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A Look at Photonic Clocking
zymano writes "In an article on the Electronic Engineering Times site James Siepmann shares a few thoughts about Photonic Clocking. Siepmann states: 'Copper interconnects are reaching their limit as data-transmission bandwidth and processor speed continue to rise. [..] Photonic clocking not only solves the limitations of electronic clocking, but also reduces jitter, skew, delay, crosstalk and power consumption while maintaining clock signal integrity for longer distances.'" Are Photonic Processors the next logical step, or will the almighty buck shuffle them aside because of cost?
Aren't there like 5 or 6 orders of magnitude between optical frequencies and current clock rates? And last I checked, copper waveguide does
just fine for at least 3 or 4 of those. So how is it that we are "reaching the limitations" of copper?
Nice thing about a pulse of light is that it can be made to reach lots of places at the same time, or nearly so. Just a normal burst of light from a point source has a spherical wavefront, but this can be modified by optics in various ways. Having designed plenty of really fast stuff and having had to deal with skew problems, I can see the advantadge, if real use can be made of it. I think it might even be possible on silicon, which would be required for quick adoption -- after all, the LSI only has to receive, the clock light source can be made of anything. Making a hybrid of course drives costs way up, though. but at current profit margins for fast cpu's this may not be much of a real issue.
dude i didn't know the autopr0n guy knew some EE. props to you. thought you were high-level cs guy. btw, whatever happened to your server.
I find it amusing that you are picking one part of a piece of technobabble, and ignoring the rest. If you were going to correct the technobabble:
* Neutronium may not even be physically possible, and certainly would be instantly highly explosive in Earth-conditions. It certainly wouldn't "alloy", and has nothing to do with the theoretical Dirac Sea.
* Zero-point energy is not related to processors
* You can "channel" photons, but not a "photonic current", which is at best a term to describe the amount of current that can be produced by receiving a stream of electromagnetic radiation.
* What would "plasma conduits" have to do with either light or current?
* There is no such thing as a "phase conducer"
The thing that makes technobabble amusing is that it's *wrong*. It's pseudoscientific. It's fake. If something was theoretically possible, and terms were used correctly, it wouldn't be technobabble.
You look beautiful! Incidentally, my favorite artist is Picasso.
I have a feeling that quantum computing will happen before photonic computing. That's just me though...
-illumina+us "I put on my robe and wizard hat..."
The reason you don't see asynchronous chips is that it's damn near impossible to guarantee that they work.
With standard clocked CPUs, you can draw a box around the chip, or part of it, and treat it like a black box. Signal in, signal out, clock: change any and all of these to guarantee/profile your behavior. That doesn't work on async design. There's no way you could test it all and have any confidence that you did it right.
Few years ago, I read the book "Asynchronous Circuit Design" by Chris J. Myers, in which it is explained the basics for designing digital asych logic by using special techniques and gaining advantages in power consumption and systems speed and, to stay on topic, no clock to be propagated through the silicin at all.
The real questions are:
- why these tecniques never gained importance (the first studies are from S.Unger in 1969)?
- what about the EDA industry?
-- See you, UncleScrooge