kevin@sun.uucp (Kevin Sheehan) (02/05/85)
I lost the original posting, but I remember an article in Scientific American and some papers by Harris Corp. on optical bistable devices. The principle employed amplitude sensitive materials to produce a non- linear response in the effective optical length of a cavity to produce cancellation/reinforcement. It led to some interesting models for logic, most of them parallel in nature. Another article explored the applications of cellular automatons to parallel processing, and implied optical (photonic) implementation. l & h, kev
callele@sask.UUCP (David Callele) (03/18/86)
<...>
^
| Do we still need this thing?
Some time ago, someone posted an article saying that someone was going to be
unveiling an optical computer in (I think) Hanover or Hamburg. Could someone
please repost the article or send it to me? Thanks a lot.
If anyone else has any references to optical computers, optical bistable devices
etc. I would appreciate them also. Thanks again.
David J. Callele
Dept. of Comp. Science
University of Saskatchewan
Saskatoon, Saskatchewan
Canada, S7N 0W0miles@vax135.UUCP (Miles Murdocca) (03/19/86)
>>Some time ago, someone posted an article saying that someone was going to be >>unveiling an optical computer in (I think) Hanover or Hamburg. Could someone >>please repost the article or send it to me? Thanks a lot. >>If anyone else has any references to optical computers, optical bistable devices >>etc. I would appreciate them also. Thanks again. Here it is: >Path: vax135!houxm!whuxl!whuxlm!akgua!gatech!seismo!cmcl2!phri!roy >Message-ID: <2258@phri.UUCP> >Date: Thu, 27-Feb-86 19:29:50 EST >Reply-To: roy@phri.UUCP (Roy Smith) > About a year ago (I think) there was a smattering of speculation >about optical computers in this newsgroup. Well, the following just >caught my eye. Don't ask me for more details, you now know as much about >it as I do. Quoting from "Digital Design", February 1986 (Copyright 1986 >by Morgan-Grampian Publishing Company): > OPTICAL PROCESSOR MODEL -- A functional model of an optical > processor will debut at March's Hanover Fair in West Germany. > Offering potential picosecond speeds for parallel architectures, > the model results from work carried out by the European Joint > Optical Bistability project. >-- >Roy Smith, {allegra,philabs}!phri!roy >System Administrator, Public Health Research Institute >455 First Avenue, New York, NY 10016 I wouldn't rush out to Hanover to see a picosecond computer because the picosecond machine does not exist. The devices are interference filters made with ZnSe that operate at 100's of microseconds. The project is under the direction of S Desmond Smith, a professor of physics at Heriot-Watt. He never made the claim that his computer runs at picoseconds but somehow the press must have picked up the phrase "potential picosecond speeds". A stepper motor is used to move the beam to different parts of the device because the intensity of the beam destroys the material. Here at AT&T Bell Labs, we have an effort that has much more promise. We already have samples of optical devices that run at 30ns (see reference 4 below) and another device waiting in the wings that operates at 70ps (see reference 3). Both of these devices (the Multiple Quantum Well SEED and the nonlinear Fabry-Perot etalon) are grown with molecular beam epitaxy (MBE) which is an expensive process that few companies can afford. I can't give particulars about the state of the devices or the method of processing beyond what you will find in the published articles because of proprietary interest. You will find references 1 and 2 of particular interest because they go over the computing aspects of optical computing. My full-time job at AT&T Bell Laboratories is to find methodologies for programming optical computers, so I would be glad to trade ideas with anyone who has an interest. I can only talk about what material has been released for publication outside of AT&T. Note that there are only a few groups who are working on *digital* optics. Much of the work on optical computing has been in the *analog* domain. Miles Murdocca, 4G-538, AT&T Bell Laboratories, Crawfords Corner Rd, Holmdel, NJ, 07733, (201) 949-2504, ...{ihnp4}!vax135!miles 1) A. Huang, "Parallel Algorithms for Optical Digital Computers", 10th International Optical Computing Conference, IEEE catalog number 83CH1880-4, pp13-17. 2) A. Huang, "Architectural Considerations in the Design of an Optical Digital COmputer", Proc. IEEE, July 1984, pp780-786. 3) H.M. Gibbs et al, "Room temperature exitonic optical bistability in a GaAs-GaAlAs superlattice etalon", Appl. Phys. Lett., vol 41 no. 3, pp221-222, Aug. 1982. 4) D.A.B. Miller et al, "A novel hybrid optically bistable switch: the Quantum Well Self Elecrto-optic Effect Device", Applied Physics Letters, vol 45, July 1, 1984 pp13-15.