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Intel Hardware

Intel Devises Chip Speed Breakthrough 465

Chad Wood writes "According to the New York Times (free reg. req.), Intel has demonstrated a research breakthrough, making silicon chips that can switch light like electricity. The article explains:''This opens up whole new areas for Intel,' said Mario Paniccia, a an Intel physicist, who started the previously secret Intel research program to explore the possibility of using standard semiconductor parts to build optical networks. 'We're trying to siliconize photonics.' The invention demonstrates for the first time, Intel researchers said, that ultrahigh-speed fiberoptic equipment can be produced at personal computer industry prices. As the costs of communicating between computers and chips falls, the barrier to building fundamentally new kinds of computers not limited by physical distance should become a reality, experts say.'"
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Intel Devises Chip Speed Breakthrough

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  • Google link (KW) (Score:5, Informative)

    by jaxdahl ( 227487 ) on Wednesday February 11, 2004 @08:15PM (#8254673)
    No req. required [nytimes.com]
  • by Anonymous Coward on Wednesday February 11, 2004 @08:15PM (#8254675)
    "We've taken two AMD chips and put them both dual configuration with a giant 'Intel' sticker on top. Then, we sell it for twice what we paid, and get the lusers... err, I mean... users to buy it because it says 'Intel Inside.'"
    • by TheDukePatio ( 621176 ) on Wednesday February 11, 2004 @08:58PM (#8255055)
      What's more likely is that they had a couple highschool kids lower the chips 2", crazy glue a spoiler on, install neon undercarriage lights, a fake pushbutton labeled "Nitrous", and stickers, LOTS of stickers.

      New Codename: Ricer

  • mmmm (Score:4, Interesting)

    by josh3736 ( 745265 ) on Wednesday February 11, 2004 @08:16PM (#8254676) Homepage
    So when do I get my new high-speed fiber line? :D
    • MODS ON CRACK (Score:5, Insightful)

      by Dasein ( 6110 ) <tedc&codebig,com> on Wednesday February 11, 2004 @09:39PM (#8255308) Homepage Journal
      This question is not off-topic. They talk about being able to do optical switching at consumer prices.

      So the immediate question that I have is, "Why would I, a consumer, want that?" One possible answer is that I have fiber to my house.

      Short of that, why would I want it? Would I want to convert my existing network to optical. Nope, I want less wires instead of more wires. One of the quotes even talks about people being able to watch multiple views of the Superbowl.

      No, the mod that said this was on topic is full of crap.
  • by jafac ( 1449 ) on Wednesday February 11, 2004 @08:16PM (#8254681) Homepage
    that it will have to be x86 compatible, or it will never fly.
  • EMP (Score:5, Funny)

    by potpie ( 706881 ) on Wednesday February 11, 2004 @08:16PM (#8254683) Journal
    This kind of technology seems like a very healthy step toward making computers resistant to electromagnetic waves and/or pulses (aided also by the rise of optical storage devices), which is great for us humans now. But now what are we going to use against the "squiddies" when they come for our hovercrafts?
    • Re:EMP (Score:5, Funny)

      by jsse ( 254124 ) on Thursday February 12, 2004 @01:39AM (#8255693) Homepage Journal
      This kind of technology seems like a very healthy step toward making computers resistant to electromagnetic waves

      Your joke reminded me of an instance when I saw a co-worker sitting on a P-IV box while working on it. I took the chance to play some prank on him.

      "It could fire your 'eggs'"
      "You know what clock speed this thingy is running?"
      "2.4GHz, why?"
      "What's the wave frequency of a microwave oven?"
      (jumping up)"....OH SHIT"

      (It's just a joke. I don't think the CPU has enough strength to fry your 'eggs'. Even so, the wave can't penatrate the metallic case) :)
  • Still binary.. (Score:4, Insightful)

    by dustinbarbour ( 721795 ) on Wednesday February 11, 2004 @08:17PM (#8254689) Homepage
    When we get off of binary, then we'll be making progress, in my humble opinion. I mean, we've been using binary for-ever! Imagine the size and speed gains we would get if we could now have three or four states per bit.
    • why do you think there will be size and speed gains?

      the complexity of most logical and arithmetic operations that have to be performed on a bit increase exponentially with the number of possible states in the bit.

