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New Optical Chip Claims 8 Trillion Operations/sec.
Richard Finney writes "Lenslet is announcing
the 'World's First Commercial Optical Processor.'. Reuters has the story here. The Inquirer has a cool graphic here on it. The processor is specified to run at a speed of 8 Tera (8,000 Giga) operations per second, one thousand times faster than any known DSP. When Lenslet releases its Enlight processor in a matter of weeks, a unit using the technology will be 1.7 centimetres high and measure 15 by 15 centimetres."
There's a nice picture of the processor here
I studied this subject in depth and happen to know 6 six physics professors who agree with me on the subject. And I don't agree with a thing you've said.
To do anything at all with light, you need a material in with light beams can interact.
Light will interact in almost any medium. Many kinds of optical gates have already been created.
In this material, the speed at which electrons can change energy levels determine the speed.
I'm not even sure what you are talking about here. There are no signal carrying electrons in an optical fiber - that's the point. And if you meant photons instead of electrons, then the photons aren't changing energy levels. If you look back through your physics book, that would corrospond to changing color, and has nothing to do with optical computing. It is the absence or presence of light that determines the on or off state. Not the voltage, as in a regular processor.
In fact: the rise and fall time are determined by how fast you can (electronically) switch the light source on or off.
If you are using an isolated optical gate with electronic converters surrounding it yes. But that would be senseless and no one does it. Everyhing inside an opticl processor is connected by light signals. Each optical gate interacts with other optical gates optically. And as time goes on, the memory and bus of these systems will also become optical. Already, there are many physical processes that do not need any optical-electronic conversion : especially cpu bound operations that fit into the cache.
I don't beleive you have accurately grasped the concept of optical computing. If you have questions, please ask them. But don't assert your opinion as fact.
Slashdot Syndrome: the sudden, extreme urge to correct someone in order to validate one's self.
I'm not quite sure you understand what this processor is, and how it works. This is *NOT* like a Pentium with a faster clockspeed. This is a signal processing chip which, rather than really executing code, uses a series of optical filters to do massively expensive mathematical operations. This has the following set of properties:
The original poster was right, this IS the future, at least for now
Cheers,
Justin
Disclaimer: I'm one semester away from my bachelors in Physics
Seriously though, basically this chip can do very quickly what the SETI@Home software does on PCs. Fast fourier transforms and the like... Think about completing a calculation unit every 30 seconds instead of 8 hours and 40 minutes. That is the ball park. I wonder if the precision will be the same.
HAH!!! I found the post I lost in my browser cache!!! Now you can read and enjoy it.
Sorry if I came off snide. I didn't mean too. I took your comment to be snide and responded a little harshly. I will be much more civil.
Here's a better and longer explanation of what I said before.
With the present theory of computing (electronic and optical) you have a clock that drives the processor. Actions that take place such as moves, adds, rotates, and multiplies all take place because of an enabling clock pulse. There are bits that will be set on or off that are read and written at the clock pulse. For any digital computer, there must be on and off thresholds - above a certain threshold is on, and below a certain threshold is off - in between is not used and possibly an error.
With your degree, I'm sure you know all this.
Once a bit is set, that is a voltage applied or a light turned on, there is a certain amount of wait time until that signal propogates and can be read. The slope of the voltage vs time plot is rather shallow compared to a light intensity vs time plot. So in order to be reasonably sure that all bits your enabled have reached the threshold will take longer for an electronic signal than for an optical signal. This is why overclockers often increase the voltage on their cpu's, to decrease the time it takes for the signal to reach the threshold value. However, since the intensity of light increases much faster (the packet is tigher) the clock can be set at a MUCH faster rate and still maintain good assurance that all signals have reached their threshold value.
Hopefully this better explains what I said before. You can only imagine if I had tried to type that all into my original post!
Slashdot Syndrome: the sudden, extreme urge to correct someone in order to validate one's self.
They used to use regular electronic circuits to solve differential equations and similar problems too. They didn't get an exact solution, but they got a usable value. I think that's what you're talking about here.
:)
You're talking about old analog electronic computers... yeah those weren't very precise (one of the reasons they are no longer used).
What I'm talking about is a little different. Those electronic ciruits would solve differential equations in the time domain (requiring a bit of time to compute) whereas these optical processors process information in the frequency domain (almost instantly, the bottlneck is as you say how fast they can moduate the light from an electronic signal).
Frequency domain computing is fundamentally different from the time domain computing in that in time domain analog computers, tiny errors accumulate very rapidly. For instance, an operational amplifier that is used to perform an integration will have a small bias current which will slowly charge the integrating capactor(s), requiring the integration to be rezeroed every so often (at least every few seconds, if not many times a second). In frequency domain computation, the error is not accumulative like that. There is error, and it does add up, but its pretty much orthogonal (the error is spread throughout the frequency space, rather than adding up towards the end of the time space in a time domain computer).
A really great article I found (this is the one I originally read back in 2001) is here. Anyone interested in the more technical side of the processor should read it. It explains why the processing is so fast (because it's essentially parallel rather than serial, along with being based on photons rather than electrons).
That's where I got most of my information from, along with my optics and mathematical physics classes
Cheers,
Justin
Disclaimer: I'm still a semester away from my BS in physics
You can build both digital and analog computers from analog components. Indeed, aside from "ideal switches", I'd argue that most circuit components are analog. The poster to which you responded is correct -- a system built around discrete levels selected from a continuous domain is considered digital. A system built around continuous levels is considered analog.
So, if you build a computer around 4-level signaling, it'd still be digital. Each signal corresponds to a "digit," likely valued 0 thru 3. If you built a differential-equation analyser out of op-amps, resistors, capacitors and inductors to represent the derivatives/integrals in your system of equations, and operated it within the linear region of the op-amps, you'd have an analog computer. Those aren't very popular anymore, nor have they been for some time.
The options you suggested a couple posts up are all variants of digital signaling. The first one is binary signaling. The second one is discrete amplitude modulation. The third one is multi-frequency discrete amplitude modulation.
The real question is, can you build large numbers of sufficiently small gates for a given signaling method? Additionally, do those gates aggregate into computing structures we know how to use effectively?
Related side topic: 3-valued logic (ternary computing) likely won't take off until its proponents have good answers for both questions. Something tells me the circuits and the gates are the smaller of the two problems. The change in programming paradigm is too big.
--JoeProgram Intellivision!