Slower light could mean faster computers

Dec 22, 2006

IBM today announced its researchers have built a device capable of delaying the flow of light on a silicon chip, a requirement to one day allow computers to use optical communications to achieve better performance.

Researchers have known that the use of optical instead of electrical signals for transferring data within a computer chip might result in significant performance enhancements since light signals can carry more information faster. Yet, "buffering" or temporarily holding data on the chip is critical in controlling the flow of information, so a means for doing so with light signals is necessary. The work announced today outlines just such a means for buffering optical signals on a chip.

"Today's more powerful microprocessors are capable of performing much more work if we can only find a way to increase the flow of information within a computer," said Dr. T.C. Chen, vice president of Science and Technology for IBM Research. "As more and more data is capable of being processed on a chip, we believe optical communications is the way to eliminate these bottlenecks. As a result, the focus in high-performance computing is shifting from improvements in computation to those in communication within the system."

Long delays can be achieved by passing light through optical fibers. However, the current "delay line" devices for doing so are too large for use on a microchip, where space is precious and expensive. For practical on-chip integration, the area of a delay line should be well below one square millimeter and its construction should be compatible with current chip manufacturing techniques.

IBM scientists were able to meet this size restriction and achieve the necessary level of control of the light signal by passing it through a new form of silicon-based optical delay line built of up to 100 cascaded "micro-ring resonators," built using current silicon complementary metal-oxide-semiconductor (CMOS) fabrication tools. When the optical waveguide is curved to form a ring, light is forced to circle multiple times, delaying its travel. The optical buffer device based on this simple concept can briefly store 10 bits of optical information within an area of 0.03 square millimeters. That's 10 percent of the storage density of a floppy disk, and a great improvement compared to previous results. This advancement could potentially lead to integrating hundreds of these devices on one computer chip, an important step towards on-chip optical communications.

The report on this work, "Ultra-compact optical buffers on a silicon chip," by Fengnian Xia, Lidija Sekaric and Yurii Vlasov of IBM's T.J.Watson Research Center in Yorktown Heights, N.Y., is published December 22 in the premiere issue of the journal Nature Photonics.

Source: IBM

Explore further: Clues to inner atomic life from subtle light-emission shifts

Related Stories

How oversized atoms could help shrink

14 hours ago

"Lab-on-a-chip" devices – which can carry out several laboratory functions on a single, micro-sized chip – are the result of a quiet scientific revolution over the past few years. For example, they enable ...

Could your smartphone one day tell you you're pregnant?

4 hours ago

Researchers at the Hanover Centre for Optical Technologies (HOT), University of Hanover, Germany, have developed a self-contained fiber optic sensor for smartphones with the potential for use in a wide variety ...

Recommended for you

Extreme lab at European X-ray laser XFEL is a go

5 hours ago

The Helmholtz Senate has given the green light for the Association's involvement in the Helmholtz International Beamline (HIB), a new kind of experimentation station at the X-ray laser European XFEL in Hamburg, ...

Restoration of NIST's million-pound deadweight machine

Jul 01, 2015

Restoration is well underway for NIST's 4.45-million newton (equivalent to one million pounds-force) deadweight machine, the largest in the world. The three-story-tall deadweight, comprising a stack of stainless ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.