    • by _ph1ux_ ( 216706 ) on Wednesday February 11, 2004 @08:25PM (#8254761)
      01111001 01100001 00101100 00100000 01001001 00100000 01110100 01101111 01110100 01100001 01101100 01101100 01111001 00100000 01100001 01100111 01110010 01100101 01100101 00100000 01110111 01101001 01110100 01101000 00100000 01111001 01101111 01110101 00100000 01101111 01101110 00100000 01110100 01101000 01101001 01110011 00100000 01101111 01101110 01100101 00100000 00101101 00100000 01101000 01101111 01110000 01100101 01100110 01110101 01101100 01101100 01111001 00100000 01101001 01110100 00100000 01110111 01101001 01101100 01101100 00100000 01101000 01100001 01110000 01110000 01100101 01101110 00100000 01110011 01101111 01101111 01101110 00101110 00100000 01001001 00100000 01100001 01101101 00100000 01110111 01100101 01100001 01110010 01101001 01101110 01100111 00100000 01101111 01110101 01110100 00100000 01110100 01101000 01100101 01110011 01100101 00100000 01110100 01110111 01101111 00100000 01101011 01100101 01111001 01110011 00101110 00101110 00101110

      Know what I mean?
    • by condition-label-red ( 657497 ) on Wednesday February 11, 2004 @08:26PM (#8254773) Homepage
      Doesn't the "bi" in "bit" mean two? So we would have to call three states a "trit"; and four states a "quit" to keep them straight.
    • by irokitt ( 663593 ) <archimandrites-iaur AT yahoo DOT com> on Wednesday February 11, 2004 @08:30PM (#8254817)
      You know, maybe you are right. And I think we should also stop counting in base-10. I mean, we've been doing that for, like, forever. And it would be so cool to count in base-13. And maybe we should live in tepees. Because they're cool.
    • Re:Still binary.. (Score:5, Informative)

      by HeX314 ( 570571 ) on Wednesday February 11, 2004 @08:30PM (#8254825) Homepage
      The difficulty with mastering tri-state and quad-state computers (as opposed to bi-state or binary) comes with the gates used. How would one perform an inverse operation when there are two other choices from which to choose? Instead of AND, OR, and NOT (not to mention combinations such as XOR, NOR, NAND, etc.), you would have at least 8 gates (if I recall correctly; I worked on something similar to this during the summer) doing things such as shifting, reversing, "inverting," and such. The different permutations of these make it even more confusing.

      In addition to this, you would need to find a medium capable of carrying a tri-state signal (electrons are not best suited for this). In fact, due to the fact that we have a tough time determining on and off sometimes, I would personally suggest we leave it at binary for the time being.

      I know it's a long post, but most of it is necessary.
      • Re:Still binary.. (Score:5, Insightful)

        by Genda ( 560240 ) <mariet@NoSPaM.got.net> on Thursday February 12, 2004 @03:58AM (#8256218) Journal
        Dude, This is Light!

        Photonics have tremendous advantages over electronics... starting with the possibility of insanely high clock rates (think of the difference between microwaves and UV light!!!) Photonic signal pathes can be multiplexed, that is light pulses of countless frequencies can run down the same channel. Photonics are not at all limited to binary, or any other arbitrary base. Pick one you like... like decimal, and have a party. Photonics can perform massively parallel calculation inside photonic arrays. Those calculations can be used to control logic flow, and data organization, allowing a new hierarchy of computing which doesn't even exist in current solid state devices (i.e. self modifying, self optimizing hardware tuned to recursive operational analysis.)

        As for the whole waste heat conversation... Remember, in a photonic, the light passing through the device doesn't necessarily produce significant heat. Photons passing through a transparent medium don't interact with matter the same way electrons do... resistance to currents of light aren't anything like electrons in their ability to produce heat, that is, as long as the light passing through an optical gate doesn't fluoresce (re-emit light) in the far infrared, there is no reason to expect that gate to get warm. The only true source of light on the chip will be the clock (not exactly true considering pumps, and amplifiers, but the concept is operationally correct), and that doesn't need to be a high wattage source (a 5mw tuneable laser should more than sufficient as a clock source.) Photonics run cool!

        Comparing photonics to electronics is missing the whole point of why we want to do photonics in the first place... photonics rock!

