Xref: utzoo comp.arch:17325 sci.electronics:13054 sci.physics:13721 comp.lsi:1097 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!orion.oac.uci.edu!ucivax!ucla-cs!lanai.cs.ucla.edu!loving From: loving@lanai.cs.ucla.edu (Mike Loving) Newsgroups: comp.arch,sci.electronics,sci.physics,comp.lsi Subject: Re: Electro-optic bus Message-ID: <37232@shemp.CS.UCLA.EDU> Date: 24 Jul 90 16:45:20 GMT References: Sender: news@CS.UCLA.EDU Distribution: comp Organization: UCLA Computer Science Department Lines: 34 In article aglew@oberon.crhc.uiuc.edu (Andy Glew) writes: >A while back I posted about an electro-optic bus to comp.arch. It >generated a flurry of responses, but nobody provided the real data >that one correspondent rightly suggested would be critical to an >electro-optic bus. > I am hoping that sci.electronics or comp.lsi or sci.physics >readers may be able to fill in the gaps. (For these newsgroups the >original post is included at the end of this post). [some stuff removed] > >Any experience people have in timing discrete electro-optical systems >would be helpful, providing at least an upper bound. A while back I worked with Dr. Norm Matloff at UC Davis on optical data transmission in computers. It differed in one major respect from your scenario, no lasers on the chips. Instead a thin electo-optic film is coated onto the chip. This film will polarize light in different ways depending on the voltage applied across the film. By then running the light through polarizing filters, one gets intensity modulation. You then run the light into what is basically a sense amp with optical reception (reverse bias diode or photo transistor). In the stuff we were doing, with the process parameters we had, we could distinguish between ones and zeros reliably if we had greater than 1% difference in incoming intensities. This took about 10 nanoseconds, but in theory, you transfer the entire contents of a chip to another chip this way, you just have focus and alignment difficulties that need to be worked out. When I left there 2 years ago, the electro-optic films were still not quite good enough to do the polarization job. norm matloff = matloff@iris.ucdavis.edu for more info than I've got. Mike Loving loving@lanai.cs.ucla.edu