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Intel Announces Laser Breakthrough
AdmiralWeirdbeard writes "Intel has just announced a breakthrough in laser technology allowing a continuous laser wave on a silicon chip. Apparently they devised a method to sap the interfering field of electrons previously generated in silicon by the lasers. Intel says that hardware exploiting the advance might begin appearing at the end of the decade."
Silicon: is there anything it can't do? Seriously, it'll be interesting to see how this impacts optical storage, not to mention all the other places lasers are used.
I knew early on in college Raman would be the ultimate solution to many problems. I wasn't thinking about lasers at the time but I'm not surprised. Those scrumptious noodles. So cheap, so easy to prepare.
It's hard to believe that's how Micronians are made. Why don't we see it right now by having you both kiss one another?
That this will lead to optical computing, but after reading the BBC article its clear that they have it in mind to use this for optical switches in the telecomunications industry. If someone smart could come up with a silicon based optical NAND gate, we would all be happy campers.
The (first) article states the waveguide is 1.5x1.55micrometers and 48millimeters in length, Has it got the units right on that one?
No, those units look right. If you really read the first article, then you would have seen the picture of the die.
Ok it sounds cool... but what is the intended purpose of this breakthrough?
From TFA: The Santa Clara, Calif.-based company has created a chip containing eight continuous Raman lasers by using fairly standard silicon processes rather than the somewhat expensive materials and processes required for making lasers today.
OK, so I'm probably missing some major point here, but, define "expensive" for making lasers, given that there is a laser in every cheap £20 CD player, cheap £30 DVD player, cheap £5 laser pointer... Can't be that expensive, surely?
"She's furniture with a pulse"
The (first) article states the waveguide is 1.5x1.55micrometers and 48millimeters in length, Has it got the units right on that one?
Yes. The Nature article the guys published (20 Jan, vol 433, p292) on this says "4.8 cm".
IANAEE, so maybe its correct, but their going to refine it, or maybe its not linear.
Yes, of course they're going to develop this further. This is the first time they've achived continous-wave laser gain in silicon, obviously the next step is to increase it.
(A smaller cavity requires larger gain)
No it's not linear, the cavity is S-shaped.
Which one?
taken! (by Davidleeroth) Thanks Bingo Foo!
I'm sorry, but that is just Rong...
Authority questions you. Return the favor.
This is old stuff (see bottom note on the article, result was published in Oct 2004). Intel showed they can lase silicon with another laser. So how am I going to find another laser to pump this one ?
Silicon is indirect bandgap semiconductor. There is no easy way to make lasers out of it unless you introduce some traps to facilitate optical transistions. Can anyone explain how does it work ? -a
"...continuous laser wave..."
Aw, nuts. And I just bought my new Continuous Bacon Wave . <sigh>There's always an upgrade.</sigh>
The article didn't mention this, or I didn't see it, but wouldn't using lasers instead of wires really use a lot of power? Epecially when you start using a lot of them. But then again, maybe these are really low powered lasers and don't take much power at all. Anyone have any ideas or know anything about wires vs lasers?
Don't take life so seriously. No one makes it out alive.
Open up gaps between the secondary light source and receptors such that they criss-cross the inside of your desktop's case... web of light, home-brewed koyanisqatsi (sp?) sequel - I wouldn't mind having a larger box if it would work the way I'm seeing/imagining it...
Whaddaya know? Per the article, lasers really *are* cool! (cooler than wires anyway).
Take the 90-Day Challenge! http://rwmurker.bodybyvi.com/
Hybrid optical-electronic chips are ussed mainly in highspeed net hardware. $$$ is the reason you haven't seen them in your desktop. I am fascinated by it more than quantum because it seems far off.
optoelectronics defined by Intel article.
More info. Just google Optoelectronics.
Now I just need to steal Conscription from the Aztecs...
Fiber optics:
IIRC fiber optics networks still have to use electronic switches, hubs, routers, etc, that means that the data has to be converted from photonic to electronic and back at every switch/router/anything that actually processes it. This causes a huge slow down in comparison to what a pure light switch/router/etc. could perform.
It's based on Raman shifting. It's a nice way of getting longer wavelength light from shorter wavelength light, but you still need a pricey(non-silicon) laser to make it work. Furthermore, because the Raman process has limited efficiency, you end up loosing much of the efficiency of a conventional (non-silicon) diode laser.
It's only interesting because it can be electronically swiched on and off, so it represents a nice way of getting modulated light into a silicon waveguide. On the other hand, there are modulators with much better efficiency. So it's a cheap but inefficient modulator, which is also a wavelength converter.
what the big deal is about is basically that intels raman laser represents another step towards having cheap electron to photon interconnects (and cheap fiber optic amps, although funnily the said the efficiency was only around 5%, but i can still see its significance). i drool at the thought of having my CPU connected to my RAM via an optical bus!(and cheaply too i must add, as this is currently possible, but would be very costly)...or maybe even optical SATA, sweeet!
Yes, the purpose is to distract you from how poorly Intel's processor business has been doing lately.
The CHIP is 16mmx16mm, the waveguide built into the chip is "folded" to fit 1.5x1.55x48000 micrometers.
Bet it you look at a road map of any city, you will find that the sum of the length of all the lines on the page is greater then the any of lengths of the edges of the map, too.
