Record for fastest data rate set

February 11, 2016, University College London

A new record for the fastest ever data rate for digital information has been set by UCL researchers in the Optical Networks Group. They achieved a rate of 1.125 Tb/s as part of research on the capacity limits of optical transmission systems, designed to address the growing demand for fast data rates.

Lead researcher, Dr Robert Maher, UCL Electronic & Electrical Engineering, said: "While current state-of-the-art commercial optical transmission systems are capable of receiving single channel data rates of up to 100 gigabits per second (Gb/s), we are working with sophisticated equipment in our lab to design the next generation core networking and communications systems that can handle data signals at rates in excess of 1 terabit per second (Tb/s).

"For comparison this is almost 50,000 times greater than the average speed of a UK broadband connection of 24 megabits per second (Mb/s), which is the current speed defining "superfast" broadband. To give an example, the data rate we have achieved would allow the entire HD Games of Thrones series to be downloaded within one second."

The study, published today in Scientific Reports, used techniques from information theory and digital signal processing to custom build an optical communications system with multiple transmitting channels and a single receiver. As part of the EPSRC-funded UNLOC programme, the project set out to investigate ways to improve the optical network infrastructure to support the explosion of digital content, cloud and e-health services, as well as the ubiquitous connectivity of smart devices referred to as the Internet of Things (IoT).

Professor Polina Bayvel, the principal investigator of the UNLOC programme at UCL, said: "This result is a milestone as it shows that terabit per second optical are possible in the quest to reach ever higher transmission capacities in optical fibres that carry the vast majority of all data generated or received. A high-capacity digital communications infrastructure underpins the internet and is essential to all aspects of the digital economy and everyday lives."

The team determined the best way of encoding information in optical signals, taking into account the limitations of the transmitter and receiver. They then applied coding techniques commonly used in wireless communications, but not yet widely used in optical communications, to ensure the transmitted signals are adapted to distortions in the system electronics.

Using UNLOC's state-of-the-art lab facilities, the researchers built the new optical system and measured its performance. Fifteen channels, each carrying an optical signal of different wavelength were modulated using the 256QAM format typically used in cable modems, combined and sent to a single optical receiver for detection. By grouping the channels together, the team created a 'super-channel' which although not yet commercially available, is widely believed to be a way forward for the next generation of high-capacity communication systems.

"Using high-bandwidth super-receivers enables us to receive an entire super-channel in one go. Super-channels are becoming increasingly important for core systems, which transfer bulk data flows between large cities, countries or even continents. However, using a single receiver varies the levels of performance of each optical sub-channel so we had to finely optimise both the modulation format and code rate for each optical channel individually to maximise the net information data rate. This ultimately resulted in us achieving the greatest information rate ever recorded using a single receiver," said Dr Robert Maher.

In this study, the researchers connected the transmitter directly to the receiver to achieve the maximum data rate. They will now test the system and measure the achievable data rates in a long distance transmission scenario where optical signals can become distorted as they travel through thousands of kilometres of optical fibres.

Explore further: New technique doubles the distance of optical fiber communications

Related Stories

New optical transmitter enables better communication networks

January 29, 2016

All the world's data – pictures, video, sounds, and text – has to traverse complex networks of optical fibers that crisscross cities, regions, and countries. To better handle the glut of information, a research team from ...

New frontiers in communication systems

February 2, 2016

Data centres such as the ones used by Google and Facebook are the fundamental backbone for a range of services and applications including cloud and fog computing, big data, Internet of Things (IoT), social networking, weather ...

Recommended for you

Finnish firm detects new Intel security flaw

January 12, 2018

A new security flaw has been found in Intel hardware which could enable hackers to access corporate laptops remotely, Finnish cybersecurity specialist F-Secure said on Friday.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

neo09er
not rated yet Feb 12, 2016
Using multiple modulated carriers that are superpositioned at different frequencies is called OFDM, so why did they coin a new term, "super channel"? I have several clarifying questions:

1. Why must the carriers be frequency-multiplexed if each carrier gets its own physical channel? This seems overly complicated. Perhaps the author made a mistake and each physical channel has multiple subcarriers at different frequencies?

2. What is the bandwidth (complex sampling rate, presuming quadrature architecture) per subcarrier?

3. Are they planning on using digital pre-distortion to compensate for degradation in the fiber optic channel? If so, how much oversampling do they think they need?

4. What CPU or special DSP ASICs are needed to support the encoding/decoding, etc?
neo09er
not rated yet Feb 12, 2016
5. Why no 1024-QAM? This is achievable with today's technology. Maybe the bandwidth and coding rate inject too much EVM?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.