Researchers at the University of Science and Technology of China have deployed a multi-mode quantum relay network that achieves matter-matter entanglement over 14.5 kilometers of fiber.
The system, called Xinghan-2, was detailed in the journal Nature Photonics on May 7. It solves a key bottleneck in quantum communication by delivering both high transmission rates and high fidelity simultaneously.
The research team, led by Li Chuanfeng and Zhou Zongquan, developed a time-measurement protocol paired with multi-mode quantum memory. Photons no longer need to arrive at intermediate stations at the same time.
Reviewers noted that the entanglement distribution rate exceeds previous metropolitan relays by more than 100 times. The network maintained 78.6 percent fidelity across the 14.5-kilometer span while using existing fiber infrastructure.
Li Chuanfeng said the work marks the longest reported distance for matter-matter entanglement and moves the technology from lab proof-of-concept to urban network use.