        Genda Bendte

        "And then he said let there be light! And it was good!"
    • Re:Still binary.. (Score:5, Interesting)

      by Perl-Pusher ( 555592 ) on Wednesday February 11, 2004 @08:36PM (#8254881)
      Imagine the size and speed gains we would get if we could now have three or four states per bit.

      Three states have been around awhile it's called Tri-state Logic [labri.fr]. Gordon Moore gave an interview [pcmag.com] in PC Magazine. He discussed multi-state logic, but said it was a non issue. He said that neural networks were much more important breakthrough.

      • Respectfully... I distrust the discussion of "third base" from a computer geek :)
      • by taniwha ( 70410 ) on Wednesday February 11, 2004 @09:46PM (#8255356) Homepage Journal
        'tertiary' logic and 'tristate' have different meanings. Tristate is simply a way of making a gate not drive a wire - so that some other gate can without 'bus fights' - there are no gates there that can sense that the wire is not being driven.

        In fact the signal on such a wire will tend to hang around at about the level it was last driven for quite a while (the wire is a cap) untill it discharges or some other gate drives it.

        In fact internal wires that are genuinely tristate are considered evil in most chip deigns - a floating signal will tend to turn on both the transistors in the gate(s) being driven causing current to flow where it shouldn't (one should be on or the other not both) - chips with internal floating nodes can et into horrible lockupstate which cause thermal runnaway and chip death. Normally if you are using tristate circuits you have a resistor to pull the wire to a known value when not in use, a weak 'keeper' transistor, a protocol which makes sure that someone is always driving them or a combination (PCI is a great example where all the bus clients know whow's driving each wire at any time and when wires are released they are first driven to a safe keeper voltage and then released so a weak resistor can hold them)

    • Not really (Score:5, Informative)

      by Sycraft-fu ( 314770 ) on Wednesday February 11, 2004 @08:47PM (#8254973)
      Problem is to have three or four states, you need more complex circuity. Binary is simple and works well. A bit it a gate, a transistor. It's on or it's off, 1 or 0. Well if I want to represent four states, how do I do that? I guess I need to do it by voltage or amperage level. MEans I need a more complicated circut.

      Give you something of a parallel in another digital field:

      Digital CD audio is stored as 16-bits per sample, 44,100 samples per second. Well that means that to convert the digital data to analogue, which is what sound waves are, you need to change the output voltage of the state 44,100 times per second, and do it to a resolution of 65,536 different levels. Originally, D/A converters tried to do just that, and failed rather miserably. It was just all hell to build a circut that could do a good job of controling voltage that accurately that quick in that fashion.

      The answer, it turns out, came from computers and high current variable speed electric motors. Motors of that type are controlled using what is known as pulse wave modulation. Their power source is either all the way on, or all the way off, binary in other words. It pulses at a high rate of speed. What you do is the faster you want the motor to go, the more on pulses you have. Works great, you have a simple design that provides a fine level of speed control. Only down side is the motor whines at the frequency of the pulse.

      Now this was applied to audio as well. What you do is convert the PCM data on the CD to a much higher frequency 1-bit PWM stream. That then controls the analogue voltage. It ends up working great, so good in fact that sony has a new system called Sony Direct Stream Digital that just takes and stores the PWM data directly. This type of converter is called a Delta-Sigma D/A converter and is basically the only kind used any more. You may CD consumer equipemnt, espically older stuff (Sony Discmans did it a lot), occasionaly advertise it as "1-bit D/A".

      Binary systems are just simpler to implement in electronics, hence we do. It is at higher levels that they start representing data with multiple states.
      • Re:Not really (Score:3, Interesting)

        by volsung ( 378 )
        Incidentally, this was the trick used on that nifty TI graphing calculator hack which played "music" out the link port. The link port is just a digital I/O on the bottom of the calc, but someone figured out how to toggle it on and off in machine code to use it just like a "1-bit D/A". Plug some headphones in (with appropriate adapter) and you heard some really poor quality Green Day song. The frequency wasn't nearly high to be more than a proof of concept, but it was cool nevertheless.
    • Re:Still binary.. (Score:5, Insightful)

      by femto ( 459605 ) on Wednesday February 11, 2004 @08:52PM (#8255006) Homepage
      Imagine the size and speed gains we would get if we could have lots of states per bit. Ummm..., I've just reinvented the analog computer...

