Microcomb-driven large-scale fully connected quantum network

Fully connected quantum networks enable simultaneous connection of every user to every other user and are a highly versatile and robust networking architecture. However, the scalability of such networks remains a 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 an untrusted network provider. Using integrated soliton microcomb (SMC) and photonic encoding chips, we realize precise, massively parallel frequency generation and locking, high-visibility HOM interference and measurement-device-independent (MDI) quantum key distribution. The proposed architecture enables a fully connected quantum network over 200 kilometers with strict information-theoretic security via an untrusted network provider. The implemented networking architecture paves the way for large-scale fully connected MDI quantum networks across metropolitan and intercity regions. Fully connected quantum networks could enable secure communication between all users, but scalable operation with untrusted providers remains challenging. Here, the authors demonstrate a microcomb-driven measurement-device-independent quantum network using integrated photonics over 200-km fibre.

Source: https://www.nature.com/articles/s41467-026-75658-6. 8sync News only summarizes and links out; content copyright belongs to the authors and original sources.