Scientists at Aston University in the U.K. reached a new milestone in fiber-optic data transfer, achieving speeds of 402 terabits per second (Tbps). The key to this data-transfer record was using all the wavelength bands in fiber-optic cables. Traditionally, only one or two bands are used in most broadband connections.

The new record is 25% faster than the previous 301 Tbps, set by the same team in March. Back then, they used four of the six wavelength bands available in fiber-optic cables. By expanding their use to all six bands, the team achieved an unprecedented 402 Tbps speed.

To put things into perspective, Netflix recommends an internet connection speed of 3 Mbit/s or higher in order to stream high-definition media without interruptions. The record-breaking data transfer speed achieved at Aston is over 100 million times faster. 

Firing on all bands

The research team built the first optical transmission system that spans all six wavelength bands used in fiber-optic communications: O, E, S, C, L, and U. These bands correspond to different infrared wavelengths, ranging from 1,260 to 1,675 nanometers (nm). Visible light, for comparison, spans 400 to 700 nm.

Currently, most commercial fiber-optic connections use the C-band and L-band wavelengths (1,530 to 1,625 nm) because they offer the most stable transmission with minimal data loss. However, as network congestion grows, these bands may become saturated, necessitating the use of additional bands.

In previous experiments, the researchers had managed to stabilize connections using the E-band. This was despite it having higher data loss rates due to exposure to hydroxyl (OH) molecules that disrupt signals. In the latest study, they overcame this by developing new equipment to utilize the O-band and U-band wavelengths effectively. The researchers created devices to amplify signals in these bands using standard commercially available amplifiers for the O-band and specially designed amplifiers for the U-band.

“This finding could help increase capacity on a single fiber so the world would have a higher performing system,” said Aston University’s Ian Philips.

What’s particularly stunning is that these record-breaking speeds were achieved using standard commercial fiber-optic cables, implying that no specialized infrastructure is required to attain such high speeds. This could pave the way for broader adoption and implementation of the technology.

“It is expected that the data-rate of optical transmission systems required to enable “Beyond 5G” information services will increase enormously. New wavelength regions enable deployed optical fiber networks to perform higher data-rate transmission and extend the useful life of existing network systems. It is also anticipated that new bands can address the increasing demand of next generation communications services by combining with new types of optical fibers,” the researchers wrote in their preliminary paper.

The results of the experiment were accepted as a post-deadline paper at the 47th International Conference on Optical Fiber Communications (OFC 2024) in the USA on 28 March.