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Optical Control of Light on a Silicon Chip
An anonymous reader writes "Researchers at Cornell University have demonstrated a device that allows one low-powered beam of light to switch another on and off, on silicon, a key component for future "photonic" microcircuits in which light replaces electrons for propagating signals. It is highly desirable to use silicon--the dominant material in the microelectronic industry--as the platform for these photonic chips.
The approach developed confines the beam to be switched in a circular resonator, greatly reducing the footprint required on the chip and allowing a very small change in refractive index to shift the material from transparent to opaque."
Daar is nie 'n lepel nie
I thought diffraction and interference was to be the answer to switching light. Does anybody know what happened to this technology?
What is the exact use for this? Is it's advantage that there's no need to switch back & forth between electric signals & optic signals in e.g. a optical router, or is a computer based on solely optical signals faster than one based on electrical signals?
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"The chances of a demonic possession spreading are remote -- relax."
Wasn't some light-something-or-other kind of CPU mentioned somewhere about a year or so ago? I remember that they got that one up to 8Ghz or something like that (must need a huge heatsink). Somebody refresh my memory...
READY.
PRINT ""+-0
One: Its faster than a normal circuits.
Two: It consume less power.
Timang tinggi tinggi
parang sudah asah
alang alang mandi
biar sampai basah
"FASTER THAN LIGHT COMPUTING!" ... uh, "fast-AS-light" in fact.
damn, never mind.
Any idea exactly how fast this would be? Its power requirements? How long until people start seeing this used in "real" situations?
What the poster and the article both neglect to mention for us simpler types is why silicon is desirable.
Is it simply because it requires less modification to the production pipeline, or is there another more scientific reason?
Perhaps a scientific slashdotter can enlighten us. Ahem.
These structures will find their first application in routing devices for fiber-optic communications.
That's a fantastic use...
But I'm more interested in optical computing.
In theory extrememly low power chips should be possible, but what is the absorption rate like, especially in terms of heat, and quantity of reused light.
That is ofcourse, assuming that this CAN be used for more sophistication chip design.
Has there been any suggestion of other uses, and if so, what possibilities are there available for such technology?
... make light work.
"Many hands make light work!"
The Cornell Nanophotonics Team
printf("Goodbye cruel world!\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b");
could this directly exploit optical fiber carried data ?
at this moment, we still need some converter in between, otherwise, we'd make it even faster than now.
Anyway, it might open us to new perspective... optical logics would be one, where we'd have "red", "green" and "blue" components which would be combined in some ternary/quaternary way (don't know which, yet).
Finally, this "color approach" also reminds me of some subparticle-related theory where color are also suggested...
Trolling using another account since 2005.
Finally, a use for all those colorful tubes of light.
Ooooo.....This should make my Christmas tree which uses fiber optics MUCH more interesting!
What's the darn switching time? Can't find it. The really important measurement and I can't find it.
Herriot-Watt were doing this on a physically bigger scale back in the 80s and managed something like a 10ms switch speed.
They are the ultimate optics GODS.
what Xerox created about a year ago with Optical MEMS?
Here is a Xerox Technology post about Optical MEMS which is an all optical switch using a silicon chip.
Optical MEMS Source
Imagine a beo... never mind
"allows one low-powered beam of light to switch another on and off" is that like using a flashlight to turn on a wall switch.
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I do not see any use for optics in processing even though photons theoritically travel faster than light. (Remember photons also do not travel at 3*10^8 in a waveguide eg silicon: velocity = c/refractive index and refractive index of silicon ~= 3.5)
although this would boost the oppurtunity for optics in processing... I do not believe it would be usefull in high speed processing simply because it would be drain lot of power (wall-plug efficiency is being worked on to improve right now!) but this could change..But one thing that cannot change is that the waveguides and devices (need to be atleast as big as the wavelength) are very big compared to the electronic devices...
here is a fair comparison of wavelengths.
