the light chip

Bishadi · Aug 5, 2011

Now, researchers led by engineers at the California Institute of Technology (Caltech) are paving the way for the next generation of computer-chip technology: photonic chips. With integrated circuits that use light instead of electricity, photonic chips will allow for faster computers and less data loss when connected to the global fiber-optic network.

"We want to take everything on an electronic chip and reproduce it on a photonic chip," says Liang Feng, a postdoctoral scholar in electrical engineering and the lead author on a paper to be published in the August 5 issue of the journal Science. Feng is part of Caltech's nanofabrication group, led by Axel Scherer, Bernard A. Neches Professor of Electrical Engineering, Applied Physics, and Physics, and co-director of the Kavli Nanoscience Institute at Caltech.

In that paper, the researchers describe a new technique to isolate light signals on a silicon chip, solving a longstanding problem in engineering photonic chips.

An isolated light signal can only travel in one direction. If light weren't isolated, signals sent and received between different components on a photonic circuit could interfere with one another, causing the chip to become unstable. In an electrical circuit, a device called a diode isolates electrical signals by allowing current to travel in one direction but not the other. The goal, then, is to create the photonic analog of a diode, a device called an optical isolator. "This is something scientists have been pursuing for 20 years," Feng says.

Normally, a light beam has exactly the same properties when it moves forward as when it's reflected backward. "If you can see me, then I can see you," he says. In order to isolate light, its properties need to somehow change when going in the opposite direction. An optical isolator can then block light that has these changed properties, which allows light signals to travel only in one direction between devices on a chip.

"We want to build something where you can see me, but I can't see you," Feng explains. "That means there's no signal from your side to me. The device on my side is isolated; it won't be affected by my surroundings, so the functionality of my device will be stable."

To isolate light, Feng and his colleagues designed a new type of optical waveguide, a 0.8-micron-wide silicon device that channels light. The waveguide allows light to go in one direction but changes the mode of the light when it travels in the opposite direction.

A light wave's mode corresponds to the pattern of the electromagnetic field lines that make up the wave. In the researchers' new waveguide, the light travels in a symmetric mode in one direction, but changes to an asymmetric mode in the other. Because different light modes can't interact with one another, the two beams of light thus pass through each other.

Previously, there were two main ways to achieve this kind of optical isolation. The first way -- developed almost a century ago -- is to use a magnetic field. The magnetic field changes the polarization of light -- the orientation of the light's electric-field lines -- when it travels in the opposite direction, so that the light going one way can't interfere with the light going the other way. "The problem is, you can't put a large magnetic field next to a computer," Feng says. "It's not healthy."

The second conventional method requires so-called nonlinear optical materials, which change light's frequency rather than its polarization. This technique was developed about 50 years ago, but is problematic because silicon, the material that's the basis for the integrated circuit, is a linear material. If computers were to use optical isolators made out of nonlinear materials, silicon would have to be replaced, which would require revamping all of computer technology. But with their new silicon waveguides, the researchers have become the first to isolate light with a linear material.

Although this work is just a proof-of-principle experiment, the researchers are already building an optical isolator that can be integrated onto a silicon chip. An optical isolator is essential for building the integrated, nanoscale photonic devices and components that will enable future integrated information systems on a chip. Current, state-of-the-art photonic chips operate at 10 gigabits per second (Gbps) -- hundreds of times the data-transfer rates of today's personal computers -- with the next generation expected to soon hit 40 Gbps. But without built-in optical isolators, those chips are much simpler than their electronic counterparts and are not yet ready for the market. Optical isolators like those based on the researchers' designs will therefore be crucial for commercially viable photonic chips.

In addition to Feng and Scherer, the other authors on the Science paper, "Non-reciprocal light propagation in a silicon photonic circuit," are Jingqing Huang, a Caltech graduate student; Maurice Ayache of UC San Diego and Yeshaiahu Fainman, Cymer Professor in Advanced Optical Technologies at UC San Diego; and Ye-Long Xu, Ming-Hui Lu, and Yan-Feng Chen of the Nanjing National Laboratory of Microstructures in China. This research was done as part of the Center for Integrated Access Networks (CIAN), one of the National Science Foundation's Engineering Research Centers. Fainman is also the deputy director of CIAN. Funding was provided by the National Science Foundation, and the Defense Advanced Research Projects Agency
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http://www.sciencedaily.com/releases/2011/08/110804141714.htm

i told you............... the new generation of computing will be 'a light thing'

funny part is, Cal Tech is who wrote to me in 83 claiming my thesis on photo neuron conduction was incorrect (how the brain works).

