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IBM Slows the Speed of Light
dptalia writes "According to an article on ZDNet, IBM has come up with a way to slow light to 1/300 of its normal speed. While this has been done in laboratories before, IBM has found out how to do this using standard materials, which opens the possibility of mass production. This means that the dream of having optical based CPUs may be closer than previously thought." From the article: "When the optical conversion might start to occur is a matter of speculation. Luxtera has said it will start to commercially produce products in 2007. The computer industry, however, tends to move slowly when it comes to major overhauls of computer architecture. Several components will have to be developed before photons can replace electrons inside computers. A paper providing details on the chip will run in Nature on Wednesday."
Joke aside, it's always been a variable. It changes depending on the medium it's traveling through. 'c' is just the speed of light in a vacuum.
but yes, there's a link. Your full-text access may vary.
Don't blame me; I'm never given mod points.
It allows you to build chips using light, at speeds for which we can reasonably design things, and interface them with things at small fractions of C. The benefit to the optical chip is power and heat, which means you can pack more chips in, which means you can make a faster computer.
I want to delete my account but Slashdot doesn't allow it.
Every Pratchett fan knows that light slows down if you apply a strong Magical field...
Light thinks it travels faster than anything but it's wrong. No matter how fast light travels it finds the darkness has always got there first, and is waiting for it.
- Reaper Man
http://science.slashdot.org/article.pl?sid=05/08/2 0/1440228&from=rss
There you go.
The higher the dispersion, the lower the practical bandwidth of the device.
Two wrongs don't make a right, but three lefts do.
The latest Nature podcast has an interview with one of the researchers working on this: http://www.nature.com/nature/podcast/index.html
Step 1: Pass light through any medium which is not a complete vacuum.
That's it!
There are multiple uses for a slowed signal; you can combine it with the un-delayed
signal and make filters, like is done with SAW filters (but those use surface acoustic waves,
and are not silicon-compatible). You can also make some kinds of shift register
VERY simply by sending the signal out into the delay and picking it up when you
need it. And a delay of a clock signal often makes a computer more reliable (designing
high speed compute devices, this is OFTEN a vital consideration).
The split/multiple delay/combine scheme for (for instance) radio signals is
a very powerful tool, and is why a complicated-looking antenna can work
so well. And, why a rabbit-ear antenna can take a lot of tweaking to
get your idiotbox to receive Red Green.
For major processing of data, it was common practice in the old days to tweak the
interconnect wiring to make the correct time delay. Seymour Cray reported (of the
Cray-1 supercomputer) that the interconnect in the central core of the computer
was hand-wired by (slender women) assemblers who used cut-to-measure lengths of
twisted pair, so that all the signals had the appropriate settling time before the clock
arrived and latched the data. The computer was a cylindrical hole with draped wiring
all over its interior, with spokes out that housed the cooled ECL logic modules.
To keep the Cray quick, the cylindrical core was as small as feasible. The assemblers
knew a LOT of the common computer language of their profession, i.e. profanity.