China Unicom Completes 800G Transmission Capability Verification on the Live Network in Zhejiang Branch, Paving the Way for Ultra-High-Speed Interconnection of Data Centers

Recently, China Unicom completed the 800G transmission capability verification in Zhejiang province with Huawei, achieving transmission over 690 km on the live network. The company also verified key factors, such as system performance, transmission penalty, and hybrid transmission of 100G, 400G, and 800G at various modulation formats and spectrum widths. This is the first time to achieve smooth upgrade to 800G using existing G.652 fibre resources and a 400G transmission system, providing the technical guidance and network construction basis for ultra-high-speed interconnection of data centers in the intelligent era.

With the rollout of digital strategies in China such as the east-to-west computing resource transfer project, demand is surging for massive data transmission in scenarios such as cloud computing and large-scale data center interconnection (DCI). And as 400G QPSK technology matures, 800G technology that shares the same industrial chain can further improve the system capacity, and effectively reduce the per-bit transmission power consumption. Based on the 400G OTN trial network of China Unicom Zhejiang Branch, the 400G interconnections between nodes in Hangzhou, Wenzhou, and Taizhou had been upgraded to 800G. During verification, the system performance and transmission capability met expectations.

System capacity: Based on the optical-layer C6T + ROADM/OXC on the trial network, electrical-layer devices are upgraded from single-wavelength 400G with 100 GHz spectral width to single-wavelength 800G with 150 GHz spectral width. The system capacity is increased by one third to 32T, which meets the surging demand for traffic interconnection between data centers on the metro network.

System performance: The 800G system uses the PCS-16QAM modulation scheme to achieve transmission over 690 km in an EDFA system without Raman amplifiers on the trial network. The hybrid transmission with existing 100G and 400G channels had also been verified, with results showing that the existing ROADM network has no impact on the existing services and transmission performance during the upgrade to 800G, ensuring smooth and stable upgrade.

"The 800G transmission capability verification shows that 800G can meet the requirements on the metro network, such as interconnection of metro core nodes, multi-AZ data centers, active-active scenarios, and large-capacity interconnection including distributed deployment of intelligent computing," said Tang Yingqi, General Manager of Network Department of China Unicom Zhejiang Branch. "By actively implementing advanced optical transport technologies and applications, China Unicom Zhejiang Branch will contribute to the rapid growth of digital economy in the Zhejiang province."

"China Unicom has built a provincial 400G OTN trial network in Zhejiang in March last year," said Wang Guangquan, a network communications scientist and chief engineer of China Unicom Research Institute. "Based on this network, 400G optical-electrical synergy technology verification was completed in March this year. The 800G verification is another innovative practice of China Unicom in ultra-high-speed transport network technologies, greatly improving the per-bit transmission efficiency and reducing the per-bit transmission cost. We will continue to research and apply new key technologies of the next-generation optical network, and expect the trial network of China Unicom Zhejiang Branch to play an important role."

In the future, China Unicom will continue to explore and promote the development and application of ultra-high-speed optical communications network technologies, and continuously build a low-latency, high-bandwidth, high-reliability, and intelligent all-optical transport infrastructure for computing-network convergence services. By doing so, the operator can achieve high-quality transmission of computing services, contributing to the growth of China's digital economy.