      I think you will find the whole point of binary is that the increased noise margins of having two states means the speed can generally be increased in a way that more than makes up for the reduced information capacity of two states, compared to multiple states. (Multi-level memory cells are actually low speed / duty cycle devices.)

      A 'bit' is a mathematical abstraction. In reality, a 'bit' is an analog pulse who's signal-to-noise ratio is just enough to discern two states (read up on eye diagrams).

    • So instead of being "yes"/"no", bits should offer more possibilities, like "maybe", "can i call a friend?" and "CowboyNeal"?
  • NYT not necessary (Score:4, Informative)

    by djupedal ( 584558 ) on Wednesday February 11, 2004 @08:19PM (#8254702)
    SAN JOSE, California (AP) -- In an advance that could inexpensively speed up corporate data centers and eventually personal computers, researchers used everyday silicon to build a device that converts data into light beams.

    Light-based communications has until now largely been the realm of large telecom companies and long-haul fiber-optic networks because of the expense of the exotic materials required to harness photons, the basic building block of light.

    Now, researchers at Intel Corp. say their results with silicon promise to reduce the cost of photonics by introducing a well-known substance that's more readily available.

    In the study, published in Thursday's journal Nature, the Intel researchers reported encoding 1 billion bits of data per second, 50 times faster than previous silicon experiments. They said they could achieve rates of up to 10 billion bits per second within months.

    "This is a significant step toward building optical devices that move data around inside a computer at the speed of light," said Pat Gelsinger, Intel's chief technology officer.

    Intel believes the finding could have profound implications for the links between servers in corporate data centers. Eventually, the technology could find its way into personal computers and even consumer electronics.

    "It is the kind of breakthrough that ripples across an industry over time, enabling other new devices and applications," Gelsinger said. "It could help make the Internet run faster, build much faster high-performance computers and enable high bandwidth applications like ultra-high-definition displays or vision recognition systems."

    Unlike electrons that flow through copper connections common today, the photons in light are not susceptible to data-slowing interference and can travel farther.

    The Intel researchers built a device called a modulator, which switches light into patterns that translate into the ones and zeros of the digital world.

    A light beam was split into two as it passed through the silicon, which has tiny transistor-like devices that alter light. When the beams are recombined and exit the silicon, the light goes on and off at a frequency of 1 gigahertz, or a billion times a second.

    Infrared light is used because it can pass through silicon.

    "Just as Superman's X-ray vision allows him to see through walls, if you had infrared vision, you could see through silicon," said Mario Paniccia, a study author and director of Intel's silicon photonics research. "This makes it possible to route light in silicon, and it is the same wavelength typically used for optical communications."

    The researchers expect to be able to increase the frequency to 10 gigahertz, making the technology commercially viable, said Victor Krutul, senior manager of Intel's silicon photonics technology strategy.

    "This implies that the economies of scale that we have seen for the electronics industry could one day apply to the photonics industry," Graham T. Reed, a professor of optoelectronics at the University of Surrey's Advanced Technology Institute, said in a commentary that accompanied the research paper.
  • damn universe.. (Score:4, Insightful)

    by molo ( 94384 ) on Wednesday February 11, 2004 @08:22PM (#8254727) Journal
    the barrier to building fundamentally new kinds of computers not limited by physical distance should become a reality, experts say

    I think the universe might disagree. The speed of light is a limiting factor. The speed of electrons/transistor switching is what we're hitting now. (takes more than one clock cycle for a signal to propogate accross a chip) We will exchange that for a the light/photothingie switching speed that will be higher. This is not limitless.

    Also, not limited by physical distance? Are these guys on crack? My Quake game is limited by physical distance. It takes 100ms to go across the country and back. Latency is the killer here.

    • I was wondering if they were talking about distances within the computer. Either on the chip, of with the buses.
    • I think the universe might disagree.

      That universe, thinks he's so smart...
    • Re:damn universe.. (Score:4, Interesting)

      by lkeagle ( 519176 ) on Wednesday February 11, 2004 @09:04PM (#8255090) Homepage
      Sorry, accidentally posted anonymously the first time:

      The limitation on physical distance in an electrical medium is dictated by its impedance, which dissipates the electrical energy in the form of heat. This creates an enormous problem of power loss, which increases linearly with the distance of the transmission line.

      An optical waveguide, such as fiber or the silicon waveguides mentioned in the article, see no such losses due to electrical impedance.