-optical wavelength = 1.1 microns. electronic wavelength
-(electrons can be compared in energy to an x-ray photons and so wavelength of x-ray photon - this concept is used in electron microscopy) this is in nanometers 2 orders smaller.
so the electronic device sizes are 2 orders smaller and so lot more dense.
make love
make: *** No rule to make target `love'. Stop.
I never thought I'd see a resonance cascade, let alone create one..!
h to the izzo, v to the izzay. is that right? hova? what's that supposed to mean anyway? hova..
I, for one, welcome our new photonic-brained overlords.
Research on ring resonators has been ongoing for many years and this research at Cornell is great.
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In the boom a few years ago, Nanovations Technologies was a start-up that touted ring resonator technology (in InP not Si). They blew their wad on big trade show booths and bus ads. Nanovation also gave MIT a piece of paper that said they wil give $90Million for research over a period of six years: I don't think MIT got much cash.
Research for this company came out of Northwestern University. Manufacturing was to be in Michigan, Facility in Ottawa was Apollo which did (does?) FDTD modelling on Ring Resonators.
G. Robert Tatum, of AT&T fame, put Nanovations corporate offices in Bandwidth Bay, FL (beats the views of the suburbs of Motown and Evanston, IL).
Equipment at the Michigan manufacturing facilty was sold at a DoveBid auction.
The company had dedicated engineers but the managment was not on track. The twist in the matter was a holding company held (Stamford International) held shares in Nanovation. Stamford wanted more control in Nano but managed to fly the controls into bankruptcy.
http://www.lightreading.com/document.asp?doc_id
http://www.lightreading.com/document.asp?doc_
http://www.detnews.com/2001/busine
http://www.google.com/search?hl=en&lr=
http://web.mit.edu/
Those who know history are doomed to repeat it.
Like a similar technology from Lucent, the optical MEMS uses an electrical signal for the control signal.
While it DOES have the advantage over a fully electronic system in that the optical signal being acted upon is never converted, the control signal itself is electrical. In Lucent's version, an electrical signal would cause a small mirror to move, essentially deciding where the light beam aimed at the mirror would go. (Think of TI's DLP chips, same basic idea.)
This new development is *fully* optical. Even the control signal.
retrorocket.o not found, launch anyway?
I remember back in 1990, AT&T had a 4 bit optical computer on a lab bench. I believe it coded data in PCM laser patterns, which were stored in extremely long fiber spools (thousands of Km). Is there any descendant of that technology extant, where lasers are stored by traveling through extremely long distances in a medium?
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make install -not war
Nonlinear switching and wavelength conversion in
small rings has been shown before, perhaps not in
silicon. The use of absorption here is going to
give you a significant switching recovery time and switching energy (power consumption and heat dissipation). You will also probably find that the repetition rate was quite low, because the absorption-induced heating of the ring will also shift the resonance and cause a long-time-constant shift that can be troublesome. At a minimum this will induce bit pattern dependence.
Although I think the resonator enhancement of these nonlinear effects can be large and useful, one also needs to be aware that the ultimate speed is limited by the bandwidth of the resonance being used. The sharper the resonance, the higher the enhancement, but then the smaller the bandwidth. You are using the energy storage of the resonator to help you, but it takes time to "charge" and "discharge" it.
Anyway, good luck to them. I am a bit bemused
by the press splash, since there is quite a bit of
related work out there over a number of years.
But hey, keep at it.
Set the quantum spin states of photons leaving a laser, entangle pairs of them, and batch process them in these transphotors. 21st Century LAN parties happen frames per femtosecond and bits per picosecond.
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make install -not war
fishing for a M$ discount.
As my former advisor used to say in a very relatex context. Yes, if you build any kind of a waveguide (e.g., stripline or coplanar waveguide, or a real one, with metal walls) and send an electric pulse down that, the resulting wave will propagate all the way to the end. And the wave can be viewed as a PHOTON (except that lower frequency than optical).
If your metal is resistive, you'll dissipate some energy in that, the same as if your leght-transmitting medium is slightly opaque. But no, you do not need to feed extra power to keep the wave propagating.
