Chinese scientists have achieved a quantum communication breakthrough by establishing the world’s largest quantum key distribution (QKD) network spanning 3,700 kilometers. The research team, led by Professor Wang Jianwei from Peking University’s School of Physics and Academician Gong Qihuang of the Chinese Academy of Sciences, has successfully deployed this advanced network utilizing fully integrated photonic quantum chips.
This pioneering infrastructure supports simultaneous secure communication for 20 users, representing a significant advancement in both network scale and geographical coverage. The system employs twin-field QKD technology, which utilizes quantum states to generate encryption keys, ensuring theoretically unbreakable communication security. This approach is particularly suited for long-distance quantum communication while enabling resource sharing at the detector level.
The research, published in the prestigious journal Nature on February 11, 2026, addresses one of the most challenging aspects of quantum technology implementation: the miniaturization and integration of complex hardware. Previous QKD systems faced limitations due to the extremely high performance requirements for light sources and modulation devices, making chip integration exceptionally difficult.
Professor Wang emphasized that this demonstration represents the first successful implementation of a photonic quantum chip-based QKD network in over two decades of research. The chips exhibit remarkable uniformity during wafer-level fabrication, enabling cost-effective mass production capabilities. This technological advancement provides a viable pathway toward constructing even more extensive quantum communication networks with greater user capacity.
Nature’s peer reviewers recognized the work as a substantial contribution to quantum technology, noting the network’s exceptional scalability and describing the research as ‘undoubtedly of high impact for the quantum communication community.’ Academician Gong highlighted that this achievement will accelerate the miniaturization, practical application, and large-scale deployment of quantum communication systems worldwide.