New Optical DSPs With Tera-ops Performance

GFD writes: "The EETimes has a story about a new class of hybrid digital/optical signal processors that are programmable and offer tera-ops performance potential for relatively low cost and power requirements. No fundamental breakthroughs but rather a very slick use of existing optical networking components to create a programmable optical processor that looks to the rest of the world like a single chip digital signal processor. Elegant and impressive if they can deliver."

Comments

Their tera-ops are a little different

[mmacdona86]

since they are not actually processing the signal digitally. They are slickly converting it to a light signal, doing the heavy lifting with optical elements, which is essentially analog processing, and then converting it back to a digital signal. A real valuable short cut for those applications where you can translate what needs to be done to optical elements, but not anything like a general-purpose tera-ops digital computer.

[summary] Fast FFTs, DCTs, etc.

[grmoc]

Basically, for those of you too impatient to read the article, it works by using VSCELs (lasers) through conventional optics, and into a high-speed collector. The lasers can work at up to 1 Ghz, and the processing is done (it seems) in analog by the optics. Acquisition of the date is performed by the collector, which operates at 10 Ghz.

The theory is that optics can perform FFTs, DCTs, etc for you at the speed of light, and there are many applications that need these operatons done. Any other processing, correlation, etc would be done by conventional, low-performance DSPs.

They also say that their current model works at 20 T ops/sec at 20 watts, and list what would be required of typical DSPs, etc down to ASICS.

Seems promising, but it is still a long way away from a nice optical CPU.

Re:Optical FFT==Digital FFT ??

[MarkusQ]

I'm not sure that an optical transform is the same as a digital transform, or that they can be used to do the same thing. Can their optical FFT/digital encoding produce the same bits during JPEG encoding as a digital FFT/digital encoding JPEG encoder? This is crucial for image/video compression algorithms.

They are the same, in theory (in practice the tolerance of your components limits you to only a few digits of accuracy). The basic (and very generic) relationship is:

RW: Some real-world, physical process

OB: An observational model of RW

AN: An analytic model of OB

DI: A digital implementation of AN

AI: An analog implementation of AN, sometimes even based on RW.

The wonder of science is that many RW have the same OB, and many OB have the same AN (in both cases allowing for some paramiterization). While all of these can "implement the same function" they will have very different time/space/energy/cost/etc profiles. Digital, in particular, givers you greater precision and flexibility, but at a rather high cost in speed, size, and energy usage.

Up until faily recently (say, the last twenty to fifty years) the DI's were mostly done by hand. The only reason to do them was to get those extra digits, mostly for designers of the AIs (such as tube amplifiers and anti-aircraft guns) or to produce tables for use "in the field".

-- MarkusQ