Realizing an entanglement-based multi-user quantum network with integrated photonics

TL;DR

This paper demonstrates a scalable multi-user quantum network using integrated silicon nitride photonics, enabling secure quantum communication among four users with high interference visibility and potential for large-scale deployment.

Contribution

It introduces an energy-time entanglement-based dense wavelength division multiplexed quantum network using integrated silicon nitride micro-ring resonators, achieving simultaneous multi-user connectivity.

Findings

Six photon pairs form a fully connected four-user network.

Quantum interference visibilities exceed classical limits.

All user pairs successfully perform quantum key distribution.

Abstract

Quantum network facilitates the secure transmission of information between different users. Establishing communication links among multiple users in a scalable and efficient way is important for realizing a large-scale quantum network. Here we develop an energy-time entanglement-based dense wavelength division multiplexed network based on an integrated silicon nitride micro-ring resonator, which offers a wide frequency span (covering at least the entire C-band) and narrow bandwidth modes (~ 650MHz). Six pairs of photons are selected to form a fully and simultaneously connected four-user quantum network. The observed quantum interference visibilities are well above the classical limits among all users. Each pair of users perform the BBM92 protocol for quantum key distribution. Our results pave the way for realizing large-scale quantum networks with integrated photonic architecture.