Leveraging the pilot platform for new cloud-network integrated infrastructure and the large-scale sci-tech innovation facility, the China Telecom Research Institute, in collaboration with top-tier industry-academia-research teams including QuantumCTek, Yangtze Optical Fibre and Cable (YOFC), ZTE, and Beijing University of Posts and Telecommunications, has successfully achieved stable co-transmission of a 40Tbps (50 x 800Gbps) ultra-high-capacity classical optical communication system and a commercial Quantum Key Distribution (QKD) system over a 100-kilometer hollow-core fiber, setting a new global record for quantum-classical co-transmission systems.
While ensuring high-capacity transmission, the system achieves a secure key rate of 9.56kbps, effectively solving the challenge of nonlinear noise suppression in co-fiber scenarios and clearing a key technical obstacle for the large-scale commercial deployment of quantum-secure communications.
Quantum Key Distribution (QKD) is a core technology for achieving absolute security in information transmission, but it has long faced two major dilemmas: the high deployment cost of dedicated fiber cores, and the susceptibility to interference from classical signals during co-fiber transmission, making it difficult to integrate with existing high-capacity optical communication networks.
To address this bottleneck, the team pioneered a quantum-classical joint optimization scheme based on hollow-core fiber, incorporating the transmission characteristics of classical channels into a collaborative optimization framework for the first time. Through precise configuration of wavelength allocation and launch power, nonlinear noise was effectively suppressed, achieving a perfect balance between ultra-high-capacity classical transmission and high-security quantum key generation.
This technology can be seamlessly integrated with existing optical communication networks and rapidly deployed in high-security demand scenarios such as government affairs, finance, energy, electric power, rail transit, and data centers. It will be widely applied, particularly in the quantum security infrastructure led by China Telecom Quantum Information Technology Group, helping to build a large-scale, integrated transmission network with high throughput and density, providing strong support for constructing a secure, efficient, and intelligent information network.
Looking ahead, China Telecom will continue to join forces with industry partners to deepen research on quantum communication technologies, accelerate the implementation of "quantum + network" integrated applications, fully support the construction of the national communication security system, and contribute solid strength to the building of a strong cyber nation, the development of a digital China, and the high-quality growth of the digital economy.