According to CoinMeta, Chinese researchers have set a new record in fiber optic transmission, achieving a speed sufficient to download 20,000 4K movies in one second. The team has created a world record in the field of fiber optic transmission by successfully implementing real-time bidirectional transmission over a 1,000-kilometer hollow fiber optic cable for the first time. This 1,007.48-kilometer link transmits 64 terabits per second in each direction, which is equivalent to downloading 160 50GB movies per second in each direction. The signal travels 1,000 kilometers in just 3.43 milliseconds, with light propagating through the hollow center of the fiber optic cable. Compared to traditional glass fiber optics, this reduces transmission time by about 30%. This breakthrough is particularly important for AI data centers that are hundreds of kilometers apart, as the latency and bandwidth between facilities directly affect the training and inference efficiency of large models.