 begin forwarded text date wed NUMBER oct NUMBER NUMBER NUMBER NUMBER NUMBER from john s denker jsd monmouth com subject re optical analog computing sender jsd no domain spam to r a hettinga rah shipwright com cc digital bearer settlement list dbs philodox com cryptography URL r a hettinga wrote the first computer to crack enigma was optical the first synthetic aperture radar processor was optical but all these early successes were classified NUMBER to NUMBER projects and i probably know of less than half do these claims compute is this really a secret history or does this mean holography of am i just completely out of the loop NUMBER gimme a break this is remarkable for its lack of newsworthiness NUMBER bletchley park used optical sensors which were and still are the best way to read paper tape at high speed you can read about it in the standard accounts e g URL NUMBER for decades before that codebreakers were using optical computing in the form of superposed masks to find patterns you can read about it in kahn NUMBER people have been doing opto electronic computing for decades there s a lot more to it than just holography i get NUMBER NUMBER hits from URL optical info is a complex valued wave spatial frequency amplitude and phase it isn t right to make it sound like three numbers frequency amplitude and phase actually there are innumerable frequencies each of which has its own amplitude and phase lenses refractions and interference are the computational operators add copy multiply fft correlation convolution of NUMBERd and NUMBERd arrays and of course massively parallel by default and of course allows free space interconnects some things that are hard with wires are easy with light waves but most things that are easy with wires are hard with light waves here s a commercialized effort from israel a space integrating vector matric multiplier a b c laser NUMBER gate modulator spread over NUMBERd NUMBER teraflop equivalent for one multiply per nanosecond people were doing smaller versions of that in the NUMBERs unclassified example acousto optic spectrometer NUMBER gflops equivalent for NUMBER watts doing continuous ffts launched in NUMBER on a NUMBER year mission submillimeter wave observatory not ffts fts fourier transforms all you need for taking a d NUMBER fourier transform is a lens it s undergrad physics lab stuff i get NUMBER NUMBER hits from URL of course the rest of the talk is about the promise of moving from optoelectronic to all optical processors on all optical nets with optical encryption so on all optical no optoelectronics anywhere that s medicinal grade pure snake oil usp photons are well known for not interacting with each other it s hard to do computing without interactions end forwarded text r a hettinga mailto rah ibuc com the internet bearer underwriting corporation URL NUMBER farquhar street boston ma NUMBER usa however it may deserve respect for its usefulness and antiquity predicting the end of the world has not been found agreeable to experience edward gibbon decline and fall of the roman empire 