Japan has set a new world record in internet speed by achieving 1.02 petabits per second (Pbps) over a distance of 1,808 kilometers. This is the equivalent of sending over one million gigabytes every second enough to download 10,000 ultra-HD 4K movies in just one second.
The breakthrough was made using a new kind of 19-core optical fiber that is only 0.125 mm thick, the same size as standard fiber cables used today. The achievement was made possible by a joint team from Sumitomo Electric Industries and Japan’s National Institute of Information and Communications Technology (NICT).
Their new fiber system is not just about speed. It also shows that massive amounts of data can travel long distances without losing strength or quality. This makes it one of the most promising technologies for the future of communication.
“In the post-5G society, the volume of data traffic is expected to increase explosively due to new communication services, and the realization of advanced information and communication infrastructure is required,” said the researchers.
This new technology could play a major role in building networks to support artificial intelligence (AI), 6G wireless systems, smart cities, the Internet of Things (IoT), and even virtual reality. It also shows promise for connecting cities and countries more efficiently in the future, especially as data traffic continues to grow at a fast rate.
Scientists around the world have tried to boost internet speeds by sending more data through fiber cables. But the problem has always been distance. While high speeds like this have been achieved before, it was only possible over short ranges — such as the 1.7 petabits per second the same Japanese team recorded in 2023, but that was only across 63.7 kilometers.
This time, they solved the problem of long-distance data loss using a special design. Think of today’s regular fiber cable as a single-lane road. The new 19-core optical fiber is like a 19-lane superhighway and it’s still the same size as the current cables. Each lane (or core) sends data on its own, and together they move a massive amount of information all at once.
Another challenge was signal weakening over distance. Signals in fiber cables lose strength the further they go, so amplifiers are used to boost them. But doing this for all 19 cores without mixing up the signals was a huge technical problem.
To solve this, the NICT team developed a smart amplification system. They used a mix of amplifiers that could handle two different types of light signals (C-band and L-band), and do it for all 19 cores at the same time. They then tested the fiber by creating 19 loops, each simulating a 21-pass journey through the cable adding up to 1,808 kilometers.
Once the signals reached the end, a 19-channel receiver collected the data. A digital processor then cleaned up any interference using a technology called MIMO (multi-input multi-output). The result was a clear and reliable 1.02 petabits per second transmission over a long distance.
Even more impressive was the “capacity-distance product” a measurement that multiplies how much data is sent by how far it goes. In this case, it reached 1.86 exabits per second-kilometer, the highest number ever recorded using standard-sized fiber cables.
This achievement was presented at the 48th Optical Fiber Communication Conference (OFC 2025). Experts say that while the system is not yet ready for commercial use, the test shows it is possible to build extremely fast, long-distance internet networks using existing fiber cable sizes. That would make it easier to upgrade current infrastructure without digging up roads or laying new pipes.
Sumitomo Electric developed the special 19-core fiber, designing it to reduce signal loss and improve data transmission. The NICT team created the transmission system, amplifiers, and signal receivers to work with the fiber and demonstrate its real-world use.
“This isn’t just about faster internet,” one NICT scientist said. “It’s about preparing our networks for a future where everything is connected — from AI and smart homes to self-driving cars and advanced communication systems.”
