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Networking Science

All-Optical Networks: the Last Piece of the Puzzle 36

Esther Schindler writes "An MIT professor explains why "simple" ideas require hard science and how a gemstone might be the key to an optical network. As the story begins: 'For years, the dream of an all-optical network has lain somewhere between Star Wars and a paper cup and a string. Recent successful work on the creation of an optical diode is a virtual case study in both the physics and materials sciences challenges of trying to develop all-optical networks. It is also a significant step towards their final realization.' One answer may be... garnet. Yes, the January birthstone. 'The material that Ross and others in her field use is a synthetic, lab-grown garnet film. Similar to the natural mineral, often used as a gemstone, it is transparent in the infrared part of the spectrum. This makes synthetic garnet ideal for optical communications systems, which use the near infrared. Unlike natural garnet, it's also magnetic. ... While it works, it's too big and too labor intensive for use as a commercial integrated chip. For that, you need to grow garnet on silicon. The challenge that Ross's group overcame is that garnet doesn't grow on silicon.'"
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All-Optical Networks: the Last Piece of the Puzzle

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  • It's amazing how much upper education is a much more ethnically-integrated environment for the finest minds in our country around the globe, but a few days ago we were told all the chinese students are spies we should watch out for ( And yet, here we are, all excited about the work some bright chinese grad student accomplished. It bugs me, that story.. a sense we are isolating ourselves from the world and what

  • by Hentes ( 2461350 ) on Monday April 16, 2012 @05:43PM (#39704571)

    You also need a transistor for a logical circuit, and that's much harder.

    • Re: (Score:1, Informative)

      by Anonymous Coward

      Optical Transistors already exist. was the second result on Google behind Wikipedia.

      If you read the article, you'll see why diodes came last in this case - but then again, why read the article when you can just make uninformed comments?

    • by Anonymous Coward

      Yes, you can do more with transistors but you can do logic with diodes:

      • by Hentes ( 2461350 )

        Interesting, but these circuits also need a resistor, and they are just AND and OR gates, so not a complete logic.

        • by Anonymous Coward

          You can't invert (nand, nor, not, xor) with diodes. But and/or is enough for signal switching:
          X=(A and C) or (B and C')
          will switch X between A and B depending upon whether C or C' is high.

      • you can do logic with diodes:

        Not really, you can do SOME logical operations with them but to make a proper logic system you need devices that can invert signals (turn whatever you have chosen to represent a 1 into whatever you have chosen to represent a 0 and vice-versa) and devices that can boost signals (take a weaker incoming signal and produce a stronger output signal).

        Diode logic as described in the wikipedia article can only provide and/or and worse it will SERIOUSLY weaken the signal when one of those is followed by the other.


  • Wasn't this the plot of Michael Crichton's book, "Congo"? The lead researcher was even a woman named Ross, IIRC...

  • It's no neodymium or iron but a magnet will still pick up quite a bit of natural garnet.

  • by oren ( 78897 ) on Tuesday April 17, 2012 @01:33AM (#39707785)
    Hmmm... a material that passes light only in one direction, and can be turned on/off using a magnetic field. Optical networks aside, I wish it was available as a coating for windows. True one-way windows!
  • In the 1970s, magnetic bubble memory was expected to be the next big thing in nonvolatile data storage, and there were commercial products from Hitachi, Intel, Rockwell, and TI. Commercial bubble memory devices were fabricated using garnet films, though there was research into the use of other materials.

    Due to high cost, bubble memory was successful only in limited niches, so by the mid-1980s it was discontinued. Intel stopped development at the 4 Mbit level; I don't think the other vendors even pushed it that far. Late 1980s research results suggested the possibility of 64 Mbit devices. I suspect that the technology probably wouldn't have scaled much further anyhow.

    More recently, IBM has been working on "racetrack memory", which works similarly to magnetic bubble memory.

  • What?

    What the shit is a birthstone and how does this relate to optical networks?

    • by Klync ( 152475 ) on Tuesday April 17, 2012 @09:37AM (#39709559)
      Actually, I found that little tidbit amusing, and I was surprised to see that nobody else commented yet on the irony of a connection between January and an optical diode

      In ancient Roman religion and mythology, Janus is the god of beginnings and transitions,[1] thence also of gates, doors, doorways, endings and time. He is usually a two-faced god since he looks to the future and the past. The Romans dedicated the month of January to Janus. []

Life in the state of nature is solitary, poor, nasty, brutish, and short. - Thomas Hobbes, Leviathan