      Theoretically, as long as the parameters are met for photonic propagation, light will stay in the waveguide indefinitely. However, there are still losses due to imperfections and impurities in the medium itself, caused by microscopic deformities, bubbles, splices in the fiber, etc. There are also some losses dues to quantum effects, which we see in the form of 'evanescent' waves that tunnel outside of the boundaries of the waveguide.

      What you really want to be asking is what is the transmissive and absorbtive properties for the silicon medium they use for the particular wavelength(s) of light that they are developing the technology with. If you know that, then combined with the effects above you can get a decent estimate of the power dissipation of the system for a given photon source.

      My feeling, without performing the calculations, is that you will be pleasantly surprised at how little energy will be dissipated in the form of heat.

    • Re:damn universe.. (Score:3, Interesting)

      by pz ( 113803 )
      Indeed. Remember that electricity moves at the speed of light. (pause) Yes, the speed of light. (pause) Yes. Not the speed of light in a vacuum, the speed of light in the transmission medium in question. When this is wires on a PC board or traces on a chip, the capacitance and inductance of the wires -- which form the transmission medium -- slow down the photons which mediate the field propagation (at least that's one way of looking at it). For example, the speed of light in a coax cable is slower t
    • Re:damn universe.. (Score:4, Informative)

      by Tailhook ( 98486 ) on Wednesday February 11, 2004 @10:25PM (#8255562)
      My Quake game is limited by physical distance. It takes 100ms to go across the country and back. Latency is the killer here.

      Rough, napkin quality calculations here...

      m = miles to server = 2000 (round figure for "across the country")
      c = miles covered by light in 1 sec

      2m/c = 21ms round trip time

      100ms - 21ms = time lost to switching hardware, mostly, given that (in my experience) a simple ICMP ping will usually show very similar results, we probably can't attribute it to server processing time.

      So, as you can see, there is plenty of room for improvement. Faster/less switching between you and them means less latency. If you have 1/50 second latency, events are reported to you in the time it takes a good CRT to refresh twice.

      Light is fast.
  • by Neo-Rio-101 ( 700494 ) on Wednesday February 11, 2004 @08:22PM (#8254728)
    "We're trying to siliconize photonics"

    We're trying to morph bleeding-edge content
    We're trying to facilitate sticky experiences
    We're trying to productize user-centric convergence
    We're trying to empower extensible networks
    We're trying to synthesize revolutionary ROI
    We're trying to matrix e-business technologies
    We're trying to cultivate impactful relationships

    ....yada yada yada...

    ...Look, how fast will the thing go, and will I end up starting a fire in my PC from overheat?
  • by l0ungeb0y ( 442022 ) on Wednesday February 11, 2004 @08:22PM (#8254731) Homepage Journal
    Photonics == lasers
    So this technology should also revolutionize the mod scene and therefore dramatically effect Slashdot's front page.
    I wonder how many kids will accidentally burn their eyes out looking into the light?
  • by Anonymous Coward on Wednesday February 11, 2004 @08:22PM (#8254734)
    ... not a chip you can 'overclock'. Basically, it is a way to send LOTS of data over a fiber line. They use an example of picking any seat in a stadium and having a dynamic TV show you that seat based on an angle you sit to the TV. So unless the data is pre-processed, this is NOT a new CPU.

    "The device Intel has built is the prototype of a high-speed silicon optical modulator that the company has now pushed above two billion bits per second at a lab near its headquarters in Santa Clara, Calif. The modulator makes it possible to switch off and on a tiny laser beam and direct it into an ultrathin glass fiber. Although the technical report in Nature focuses on the modulator, which is only one component of a networking system, Intel plans on demonstrating a working system transmitting a movie in high-definition television over a five-mile coil of fiberoptic cable next week at its annual Intel Developer Forum in San Francisco."

  • Moore's Law (Score:3, Funny)

    by Anonymous Coward on Wednesday February 11, 2004 @08:23PM (#8254740)
    ...or is this (Moore's Law)^2 ?

    Better yet...will this be meazured in LHz (Ludicrous-hertz)?
  • by Carnildo ( 712617 ) on Wednesday February 11, 2004 @08:24PM (#8254755) Homepage Journal
    ...building fundamentally new kinds of computers not limited by physical distance should become a reality...

