With the vigorous development of digital infrastructure and innovative business applications such as computing power networks, the Internet of Things, and data centers, the demand for networks continues to grow, which has given rise to the demand for large-traffic interconnection between cross-regional nodes and centers and promoted the further evolution of backbone transmission technology. upgrade. Under this opportunity, 400G backbone all-optical network technology has been widely discussed by academia and industry in recent years. This technology is also generally considered to be the future development trend of backbone transmission networks.

    With the rapid development of artificial intelligence, big data, cloud computing and other technologies and the large-scale construction of the "Eastern Digital and Western Computing" project, the network is undergoing unprecedented changes. Around 2008, the concept of all-optical networks first appeared in China, and building all-optical networks and all-optical cities became a vision across the country. Since 2013, 100G OTN has been widely used and has been used for 10 years. However, the core requirements of a computing power network are large bandwidth, low latency, and wide connectivity, so that the network can reach everywhere, computing power can be everywhere, and intelligence can reach everywhere. Facing the current huge computing power network market demand, traditional 100G is obviously unable to meet the new needs of users for related services. Against this background, all ends of the industry chain are actively promoting iterative development in technology, standardization, etc., seeking a more solid foundation for optical networks with higher speeds, larger capacities, and lower energy consumption. 400G, which is currently attracting much attention from the industry, is generally considered to be the next major revolutionary intergenerational technology for backbone networks, and is expected to become the "optical base" in the era of computing power networks.

   "Data show that global Internet traffic continues to grow at a rate of 26% every year; and Internet users are also growing massively, resulting in the emergence of massive 5G interconnection equipment and new bandwidth-intensive applications." According to Zhang Chengliang, president of the China Telecommunications Research Institute, the current The network architecture is changing: CDN is moving down, DCN is being built, and east-west traffic is increasing. The Internet has shown new characteristics in that video services are the mainstay, and the traffic of mid-range metropolitan area networks and data centers exceeds that of long-distance backbone networks. The rapid growth of Internet services has driven the development of large-capacity transmission technology. The next generation backbone network will adopt the 400G QPSK@150GHz technical solution.

   As the core carrying technology of the next generation backbone network, 400G increases system bandwidth by 4 times compared with 100G OTN, transforms transmission from "single lane" to "four lane", saves power consumption by more than 10%, and reduces latency by 10%. It is equivalent to laying a "viaduct" on the "Computing Network Expressway", which can realize the efficient circulation of computing power across regions and truly achieve strong computing through the network.