Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Finding the right soliton for future networks

15.05.2008
European researchers say their study of self-sustaining solitary light wave packets could result in a new generation of computers and optical telecommunications networks.

Using light rather than electronic or magnetic devices to store and move data is quicker, more energy efficient and cost-effective, and cavity solitons could be the key to unlocking this technology.

A soliton is defined as a wave, which once formed, maintains its shape while it travels at constant speed. Soliton waves are localised within a region and are able to react with other solitons and emerge unchanged. This is in contrast to normal waves that diffuse over time over ever larger regions of space, a phenomenon called dispersion.

Solitons were first documented in 1834 by John Scott Russell who, quite by chance, observed the phenomenon in a canal in Scotland where soliton waves formed in water. He was able to reproduce this phenomenon in a water tank.

It was not until the 1970s that scientists suggested optical solitons could exist in optical fibres. In the late 1980s French and Belgian scientists were able to transmit soliton pulses over a fibre-optic cable.

Since then there has been an increasing amount of research into solitons and their practical applications for the rapid transmission of data over long distances.

The EU-funded FUNFACS project was set up in 2005 to investigate a special type of soliton. Cavity solitons are solitary waves formed in an optical cavity capable of trapping light. FUNFACS follows on from an earlier EU funded project PIANOS, which demonstrated steady cavity solitons.

The scientists wanted to investigate fundamental properties of such optical solitons, and demonstrate a proof of principle for all-optical processing with solitons.

Prospect of exciting applications
The scientists believed there were properties unique to cavity solitons that could give rise to applications more advanced than what is possible using today’s technology. For instance, such solitons have the extraordinary property that they can be formed and destroyed – 'written and erased' – at the micrometer scale in such a cavity. The project has gone a long way toward advancing that theory.

The properties of cavity solitons are particularly applicable to the developing scientific fields of photonics and optoelectronics, which aim to use light as a method of storing, manipulating and transmitting data. The science could ultimately result in a new generation of computers and optical networks.

Optoelectronics employs the electrical effects of materials on light. The FUNFACS researchers first sought to demonstrate the viability of self-sustained cavity soliton lasers (CSL), both as continuous waves and as pulsed waves that can be switched on and off.

They worked from the premise that since a soliton in an optical fibre is self-sustaining once it has been created, a cavity soliton is similarly self-sustaining within its cavity after its creation.

Lasers (light amplification by stimulated emission of radiation) consist of a gain medium inside a highly reflective optical cavity. The gain medium, which can be solid, liquid or gas, is the major determining factor of the wavelength of operation, and other properties, of the laser.

The cavity is coupled to an energy supply directed to the gain medium. In the case of a CSL the gain medium is the semiconducting material.

The test CSL was based on an existing semiconductor laser type known as a vertical-cavity surface-emitting laser (VCSEL) which is used in a variety of applications, including those relating to optical telecommunications.

The device consists of a thin optical cavity sandwiched between two highly reflective mirrors, fabricated out of solid semiconducting material using state-of-the-art nanotechnology.

An all-optical future
The researchers were able to show that due to the self-sustaining properties of cavity solitons the energy input required to maintain them is small. They were also able to show CSLs can be switched on and off using light pulses.

The research results indicate that CSLs could play an important role in an all-optical telecommunications system, according to project coordinator Robert Kuszelewicz.

“In conventional systems data are switched and routed within the network by converting light pulses into electrical signals and back again which slows down communications and creates a lot of waste heat,” he says. “But by using CSLs the switching can be done just with the light pulses with no need to convert to and from electricity thus giving much greater transmission speed and efficiency.”

Other tests demonstrated that solitons are not restricted to a single location but could be moved across the plane of the semiconductor material with a controlled speed and direction of drift.

Multiple solitons can also co-exist in close proximity to each other without interacting. Brought closer still, they can bind to one another forming a sort of cavity soliton molecule. Finally, the tests demonstrated that an attempt to superimpose two of them results in one disappearing.

“This wealth of properties is an incomparable reservoir of new processing functions unavailable in more conventional electronic systems,” says Kuszelewicz.

The discoveries could lead to an evolution from the current use of chip-based semiconductors for data processing to a more flexible type of optical processing. The advantages of optical processing stem from the way data is stored.

Once data has been imprinted on a semiconductor chip, its location is permanently fixed, while data held using cavity soliton technology can be moved without changing or losing its character.

The advance could represent a major technological breakthrough, much in the same way as transistors replaced valves and were themselves replaced by microchips.

However Kuszelewicz believes such a breakthrough is still a long way in the future. The first practical applications could be in hybrid semiconductors using current technology coupled with optoelectronic technology based on cavity solitons.

He also points out the two technologies each have their own strengths and drawbacks and will continue to exist alongside each other for a long time to come.

The FUNFACS project received funding from the EU's Sixth Framework Programme for research.

Ahmed ElAmin | alfa
Further information:
http://cordis.europa.eu/ictresults/index.cfm/section/news/tpl/article/BrowsingType/Features/ID/89731

More articles from Information Technology:

nachricht Equipping form with function
23.06.2017 | Institute of Science and Technology Austria

nachricht Can we see monkeys from space? Emerging technologies to map biodiversity
23.06.2017 | Forschungsverbund Berlin e.V.

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>