A close-up of the photonics project. Image: Tyndall National Institute
Faster internet speeds and less power consumption – what’s not to love?
A breakthrough in materials for photonics applications could result in faster internet speeds by a considerable order of magnitude.
The discovery by a team of scientists – including postdoctoral researcher Dr Sebastian Schulz of Tyndall National Institute and the Centre for Advanced Photonics and Process Analysis (CAPPA) at Cork Institute of Technology – could also simultaneously reduce power consumption.
‘Depending on the power, light can change colour, direction or even its speed’
– SEBASTIAN SCHULZ
Schulz was working in conjunction with a team led by Prof Robert Boyd at the University of Ottawa, Canada, including Zahirul Alam and Dr Jeremy Upham, as well as Prof Israel De Leon at Tecnológico de Monterrey, Mexico.
Reducing the power consumed by the internet
Postdoctoral researcher Dr Sebastian Schulz. Image: Tyndall National Institute
Published in Nature Photonics, the new technology combines two known concepts: meta-materials consisting of arrays of antennas and a thin film of a non-linear material. In this team’s case, the antenna array is made from gold and the thin film from indium tin oxide (a transparent conductor typically used in solar cells and touchscreens), but the concept can also be used with a wide range of other materials.
Combining metallic antennas with a transparent conductor, the new meta-material has a much stronger optical response than is available in natural materials.
The strength of non-linear interaction is measured by the change in the refractive index that can be achieved. Usually this ranges around 0.001, but with this new material the team measured a refractive index change of 2.5.
Additionally, this change occurs on an extremely short timescale – within 1 picosecond (or one-millionth of one-millionth of a second).
Short response times are important, as the response time limits how many times a system can be switched per second and, therefore, the amount of data that can be processed. The short response time of this system makes it suitable for operation at terahertz (THz) speeds, 10 times faster than current core internet links.
Schulz explained that, because the non-linear response of most materials is typically extremely weak, non-linear optics have rarely been used up to now.
“Typical optical systems – ones using light, such as optical fibres used in the ICT industry – are linear. This means that the behaviour is independent of the amount of light in the system. If the incident light is doubled, the amount of light exiting the system is doubled.
“Yet, non-linear optical systems exist, where the behaviour does depend on the amount of light entering the system. In such systems, depending on the power, light can change colour, direction or even its speed, and the team would like to use these effects to manipulate light – for example, to imprint data on light to reduce the power consumption of the internet.”
