Microcomb-driven large-scale fully connected quantum network

TL;DR

This paper demonstrates a large-scale, fully connected quantum network using integrated microcombs and photonic chips, enabling secure communication among 200 users over 200 km with untrusted providers.

Contribution

It introduces a scalable architecture for fully connected quantum networks based on two-photon HOM interference and integrated microcombs, achieving high security and large user capacity.

Findings

Successfully connected 200 users over 200 km.

Achieved high-visibility HOM interference and MDI-QKD.

Demonstrated secure quantum communication with untrusted network providers.

Abstract

Fully connected quantum networks enable simultaneously connecting every user to every other user and are the most versatile and robust networking architecture. However, the scalability of such networks remains great challenge for practical applications. Here we construct a large-scale fully connected quantum network founded on two-photon Hong-Ou-Mandel (HOM) interference, where user-to-user security is guaranteed even with untrusted network provider. Using integrated soliton microcomb (SMC) and photonic encoding chips, we realize precise massive parallel frequency generation and locking, high-visibility HOM interferences and measurement-device-independent (MDI) quantum key distribution. The proposed architecture enables a 200-user fully connected quantum network over 200 kilometers with strict information-theoretic security via untrusted network provider. The implemented networking architecture paves the way for realizing large-scale fully connected MDI quantum networks across metropolitan and intercity regions.