Using light to control light: Engineers invent new device that could increase Internet download speeds

Oct 02, 2012
University of Minnesota researchers have invented a novel microscale mechanical switch of light on a silicon chip. Credit: University of Minnesota

(Phys.org)—A team of scientists and engineers at the University of Minnesota has invented a unique microscale optical device that could greatly increase the speed of downloading information online and reduce the cost of Internet transmission.

The device uses the force generated by light to flop a mechanical switch of light on and off at a very high speed. This development could lead to advances in computation and using light instead of electrical current with higher performance and .

The research results were published today in the online journal Nature Communications.

"This device is similar to electromechanical relays but operates completely with light," said Mo Li, an assistant professor of electrical and computer engineering in the University of Minnesota's College of Science and Engineering.

The new study is based on a previous discovery by Li and collaborators in 2008 where they found that nanoscale light can be used to generate a strong enough optical force with light to mechanically move the optical waveguide (channel of information that carries light). In the new device, the researchers found that this force of light is so strong that the of the device can be dominated completely by the optical effect rather than its own mechanical structure. The effect is amplified to control additional colored at a much higher power level.

"This is the first time that this novel optomechanical effect is used to amplify optical signals without converting them into electrical ones," Li said.

Glass optical fibers carry many communication channels using different colors of light assigned to different channels. In optical cables, these different-colored light channels do not interfere with each other. This non-interference characteristic ensures the efficiency of a single to transmit more information over very . But this advantage also harbors a disadvantage. When considering computation and signal processing, optical devices could not allow the various channels of information to control each other easily…until now.

The researchers' new device has two optical waveguides, each carrying an optical signal. Placed between the waveguides is an optical resonator in the shape of a microscale donut (like a mini-Hadron collider.) In the optical resonator, can circulate hundreds of times gaining intensity.

Using this resonance effect, the optical signal in the first waveguide is significantly enhanced in the resonator and generates a very strong optical force on the second waveguide. The second waveguide is released from the supporting material so that it moves in oscillation, like a tuning fork, when the force is applied on it. This mechanical motion of the waveguide alters the transmission of the optical signal. Because the power of the second can be many times higher than the control signal, the device functions like a mechanical relay to amplify the input signal.

Currently, the new optical relay device operates one million times per second. Researchers expect to improve it to several billion times per second. The mechanical motion of the current device is sufficiently fast to connect radio-frequency devices directly with fiber optics for broadband communication.

Li's team at University of Minnesota includes graduate students Huan Li, Yu Chen and Semere Tadesse and former postdoctoral fellow Jong Noh. Funding support of the project came from the University of Minnesota College of Science and Engineering and the Air Force Office of Scientific Research.

Explore further: Engineers develop new sensor to detect tiny individual nanoparticles

More information: Multichannel cavity optomechanics for all-optical amplification of radio frequency signals, www.nature.com/ncomms/journal/… full/ncomms2103.html

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Sonhouse
5 / 5 (1) Oct 02, 2012
So as it stands with 1E6 flips per second, it could transfer a signal at CD level, 44,100 samples per second, x2 for stereoX 16 bits, of an rf signal running about 700 Khz. If they get it a thousand times faster at 1 billion, it could convert RF at CD level at 700 mhz. Big if though.
kevinrtrs
2 / 5 (3) Oct 02, 2012
Excellent!
gonegahgah
1 / 5 (1) Oct 02, 2012
Does this circulating light produce a more localised effect; more like a charge?
GenesisNemesis
1 / 5 (1) Oct 02, 2012
Can it be optimized with graphene?
ForFreeMinds
2 / 5 (3) Oct 03, 2012
What a bright idea
aroc91
not rated yet Oct 03, 2012
Kevin's comment should be removed citing the rule against pointless verbaige, for which I have had longer comments removed. No double standards, moderators.
vidyunmaya
1 / 5 (1) Oct 03, 2012
Looks like coaxial wave-guide motion effect