    So they've broken the lightspeed barrier? Amazing!
  • Photonics (Score:5, Interesting)

    by Anonymous Coward on Wednesday February 11, 2004 @08:24PM (#8254757)
    ... is the coolest technology you've never heard of.

    For some reason, buried among a zillion dog-eared back issues of "People" and "Sports Illustrated" at the Seattle's Best Coffee shop at the corner of Central and Kirkland Way in Kirkland, Washington, somebody left a copy of Photonics Spectra [photonics.com] in the magazine rack. I'm an electronics geek who had never heard of the field, and I probably spent three hours and two quad-damage lattes poring over that magazine. Fucking amazing stuff. Spend some time at the photonics.com website if you don't believe me.

    Seriously, photonics looks like it might be the Next Big Thing.
  • monopolizing (Score:4, Interesting)

    by segment ( 695309 ) <silNO@SPAMpolitrix.org> on Wednesday February 11, 2004 @08:25PM (#8254760) Homepage Journal
    With this breakthrough, Intel researchers said, they have shown that it should be possible to build optical fiber communications systems using Intel's conventional chipmaking process

    Great now we'll only have to buy from two companies in the future Intel and Microsoft.

    Seriously though, when I hear some chip news, and how it's the 'next best thing' I kind of wonder how much is just marketing hype. So far I heard of terabyte chips... Coming Soon!!!... Faster chipset will do... and so on. Yet on the market you see none. According to most companies capabilities (providing it's not just hype), from what I gather, they have a chipset in the works that can fly you to the moon, wash your car, bone your partner, and have you back in time for work the next morning. However, these companies have to make as much money as they possibly can selling you their fourth, third, and second generation chips for the next few years.

  • by Sebastopol ( 189276 ) on Wednesday February 11, 2004 @08:25PM (#8254766) Homepage
    Given the current press reports from the White House and David Kay, how do we know we can trust this intel?
  • by Orthogonal Jones ( 633685 ) on Wednesday February 11, 2004 @08:26PM (#8254769)

    Disclaimer: I am a Ph.D. in fiber optic physics

    This is a 2 Gb/s modulator, whereas III-V semiconductor modulators above 40 Gb/s are commericially available.

    A modulator by itself is nothing new, and not the whole story. You need optical waveguides with bending radii much smaller than currently available for routing, and optical logic gates which are an even worse problem.

    The article doesn't describe the technology -- is it electroabsorption? Mach-Zehnder?

    Nevertheless, a small and fast silicon modulator has obvious commercial value, even if it isn't the greatest thing since sliced bread.

    • by mamba-mamba ( 445365 ) on Wednesday February 11, 2004 @08:45PM (#8254956)
      Right. The article implies that they found a way to make modulators that doesn't involve any fancy process steps or exotic substrates. This could open the door to modulators built-in to processors or chipsets, instead of relying on expensive, power-hungry external modulators.

      It's a bit like when they figured out how to build serializers in CMOS. Suddenly there are serializers everywhere that don't need a separate physical layer device. This is almost like the next step.

      Also, this could mean that things like optical fibre-channel and possibly 10 gigabit ethernet will be cheaper. Who knows.


    • by DeeKayWon ( 155842 ) on Wednesday February 11, 2004 @09:34PM (#8255268)
      This is not really a reply to the parent. This is meant to help explain why silicon is so tough to make optoelectronics with.

      The electrons in materials have many different energies - in metals, the possible energies are so tightly spaced that you have what looks like a single continuous band of energy levels. With semiconductors, you have two effectively continuous bands with an energy gap between them. For silicon, for example, the gap is 1.1eV. The higher energy band is called the conduction band (CB) while the lower is called the valence band (VB).

      When an electron in the CB falls into the VB (direct recombination), it loses energy which is emitted in the form of heat (phonons, aka lattice vibrations) or light (a photon). Electrons in the CB prefer to hang around in the lowest energy states of the CB, so that's where they usually fall from. The unoccupied states of the VB tend to be the highest energy states in that band, so that's where electrons fall to.

      Now, the problem: momentum conservation. An electron can only directly fall from the CB to the VB and emit a photon if momentum is conserved, and photon momentum is negligible compared to that of the electron. So the momenta of the source and destination states must be pretty close, and for there to be an appreciable amount of direct recombination, the momenta of the CB's lowest-energy states must correspond to the VB's highest energy states, and this happens in direct bandgap semiconductors.

