Time Lens Speeds Up Optical Data Transmission

Sep 28, 2009 by John Messina weblog
This silicon chip is patterned with waveguides that split optical signals and combine them with laser light to speed data rates.
Credit: Alexander Gaeta

(PhysOrg.com) -- Researchers at Cornell University have developed a device called a "time lens" which is a silicon device for speeding up optical data. The basic components of this device are an optical-fiber coil, laser, and nanoscale-patterned silicon waveguide.

Current methods for speeding up optical data transmission require bulky and expensive optical equipment and consume a lot of energy. This new device is both energy efficient and is incorporated on a chip. This makes it ideal to move large quantities of data, at speeds up to 270 gigabits per second over telecommunication facilities and other optical devices.

Alexander Gaeta, Cornell University Professor of Applied and Engineering Physics, explains: "As you get to very high data rates, there are no easy ways of encoding the data." Alexander Gaeta has been one of the foremost developers of the new silicon time lens, alongside with his colleague Michael Lipson, who is a Cornell University associate professor of electrical and computer engineering. Their accomplishment can be found in the latest issue of the renowned scientific journal, Nature Photonics.

Keren Bergman, Columbia University Professor of Electrical Engineering, explains: "Power consumption is becoming a more constraining issue, especially at the chip level. You can't have your laptop run faster without it getting hotter." Optical chips can make computers run much faster without generating the un-necessary heat. Using an ultrafast modulator, it can compress data encoded with standard equipment to very high speeds.

The "time lens" uses a signal encoded on laser light using a conventional modulator. The modulated light signal is then attached to the silicon chip through an optical-fiber coil that sends it to a nanoscale-patterned silicon waveguide. On the chip, the signal interacts from a laser, which causes it to split up into different frequencies. The light travels through another strand of fiber cable and sends it to another nanoscale-patterned silicon waveguide, where it interacts with light from the same laser. In the process the signal is re-assembled but with its phase changed. The signal leaves the via another fiber cable at 270 gigabits per second.

The physics behind the process is very complex but the outcome is accomplished by taking a stream of bits that are traveling slow and making them travel much faster, says Keren Bergman.

By staying with silicon, "you can leverage all the technologies that have been developed for electronics to make optical devices," says Alexander Gaeta of Cornell University.

Via: Technology Review

© 2009 PhysOrg.com

Explore further: Nanospiked bacteria are the brightest hard X-ray emitters

Related Stories

A Broadband Light Amplifier on a Photonic Chip

Jul 06, 2006

Cornell University researchers have created a broadband light amplifier on a silicon chip, a major breakthrough in the quest to create photonic microchips. In such microchips, beams of light traveling through ...

Photonics: Pump up the bandwidth

Jun 21, 2006

U.S. scientists say they've developed an optical amplifier based on silicon that works across a wide range of frequencies.

Researchers develop ultrafast oscilloscope on a chip

Nov 06, 2008

(PhysOrg.com) -- As photonics -- using beams of light in place of electricity for communications and computing -- becomes more common, engineers need new tools for troubleshooting. Now researchers at Cornell ...

Fiber-optic booster on a chip

Feb 20, 2008

More and more of our communications -- from text messages to high-definition television -- travel over optical fiber. At last count the United States was crisscrossed by more than 80 million miles of it, with ...

Recommended for you

To conduct, or to insulate? That is the question

Jul 02, 2015

A new study has discovered mysterious behaviour of a material that acts like an insulator in certain measurements, but simultaneously acts like a conductor in others. In an insulator, electrons are largely stuck in one place, ...

Soundproofing with quantum physics

Jul 02, 2015

Sebastian Huber and his colleagues show that the road from abstract theory to practical applications needn't always be very long. Their mechanical implementation of a quantum mechanical phenomenon could soon ...

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

Jul 02, 2015

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, ...

User comments : 7

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 28, 2009
quantum particle entanglement is much more secure
and faster.
not rated yet Sep 28, 2009
Wow this article had 0 content. I'm a physics major and I couldn't make head or tails of it.
3.5 / 5 (2) Sep 29, 2009
Apparently, they alter the phase of the signal by decomposing it and recomposing it with nanoscale waveguides. I'm guessing this divide and conquer strategy, when coupled with the nanoscale patterning, results in a significant increase of the speed of light in the chip, which means the signal gets negative lag. Hence the name, time lens.

Now, what would happen if you put several of these in series?
not rated yet Sep 30, 2009
I'm guessing this divide and conquer strategy, when coupled with the nanoscale patterning, results in a significant increase of the speed of light in the chip, which means the signal gets negative lag.

Actually, I am pretty sure they only affect the wave speed, which is ok since that is how the data is transmitted.
5 / 5 (1) Sep 30, 2009
But since the wave is a laser beam, isn't that the same thing? To clarify a bit, I am talking about the speed of light in that particular medium, or velocity of propagation as I've found out it's called.

The signal enters the chip at a certain speed and with a certain phase. The speed increases in the chip, which leads to the signal exiting with a positive phase difference relative to the input signal(i.e., it "travels into the future"), while the speed reverts to that of the optic fiber.

I'm just speculating, though. And learning new things while doing so. Do correct me as necessary.
not rated yet Sep 30, 2009
So, sure, the end result is that signal appears to be sped up. You are right that it "travels into the future".
It's just that, as a photon, I do not think the light is actually sped up, I'd need to look into it more, it has been a while since I studied any of this.
not rated yet Oct 04, 2009
This has nothing to do with fastness: http;//google.com/groups?q="Comparisons+for+the+illiterate"

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.