But I have a more fundamental question, one which I have not been able to determine in spite of having read the cited articles (Yes, we A.C.s CAN read the fine articles on occasion):
WHAT IS THE WAVELENGTH OF THE OUTPUT???????????
IANASLS (I am not a silicon laser scientist), but if I was would I be able to calculate the wavelength from all the values tossed about in the articles? Continuous red lasers are no big deal, a continuous violet laser would be reasonably impressive (at least to me, but I like purple), a continous deep UV or better laser on a chip this size would make for lousy light shows at the planetarium but could bring the cost down on communications central offices by several orders of magnitude, even more so if the output can be tuned. Or something like that.
It took reading the Intel glossary to the Intel press release to find the following:
Wavelength conversion - The process of taking light of one wavelength (color) and changing it to another wavelength (color). In communications, more data can be transmitted by sending multiple wavelengths of light down the same optical fiber. Wavelength conversion allows the switching of data from one wavelength to another. The Raman effect in silicon can produce such a wavelength conversion.
Which still doesn't tell me the wavelength of the laser (or the range of wavelengths), but only that the effect Intel is exploiting COULD probably produce multiple wavelengths across some undefined range.
P.S. To all the news sites that took Intel's press release and just moved sentences around to make it look like some thought or maybe even research went into the writing instead of merely repeating the Intel press release, most universities (at least my alma mater) consider that a crime more heinous then 2nd degree murder. If you wanted to be a writer, WRITE!
Intel says that hardware exploiting the advance might begin appearing at the end of the decade.
And software exploiting said hardware will appear about 15 minutes later...
bytesmythe
Hypocrisy is the resin that holds the plywood of society together.
-- Scott Meyer
The advance in technology being announced here is Intel's solution to the Two Photon Absorption problem. This allowed the team of scientists referenced in the story you cite to take the pulsing silicon laser they announced then, and make it a continuous wave laser, which is being announced now.
But I should have linked the previous story as well... my bad.
Come read my stupid blagablog. Rants and Giggles
Using the Raman effect, the chip firm has produced an optically pumped laser, with outputs up to 9mW.
"We have proved that silicon can be considered as a gain material," said Mario Paniccia, director of Intel's photonics technology lab.
. . .
At 300mW pump input, the laser outputs around 6mW. The slope efficiency, with a 25V bias on the PIN diode, is 4.3 per cent. Half power linewidth is claimed to be better than 80MHz.
So what exactly does it mean that silicon is a "gain" material if the laser output is one 30th the energy of the pump input?
Also, they mentioned something about optical modulation in the article; do you know if this proof-of-concept chip can actually modulate the light? I wonder if just reversing the bias would do it . . .
Oh well. I guess I'll have to read the Nature article when I get to work. We have pretty nifty online access to a lot of scientific journals.
Si la vida me da palo, yo la voy a soportar Si la vida me da palo, yo la voy a espabilar
The laser is coherent because the emitted photons are in phase.
The best explanation I've seen for the coherence of stimulated emission is "Rereading Einstein on Radiation" by Daniel Kleppner in this month's issue of Physics Today. The explanation is that light-matter interaction can be modeled as a driving force applied to an oscillator (like a pendulum or spring). In the presence of a driving force, an oscillator absorbs or emits energy depending on its current phase with respect to the phase of the driving force. A simple example is pushing someone on a swing (which is a pendulum, and therefore an oscillator). If you push them at the right times, they swing higher and higher--the oscillator absorbs energy. If you pull on the swing at those times, they swing less and less--the oscillator loses energy.
In light-matter interaction, the electromagnetic attraction between an electron and an atomic nucleus can be modeled as a spring, and the driving force is an incident electromagnetic wave, i.e. incident light. In a stimulated emission process, an atom (oscillator) loses energy in the presence of an incident photon (driving force). If the energy is emitted as a photon exactly out-of-phase with the incident photon (fully anti-coherent), the two photons would destructively interefere, reducing the net energy of the system and therefore violating conservation of energy. In fact, if the emitted photon is anything other than exactly in-phase with the incident photon, conservation of energy is violated. Thus the emitted photon must be exactly in-phase with the incident photon, and is therefore fully coherent with the incident photon.
"It take 9 months to bear a child, no matter how many women you assign to the job."
"It take 9 months to bear a child, no matter how many women you assign to the job."
I rebut that link in this reply to one of your other comments. The feedback due to the mirrors does contribute to the spatial coherence of the beam, but ultimately it depends on the fact that the stimulated emission process is temporally-coherent (in-phase). A Q-switched laser is a simple counterexample (at least to an optical physicist). Another simple counterexample that I neglected to mention in that other post is this. According to your theory, if I remove the laser medium from the laser and shine light into the former laser from one end, the output from the other end should be spatially-coherent light. This non-laser laser is actually a device called a Fabry-Perot interferometer, and it does not cause spatially-incoherent light to become spatially-coherent (also a simple experiment to do in an optics lab). Thus feedback is insufficient to explain the spatial coherence of a laser.
:-p
For a proper treatment of coherence, I recommend Statistical Optics by Joseph Goodman, or if you're a masochist you can attempt to tackle Optical Coherence and Quantum Optics by Leonard Mandel and Emil Wolf.
"It take 9 months to bear a child, no matter how many women you assign to the job."