Abstract
Abstract Building scalable and secure quantum networks requires advanced quantum key distribution (QKD) protocols
that support multi-user connectivity. Continuous-variable (CV) measurement-device-independent
(MDI) QKD, which eliminates all detector side-channel attacks, is a promising candidate for creating
various quantum network topologies—such as quantum access networks and star-type topologies—using
standard technology and providing high secure key rates. However, its security has so far only been
experimentally demonstrated in asymptotic regimes with limited secret key rates and complex experimental
setups, limiting its practical applications. Here, we report the first experimental validation of a CV
MDI-QKD system, achieving a secure key rate of 2.6 Mbit/s against collective attacks in the finite-size
regime over a 10 km fiber link. This is achieved using a new system design, incorporating a locally
generated local oscillator, a new relay structure, a real-time phase locking system, and a well-designed
digital-signal-processing pipeline for quantum state preparation and CV Bell measurements at a symbol
rate of 20 MBaud. Our results set a new benchmark for secure key exchange and open the possibility
of establishing high-performance CV MDI-QKD networks, paving the way toward a scalable quantum
network.
Published Version
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