that was three decades ago

but now look at the new generation of cal tech'ies....

get er done!

enjoy

Anarcho-Technocrat · Aug 5, 2011

Bishadi said: ↑

http://www.sciencedaily.com/releases/2011/08/110804141714.htm

i told you............... the new generation of computing will be 'a light thing'

funny part is, Cal Tech is who wrote to me in 83 claiming my thesis on photo neuron conduction was incorrect (how the brain works).

that was three decades ago

but now look at the new generation of cal tech'ies....

get er done!

enjoy
Click to expand...

Thesis huh? So you went for a PhD in Physics? Send me your thesis I am quite interested in how you were even capable of writing one when you don't understand simple grammar including sentences and paragraphs. If I were to guess, you are indeed a schizophrenic.

Bishadi · Aug 5, 2011

Anarcho-Technocrat said: ↑

Thesis huh?
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i have a thesis about you. Would you like to read it?

So you went for a PhD in Physics?
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i wrote/write many papers.

From how life works to extinctions to the transition of mass, energy, time and many philosophical applications in between.

ie..... if i was interested in titles, i would have more than newton, eistein, hawkins and jesus himself, combined. in fact, read a bit of most any theology, they each describe me in one fashion or another.

i know you wouldnt believe that last part but just imagine if someone was walking around that actually had the math the globe has been seeking and in that could define life and how to live forever, in the real sense, versus the 'beliefs' sense of what is real.

All them theologies talk about some day an idiot will walk and you have been arguing with that idiot the whole time.

ie.... i will put theology out of business, not to mention cern itself.

Send me your thesis I am quite interested in how you were even capable of writing one when you don't understand simple grammar including sentences and paragraphs. If I were to guess, you are indeed a schizophrenic.
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all three of us are a weeee bit whacked.

ie..... Me and myself can argue with each other, while i watch myself pick on me.

Heck it would be so easy to be like you and just own the world but i am not interested in being liked or the power of stardom, i only care for the life of the next generations. So a contrast exist in priorities between you and I.

I aint even interested in enabling a single life that is incapable of personal responsibility. That is why i wont publish the math (the name) to know.

The good ones will do what is right, when they feel it. While the idiots can be made a fool of, like the selfish toys they are.

Anarcho-Technocrat · Aug 5, 2011

bishadi said: ↑

i Have A Thesis About You. Would You Like To Read It?

I Wrote/write Many Papers.

From How Life Works To Extinctions To The Transition Of Mass, Energy, Time And Many Philosophical Applications In Between.

Ie..... If I Was Interested In Titles, I Would Have More Than Newton, Eistein, Hawkins And Jesus Himself, Combined. In Fact, Read A Bit Of Most Any Theology, They Each Describe Me In One Fashion Or Another.

I Know You Wouldnt Believe That Last Part But Just Imagine If Someone Was Walking Around That Actually Had The Math The Globe Has Been Seeking And In That Could Define Life And How To Live Forever, In The Real Sense, Versus The 'beliefs' Sense Of What is Real.

All Them Theologies Talk About Some Day An Idiot Will Walk And You Have Been Arguing With That Idiot The Whole Time.

Ie.... I Will Put Theology Out Of Business, Not To Mention Cern Itself.

All Three Of Us Are A Weeee Bit Whacked.

Ie..... Me And Myself Can Argue With Each Other, While I Watch Myself Pick On Me.

Heck It Would Be So Easy To Be Like You And Just Own The World But I Am Not Interested In Being Liked Or The Power Of Stardom, I Only Care For The Life Of The Next Generations. So A Contrast Exist In Priorities Between You And I.

I Aint Even Interested In Enabling A Single Life That Is Incapable Of Personal Responsibility. That Is Why I Wont Publish The Math (the Name) To Know.

The Good Ones Will Do What Is Right, When They Feel It. While The Idiots Can Be Made A Fool Of, Like The Selfish Toys They Are.

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Lololololololololololololololololololololol. I would like to see all ur posts on I can has cheezburger? Please upload them when ur done trolling.

Bishadi · Nov 8, 2011

Anarcho-Technocrat said: ↑

Lololololololololololololololololololololol..
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was that funny?

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