北大团队Nature发文：建成全球首个大规模集成光量子通信芯片网络

Core Insights - A significant technological advancement in quantum communication has been achieved by a collaborative team from Peking University's School of Physics and School of Electronics, resulting in the development of a fully integrated quantum key distribution (QKD) network named "Weiming Quantum Network" [1] Group 1: Technological Achievements - The research team successfully created an integrated quantum key sending chip and an optical microcavity frequency comb light source chip, enabling the world's first large-scale QKD network based on integrated optical quantum chips [1] - The network demonstrated parallel communication among 20 chip user nodes, achieving a communication distance of 370 kilometers, thus breaking the distance limit of direct transmission without relays [1] - The system reached a "networking capability" of 3700 kilometers, calculated as the product of the number of client nodes and communication distance, validating the feasibility of large-scale, long-distance quantum secure communication through integrated photonic technology [1] Group 2: Hardware Architecture - The research utilized a hybrid material system of indium phosphide (InP) and silicon nitride (SiN) for hardware architecture, with a central server node deploying a silicon nitride optical microcavity frequency comb as a seed light source [2] - The system produced a coherent dark pulse frequency comb with an ultra-low noise linewidth of only 40 Hz, replacing traditional complex desktop laser systems [2] - The user end incorporated 20 fully integrated indium phosphide quantum chips, achieving a device yield of 97.5% and maintaining high consistency under wafer-level manufacturing processes [2] Group 3: Protocol and Performance - The research employed a twin-field quantum key distribution (TF-QKD) protocol combined with wavelength division multiplexing technology, effectively addressing signal interference and phase tracking challenges in multi-user networks [2] - Experimental results indicated that the system could maintain low error rates even over long-distance fiber transmission of 370 kilometers, with a data rate surpassing the theoretical limits of linearity [2] - This technological approach offers a new chip-level solution for reducing the cost of quantum communication devices and enhancing network scalability [2]