Researchers at the Eindhoven University of Technology and the University of Central Florida have developed a new fiber optics cable capable of transmitting the contents of over 5,000 DVDs in a single second – a speed six times greater than the previous record. The advance could help us reach petabit-per-second speeds over the next few years, which will be crucial for keeping up with growing bandwidth demands.

By upgrading the equipment at both ends of the cable, IT experts have been able to improve the transmission speed of fiber optics by a factor of 10 every four years, keeping up with the increasing demands for internet traffic. However, over the next few years, this will no longer be enough. Fiber cables as they are currently being made face an inescapable speed limit of about 100 terabits per second. If we want to avoid a "capacity crunch" by the end of the decade, we'll soon need to replace them with new types of cables that are able to push that limit much further out.

A promising solution would be to switch to so-called "multi-core fibers." Traditional fibers transmit light pulses by bouncing photons across a single "core," a plastic or glass cylinder that runs along the entire length of the cable. Adding more cores could reduce the ratio of signal to noise and allow for more information to be sent at the same time.

Assistant professor Chigo Okonkwo and his team have done just that, creating a fiber with seven cores instead of a single one. In addition, a more energy-efficient signal processing algorithm allows each core to transmit three times more data than would normally be possible. Combining the two approaches, the researchers achieved a data rate of 5.1 Tbit/s on a single wavelength over a single fiber.

Transmitting information over fifty different wavelengths at the same time (a common practice in telecommunications) resulted in a record transmission rate of 255 Tbit/s (net 200 Tbit/s) over a 1 km cable, which is much faster than the current standard of 4-8 Tbit/s and six times faster than the previous record set only a few months ago.

Using multi-core fibers would get rid of the issues that come from the common alternative of simply increasing the intensity of the signal, which improves throughput but can create a lot of distortion and is also less energy-efficient.

The researchers also say that the individual fibers they created are under 0.2 millimeters in diameter, which is not significantly bigger than the cables we're already using.

This development represents an important step in reaching the target set by the European Commission of reaching petabit-per-second transmission speeds by the end of the decade.

A paper describing the results appears on the latest issue of the journal Nature Photonics.

Source: TU Eindhoven