Search
Menu
PI Physik Instrumente - Revolution In Photonics Align LW LB 3/24

Signals amplified by light alone

Facebook X LinkedIn Email
The discovery that the force of light in a nanoscale switch is strong enough to move an optical waveguide without having to rely on the device’s mechanical structure could dramatically increase Internet download speeds while also consuming less power.

The microscale optical device, developed at the University of Minnesota, uses the force generated by light to flop a mechanical light-based switch on and off at very high speeds. This development could lead to advances in computation and signal processing using light instead of electrical current. “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 College of Science and Engineering.


University of Minnesota researchers led by Mo Li have invented a novel microscale mechanical switch of light on a silicon chip. The team says the technology could dramatically increase Internet download speeds while also consuming less power.


Li and collaborators discovered in 2008 that nanoscale light conduits can be used to generate optical forces strong enough to mechanically move an optical waveguide. With their new device, they found that its mechanical properties can be completely dominated by the optical force.

“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, each assigned a different color of light so they don’t interfere with each other. This noninterference characteristic ensures the efficiency of a single optical fiber to transmit more information over very long distances. 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.

Meadowlark Optics - Building system MR 7/23

The new device has two optical waveguides, each carrying a signal. Placed between the waveguides is an optical resonator in the shape of a microscale doughnut. In the optical resonator, light 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. That 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 optical signal can be many times higher than the control signal, the device functions like a mechanical relay to amplify the input signal.

The new optical relay device currently operates 1 million times per second, but the 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 includes graduate students Huan Li, Yu Chen and Semere Tadesse, and former postdoctoral fellow Jong Noh. The project received funding from the University of Minnesota College of Science and Engineering and the Air Force Office of Scientific Research.

The results were published online in Nature Communications (doi: 10.1038/ncomms2103).

For more on Mo Li and his 2008 work on nanoscale light conduits, see “Light Drives Nanomachines,” www.photonics.com/a35732.

Published: December 2012
Glossary
nano
An SI prefix meaning one billionth (10-9). Nano can also be used to indicate the study of atoms, molecules and other structures and particles on the nanometer scale. Nano-optics (also referred to as nanophotonics), for example, is the study of how light and light-matter interactions behave on the nanometer scale. See nanophotonics.
optical fiber
Optical fiber is a thin, flexible, transparent strand or filament made of glass or plastic used for transmitting light signals over long distances with minimal loss of signal quality. It serves as a medium for conveying information in the form of light pulses, typically in the realm of telecommunications, networking, and data transmission. The core of an optical fiber is the central region through which light travels. It is surrounded by a cladding layer that has a lower refractive index than...
optical waveguide
Any structure having the ability to guide the flow of radiant energy along a path parallel to its axis and to contain the energy within or adjacent to its surface.
resonator
A resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or stimulus is applied at a specific frequency, causing the system to oscillate with increased amplitude. Resonators are found in various fields and can take different forms depending on the type of waves involved, such as mechanical waves, acoustic waves, electromagnetic waves, or optical waves. Key points about resonators: Resonance: Resonance is a condition where a...
Air Force Office of Scientific ResearchAmericasbroadband communicationCommunicationsdownload speedelectricalfiber opticsHuan LiInternetJong Nohlight-based switchMinnesotaMo Linanonanoscale switchNature Communicationsoptical deviceoptical fiberoptical forceoptical relayoptical resonatoroptical waveguideOpticsoptomechanical effectoptomechanicsradio-frequency devicesResearch & TechnologyresonatorSemere Tadessesignal processingsilicon chipTech PulseUniversity of MinnesotaYu Chen

We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.