Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Duke ’all-optical’ switch could advance light-based telecommunications

29.04.2005


Duke University physicists have developed a switching technique that uses a very weak beam of light to control a much stronger beam. The achievement could make optical telecommunications devices perform far more efficiently, and perhaps also aid in the development of futuristic quantum communications devices, the scientists said. "What’s important here is that this is an ’all-optical’ switch, using only light, with a weak beam affecting a strong one," said physics professor Daniel Gauthier, the Duke team leader.

Such a switching technique could improve today’s telecommunications switching arrays that must repeatedly and inefficiently convert light to electricity and then back to light -- a method especially impractical for very high speed telecommunications networks, Gauthier said in an interview.

Until now, Gauthier said, scientists have primarily demonstrated switching techniques that use stronger light beams to control weaker ones. "And that’s not very useful in a telecommunications networking device because you would need a lot of energy to switch a tiny amount," he said.



Gauthier and other team members will describe their findings in the Friday, April 29, 2005, issue of the research journal Science, in a report whose first author is Gauthier’s graduate student Andrew Dawes. Additional co-authors are Gauthier’s post-doctoral research associate Lucas Illing and former Duke physics undergraduate Susan Clark, who is now in graduate study at Stanford University.

Their research is funded by the Defense Advance Research Projects Agency, the National Science Foundation and the U.S. Army Research Office.

The Duke team’s switching system makes use of an instability that Gauthier initially studied in graduate school.

The scientists point two identical beams of laser light at each other while both opposing beams also pass through a warmed rubidium vapor trapped in a glass vacuum tube.

Normally, such counter pointed laser light beams would just unresponsively pass through each other, Gauthier said. But this laser light is of just the right infrared wavelength to be affected by the natural excitations of the rubidium atoms.

This interaction between the light and the rubidium atoms triggers an instability that creates two additional beams. When these secondary beams are projected on a screen, they form an optical pattern. That pattern, consisting of a pair of spots, can be rotated to a new alignment when a third "switching" beam is passed through the rubidium vapor.

Crucially, the strength of the switching beam is also much weaker than the original beams. According to their Science report, the Duke physicists have been able to operate their switch with beams up to 6,500 times weaker than the light in the optical pattern.

"So the idea is, we’ve got beams that are pointing in one direction and might be going down to a particular place in a network," Gauthier said. "Then, by putting in a very weak beam, we can rotate those original beams to a new orientation. So the spots could then go to different channels in a network system, for example."

The idea of such a weak signal controlling a stronger one "makes the switch ’cascadable,’" Gauthier said. "That’s what you need to be able to have the output of one switch affect the input of another switch downstream. No other group we know of has demonstrated this in an all-optical switch."

So far, the Duke group has used weak switching beams consisting of as few as 2,700 individual particles of light, known as photons.

Their report in Science also suggests possible techniques for using switching beams as weak as single photons, perhaps by reducing the size of the laser beams or modifying the atomic vapor.

"There are some applications in quantum information where you would like to have a switch that could be actuated with a single photon," Gauthier said. Quantum computing and telecommunications refers to systems that make use of the quirky features of quantum mechanics to solve otherwise intractable computational problems and provide secure communications channels.

Those quantum effects only manifest themselves in systems where individual photons, electrons or atoms can be manipulated.

Monte Basgall | EurekAlert!
Further information:
http://www.duke.edu

More articles from Physics and Astronomy:

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Quantum thermometer or optical refrigerator?
23.06.2017 | National Institute of Standards and Technology (NIST)

All articles from Physics and Astronomy >>>

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 >>>