      Si, unfortunately, is an indirect bandgap semiconductor. The preferred source and destination states don't line up on energy-momentum diagram.

      Now, that doesn't mean it's impossible to get light out of silicon, just more difficult. You need what are called recombination centres, which are defects which the electrons can get trapped in (emitting phonons in the process and changing momentum) and from there drop to the VB (indirect recombination). For example, Al-doped SiC can be used to make blue LEDs, but their efficiency is measured in fractions of a percent.

      III-V semiconductors are made of elements in the III and V groups in the periodic table, GaAs being the most well-known. They tend to be direct bandgap semiconductors, and so they are far more conducive to direct recombination and are easier to make optoelectronics out of.
    • by Hal-9001 ( 43188 ) on Thursday February 12, 2004 @01:40AM (#8255703) Homepage Journal
      The article doesn't describe the technology -- is it electroabsorption? Mach-Zehnder?
      Thanks to my university's online subscription, I was able to read the actual Nature article. The device is a phase modulator and it actually uses the free carrier plasma dispersion effect (not a classical electrooptic field effect like the Pockels effect) to modulate the refractive index of silicon. They achieve this effect using a MOS capacitor instead of carrier injection or depletion in a p-i-n device. By doing so, they've boosted the modulation speed from 20 Mbps to 1 Gbps. To convert the phase modulation to amplitude modulation, they fabricate the device in one arm of a waveguide Mach-Zender. Admittedly, it's not a great advance in overall bitrate, but it is a significant step forward for silicon as a photonic material.
  • by Stonent1 ( 594886 ) <stonent@sto[ ]t. ... t ['nen' in gap]> on Wednesday February 11, 2004 @08:30PM (#8254810) Journal
    So now the only barrier is the speed of light? Or do I need a nice warp core sitting in my living room to overclock?
  • by MacGabhain ( 198888 ) on Wednesday February 11, 2004 @08:30PM (#8254824)
    Propogation of light through fiber is only about 50% faster than propogation of electrons through a copper conductor. The comments about making distance irrelevant seems completely unrelated to what's been accomplished.

    What Intel seems to be discussing is much faster transmission rates though the line (ie: bandwidth), which in itself is a really good thing if it's being done at reasonable heat and power levels.

    • Light through fiber doesn't allow other signals to couple in through inductively, capacitively, or through RF (assuming the fiber has good insulation around it that blocks light coming in). So you can run buses a lot longer. Usually capacitance and crosstalk become limiting on bus length.

      The speed of light is relevent too, but usually only for the number of wait states you need at the start of a bus transaction.
    • by qedigital ( 545151 ) on Wednesday February 11, 2004 @09:01PM (#8255073) Homepage

      It is a common misconception that electrons move quickly through conductors. This, however, is not the case. When an electric field is applied to a conductor (e.g. from a battery), the random motion of the electrons in the material gain a small drift velocity. In copper (a relatively good conductor), this drift velocity is on the order of 10^-5 m/s to 10^-4 m/s (much less than c=3E8 m/s). The reason that conductors work the way they do is that the information is carried by the electric field rather than the individual electrons. A good analogy here is to think of a tube filled with ball bearings. Stuff one more bearing in the tube at one end and one pops out of the other "instantaneously". While the inserted bearing didn't travel the distance, it did have an effect at the end of the tube.

      Another common error is raised by the parent post. Transmission rate and bandwidth are completely different concepts. The transmission rate refers to the number of bits of information that can be transmitted down a pipe without loss (i.e. the capacity). Bandwidth, on the other hand, is a frequency domain concept and refers instead to the range of frequencies that the pipe can support. While it is true that a system with greater bandwith usually has greater capacity, it is a gross generalization.

  • by joab_son_of_zeruiah ( 580903 ) <fdruseikis @ s c . r r . c om> on Wednesday February 11, 2004 @08:31PM (#8254834) Homepage
    fundamentally new kinds of computers not limited by physical distance should become a reality, experts say

    ... 186,000+/- miles per second. Enough delay to make TCP/IP "an issue" for satellite networks?

    I love generalization.

  • by G4from128k ( 686170 ) on Wednesday February 11, 2004 @08:32PM (#8254845)
    Its an interesting breakthrough, but only from the standpoint of manufacturing high speed optical interconnect systems using standard silicon as the substrate material. It would seem that the technology still relies on standard electronic computation, but has a convenient way to convert eletronic signals into photonic ones on a standard silicon chip (versus the more exotic materials currently used for optical modulators).

