the flexible networking capability of our configuration. Together with the potential of our semiconductor source for distributing secret keys over a 60 nm bandwidth with commercial multiplexing technology, these results offer a promising route to the deployment of scalable quantum network architectures.