For this recording, a previously unstable conduction band was used for the first time. To give you an idea of ​​how fast this is, while the average fixed broadband speed in the US is 242.38 megabits per second, researchers reached speeds of 301 terabits per second.

They achieved this incredible speed by sending infrared light through tubular glass strips; This is generally how fiber optic broadband works. But they A spectral range never before used in commercial systems was used, called the “E-band”. This required the implementation of new, custom-made devices.

The results of the tests carried out using fiber cables laid on the ground were published by the Institute of Engineering and Technology (IET) in March. The team also presented the research at the European Optical Communications Conference (ECOC) in Glasgow in October 2023, but the paper has not been made public.

new horizons

• All commercial fiber optic connections transmit data over the cable in the C and L infrared bands of the electromagnetic spectrum; The specific infrared region used for Internet connections covers the range of 1,260 to 1,675 nanometers. For comparison, visible light covers a spectrum with wavelengths of approximately 400 to 700 nanometers.
• C-band and L-band between 1,530 and 1,625 nanometers are widely used in commercial communications because they are the most stable, meaning the least amount of data is lost during transmission. But scientists assume that: One day, the density of traffic will cause these two bands to get jammed.This means additional data transmission bands will be needed to increase bandwidth.
• The S band, adjacent to the C band and covering 1,460 to 1,530 nanometers, has been used commercially with two other bands in a system known as “wavelength division multiplexing” (WDM), in which all three ranges are identical. It is used to reach much higher speeds.

But, still early scientists have never been able to emulate a connection in the E-band because data loss in this region reaches an extremely high level — About five times higher than the C and L bands. Fiber optic cables, in particular, are susceptible to the effects of hydroxyl (OH) molecules, both during production and naturally in the environment, that can enter the tubes and break connections. The E-band is called the “water peak” band due to the extremely high transmission loss resulting from the absorption of infrared light by OH molecules in this region.

Stabilization of the “water peak”

In a new study, scientists have built a system that enables stable data transmission in the E-band. They demonstrated successful and stable high-speed data transmission using both the E band and the adjacent S band.

To maintain stable communication in this region of the electromagnetic spectrum, researchers created two new devices called “optical amplifiers” and “optical gain stabilizers.” The former helps amplify the signal over a distance, while the latter monitors each wavelength channel and adjusts the amplitude as needed. They embedded them in fiber optic cables to ensure that data could be transmitted in infrared light without the instability and loss normally inherent in connections in these bands.

For the last few years Aston University has been developing optical amplifiers operating in the E band, which is close to the C band in the electromagnetic spectrum but around three times wider. Before our device was developed, no one had successfully emulated E-band channels in a controlled manner,
– says Ian Phillips, professor of electronics and computer engineering at Aston University in Great Britain and one of the scientists working on this project.

Although 301 Tbit/s is an extremely high speed, other scientists have used fiber optic connections in recent years to demonstrate even higher speeds. For example, a team from NICT was established in November 2023 world record of 22.9 petabits per second — 75 times faster than the speed achieved by the Aston University team. They were using WDM technology but did not have access to E-band waves. They demonstrated this high-speed connection over a distance of 13 kilometers.