    Rather than create all-optical processors, this technology will be useful for building gigabit fiber interfaces directly into everyday silicon chips. I'd think that the next step for this stuff will be cheap fiber connections between peripherals and interal subsystems (Optical ATA anyone?) Then they will look to create optical traces that connect Intel processors, cache, RAM, I/O chips (if they can figure out how to mass-produce a optical fiber traces on a PCB).

    This breakthrough more of an interconnection technology than a computation technology.
  • by jaoswald ( 63789 ) on Wednesday February 11, 2004 @08:45PM (#8254952) Homepage
    Can you guys all shut up about Pentium and clockspeed for crying out loud?

    This is about optical networking using silicon as the semiconductor. Not about a CPU.

    Everyone who doesn't understand what an optical modulator is can go post on the latest SCO story. That is all.
  • Finally.... (Score:5, Funny)

    by vwjeff ( 709903 ) on Wednesday February 11, 2004 @08:47PM (#8254972)
    Computing at the speed of light. Oh, wait, bottlenecks. Damn you serial ATA Hard Drive!!!
  • by Crypto Gnome ( 651401 ) on Wednesday February 11, 2004 @09:30PM (#8255238) Homepage Journal
    After reading the article, it turns out that *all* this hoo-ha is about the fact that INtel has worked out how do do telecommunications level optical switching (read LED-LASER-RAPID-BLINKING) on a chip built using "normal" chip fabrication techniques.

    This is in no way about "faster CPUs" it's ALL about "now we can fabricate telecomms equipment using standard CPU techniques, so they'll be cheaper and therefore easier to put into devices".

    So you're not likely to be getting significantly faster PCs from this technology, though it *does* make more likely the chance of (one day) having a direct gigabit fiber port on your PDA (or digital camera/other-small-electronics-device)
  • HOP (Score:3, Funny)

    by forkboy ( 8644 ) on Wednesday February 11, 2004 @09:35PM (#8255275) Homepage
    Hooked on Photonics worked for me!
  • by Grave ( 8234 ) <awalbert88NO@SPAMhotmail.com> on Wednesday February 11, 2004 @09:51PM (#8255387)
    SAN FRANCISCO, Feb. 11 -- Intel scientists say that they have made silicon chips that can switch light like electricity, blurring the line between computing and communications and presenting a vision of the digital future that will allow computers themselves to span cities or even the entire globe.

    Great! I was getting so tired of my computer being only 5lbs and man-portable! I can't wait for these new planet-sized computers. Mine's going to be called the Death Star.
  • photonic clocking (Score:5, Interesting)

    by griffinp ( 611793 ) on Wednesday February 11, 2004 @09:56PM (#8255406)
    Having not read the paper, it's hard to say how great this works, but it's worth mentioning that optical microchip clocking may be a major development over the coming decade. As clock speeds get faster (4GHz anyone?), small variations called clock skew and jitter become critical difficulties. Basically, because the clock signal doesn't propagate in an exactly predictable amount of time, different chip parts end up out of sync. Because optical clocking would rely on waveguides, with faster transmission and using uncharged particles that don't pick up random electrical signals, sending clock signals via light waves could be very beneficial. Of course, this development only speaks of the sending end - the modulator - not the receiving end, but we can be sure that Intel and many others are hard at work developing this technology.
  • by euxneks ( 516538 ) on Thursday February 12, 2004 @03:08AM (#8256058)
    ...barrier to building fundamentally new kinds of computers not limited by physical distance should become a reality, experts say...

    I was under the impression that physical distance was always a limitation...? Which "experts" are saying this?
  • by Gr8Apes ( 679165 ) on Thursday February 12, 2004 @10:53AM (#8257819)

    AMD comes out with a nice 64 bit CPU, Intel takes their highest end 32bit CPU, repackages it for a desktop, at twice the price, and barely competes.

    AMD's 64 bit solution looks to beat the pants off of Itanium... Intel's statement that they're working on an x86 64 bit CPU says everything we need to know.

    Sun partners with AMD - smartest move they could have made, especially if they jointly develop the next generation of AMD CPUs. Can we say massively SMP processing added to a fast core?

Variables don't; constants aren't.