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 Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>