TECH

New fiber optic data transmission speed record

A new data transmission speed record of 450 terabits per second using an existing, commercially installed optical fiber link has been set by a team of engineers involving UCL researchers. The achievement was presented at the annual OFC optical fiber conference in March in Los Angeles, California, and breaks the existing record set by the same team in November by 50%.

A typical household internet connection provides internet speeds at about 80 to 100 megabits per second. This new record is approximately 4 million times faster.

Senior author Professor Polina Bayvel (UCL Electronic & Electrical Engineering) said, "This new record shows the potential, unused capacity of existing optical fiber networks. Being able to adapt and expand our existing infrastructure to support more data capacity than it was initially designed for will be essential to support growing data demands including for future AI-enabled networks and AI infrastructure."

The team sent a data transmission from the UCL Roberts Building in Bloomsbury, London to the Telehouse North datacenter near Canary Wharf in London, 19.5 kilometers away where the data then looped around and returned back to the Roberts Building, for a total travel distance of 39 kilometers.

Fiber optic cables transmit information over great distances by bouncing encoded infrared light pulses along flexible glass fibers. Individual wavelengths carry different channels of data and can be sent along at the same time as other wavelengths without interfering, allowing numerous channels of data to be sent at a time. These wavelengths are grouped together into various "bands" that span dozens or even hundreds of different wavelengths.

To broaden the bandwidth of data sent over the fiber optic cables, the research team greatly expanded the number of frequency bands transmitting data. Each new frequency range contains hundreds of individual frequency channels to the transmission, dramatically increasing the amount of data that could be sent.

Typical commercial fiber optics transmit data using the "C-Band" (or conventional band) of infrared light (between 1530 and 1565 nanometers wavelength) and the "L-Band" (between 1565 and 1625 nanometers wavelength). They contain 134 and 163 individual channels, respectively.

The researchers used additional frequency bands of data transmission to include the O, E and S-bands as well. The O-Band spans 1260 nm to 1360 nm and contains 493 channels, the E-Band spans 1360 nm to 1460 nm and contains 258 channels, and the S-Band spans 1460 nm to 1530 nm containing 225 channels. With nearly 1,000 additional channels to transmit data, the team was able to send data vastly faster than conventional fiber optic services.

They were able to add these additional frequency ranges by installing newly developed optical transmitters to send the wider-band signal, and receivers that can similarly receive the additional channels.

This new record is an important proof of concept that shows it's possible to send data using all five frequency bands over an existing, real-world installed optical fiber, rather than just in a lab demo.

Though not likely to boost home internet speeds any time soon, this technology has major implications for connecting together the large data centers and servers that make up the infrastructure of the modern Internet. The ever-increasing demand for high-speed transmission of vast quantities of data is fueled in large part by the rapid growth of cloud computing and AI services. Technologies like this would make it possible to get the best performance out of existing physical infrastructure with only limited modifications.

The researchers estimate that the commercial adoption of this technology to connect data centers and other internet infrastructure could happen in about three to five years' time.

Lead author Dr. Ruben Luis of the National Institute of Information and Communications Technology, Japan, said, "Being able to demonstrate these kinds of data speeds on existing, installed fiber optic networks shows the practicality of this technology. It's our hope that we can lay the groundwork to develop better, faster data networks that form the backbone of the Internet."

The work was carried out in partnership with the National Institute of Information and Communications Technology in Japan as part of an international collaboration that brings partners to the UK to use UCL's advanced experimental capability to carry out these experiments.

The research was accepted as a post-deadline research submission for the Optical Fiber Conference 2026 held in March in Los Angeles, which recognizes a very limited number of significant papers often highlighting a "first" or record-breaking demonstration.

In November, the same team set a transmission speed record of 300.28 terabits per second using four signal bands. This new work added an additional signal band, the "E" band, to the data transmission system, increasing the transmission speed by 50%.

In October 2024, members of the same research group demonstrated record wireless transmission speeds.

Provided by University College London