Download GTA VI in less than a second? Japan’s internet speed can make it happen now

In a major breakthrough for the future of global communications, a team of international researchers led by Japan’s National Institute of Information and Communications Technology (NICT) and Sumitomo Electric Industries has achieved the world’s fastest long-distance optical data transmission. The team successfully sent data at a rate of 1.02 petabits per second over a distance of 1,808 kilometres, using a specially designed 19-core optical fibre.

To put it into perspective, this distance is roughly equal to the journey from Sapporo to Fukuoka in Japan, from Missouri to Montana in the US, or from Berlin to Naples in Europe. The amount of data transmitted in just one second is more than what all internet users worldwide typically use in a day.

This remarkable achievement, presented at the 48th Optical Fiber Communication Conference (OFC 2025) in April, sets a new world record for both speed and distance using any kind of optical fibre. The capacity-distance product reached 1.86 exabits per second-kilometre, the highest ever recorded.

While earlier attempts have managed to reach over 1 petabit per second, those were limited to shorter distances (under 1,000 km). The team overcame this by designing a low-loss, wide-bandwidth 19-core fibre, allowing signals to travel much farther without quality loss. The optical fibre was manufactured by Sumitomo Electric, which also ensured that the fibre had low losses across the commonly used C and L wavelength bands.

To maintain signal quality, the system used optical amplifiers, two per core, one for each band (C and L). In total, 180 wavelengths were used, each carrying data using a high-capacity format known as 16QAM (Quadrature Amplitude Modulation).

Previously, long-distance high-speed transmission was limited either by the number of cores or by signal loss over large distances. But this new development shows that with the right design and amplification systems, scalable and long-range high-speed networks are possible.

The work is part of a larger push by NICT and global researchers to explore new fibre types, such as multi-mode and coupled-core fibres, to break past current technological limits. While past experiments using these fibres showed promise, they were often limited by complex signal processing challenges. This latest result using coupled-core 19-core fibre over long distances is a strong step forward.