With the national project "East-to-West Computing Resource Transfer" is in full swing, the network connecting "East Data" and "West Computing" needs to evolve to larger bandwidth and lower latency, providing a high-quality data transmission channel for the east-west computing infrastructure and carrying the feedback of computing results. The optical transmission network is also evolving to ultra-high speed and large capacity, flexible and open, collaborative intelligent control and other diversification, 400G has started commercialization, more attention was increased to 800G, and how to further enhance the transmission capacity based on spectrum expansion has become the subject that all professionals in the industry needs to jointly consider.