The power dissipated in modern semiconductor processors (which do NOT use this mode of wave propagation, BTW) is mostly in CV^2/2 charging/discharging gate and line capacitors to sufficient voltage to open/close the next transistor.
Paul B.
And the wave can be viewed as a PHOTON
.
Um - any electromagnetic signal can be viewed as being transmitted by photons, whether it's an electromagnetic pulse down a waveguide, light propagating through free space, or someone changing a voltage on an electrical trace, causing it to switch.
In the voltage-switch case, the photons are virtual. In the free-space case, they're real. But they're still photons.
Electron-electron interactions are caused by (virtual) photons. Electrons can't interact with each other directly - there's no such interaction vertex (a three or four point electron vertex).
This is why electrical signals in a conductor propagate at (basically) the speed of light. The electric field is transmitting the signal, and the electric field is just virtual photon exchanges.
But no, you do not need to feed extra power to keep the wave propagating.
Electrical signals take a certain number of particles per second to generate a detectable signal. Photonic signals also would take a certain number of particles per second to generate a detectable signal.
For an equivalent signal/noise ratio, photons have the capability of requiring far, far less particles/second (because the noise floor is so much lower, and virtually everything is transparent enough to have virtually no "resistance"). Since particles/second is proportional to power in both cases (save in the case of a superconductor, but no one's going to suggest superconducting computers)
That's why I said it takes more power to transmit a signal electrically than photonically.
OK, ok, so it was a somewhat poor analogy. But it is true that resistive (or absorption) losses for an electronic chip are going to be significantly higher than for a photonic chip. Granted, resistive losses don't contribute much, but it doesn't make the argument wrong.
The only device that anybody should ever need to control light is "The CLAPPER".
You guys and your bloody semiconductor devices...
But this one caught my eye:
;-) In any case, superconductor technology is way more mature than anything that photonics can offer right now.
;-)
;-)
/. ?
(save in the case of a superconductor, but no one's going to suggest superconducting computers)
You know, it is funny but for the last 15 years of my life I've been personally involved with designing just such a beast and I can claim that I do suggest building it pretty soon...
Actually, the quote in GP Subj: was from my former adviser Prof. Kostya Likharev said in exactly this context: with Josephsonics you can get extremely sharp pulses (~1ps) propagating along superconductor transmission line with the speed of light (in medium) AND they also can easily interact with each other, unlike photons.
Well, I can continue this discussion if you find it entertaining...
Paul Bunyk
P.S. Reminds me of an old probability theory joke about conditional probabilities. OK, the odds that I look out my window and the first pedestrian I see is a man is about 1/2, odds that I see two men in a row is 1/4, etc. So, two guys made a bet, one betting that they will see 10 men in a row (1/1024, right?), the other thought that he was stupid, of course. They walked to the window and saw some kind of a military parade marching by on the street.
Now, what are the odds that you find a superconductor electronics guy on
Actually, the wave in the lake is carried by something akin to phonons (heck, they might be phonons - I hate fluid mech). That is, the wave is "transmitted" by quanta of the intermolecular forces, not by any particles in the medium itself.
What an unhelpful comment. Sure, the actual force is carried between charged poles and between particles By Pho[N]ons, uh huh, at rate C, of course, bravo for your brilliance.
The wave damn well does propagate through/via "particles in the medium itself". See that H2O bouncing up and down? Isn't the poor GP's illustration acceptable, Mr. Man?
Lastly, what the hell do photons have to do with fluid mech? It's not quantum electrodynamics, chummy.
Say it right: "Nuc-le-ah Powah".
What is the equivalent (silicon transistor) gate size for a photonic switch? (E.g., 13nm for recent silicon fab processes.)
How fast does it switch? (E.g., 2.4GHz for currently affordable Pentiums.)
Unless having 500 slashdotters perform the "wiki test" (deleting 5 articles and checking to see if they are rewritten) is your idea of fun...
Yeah. Would you choose a neurosurgeon who pokes around people's brains in his spare time? I wouldn't.