Wayne@OZ.AI.MIT.EDU.UUCP (11/20/87)
Regarding data transmission rates, perhaps we should be thinking about the possibilities of 1 terabit/sec, which is 2000 times greater (I think) than .5 gigabit/sec. That should provide enough ability to move copies of a global hypermedia advisor around the world with considerable ease. Here is an earlier posting to another list: Date: 5 Oct 1987 07:58 EDT (Mon) From: Wayne McGuire <Wayne@OZ.AI.MIT.EDU> Subject: LC's Per Minute %A James Gleick %T New Frontiers of Communication Lie in Test Superconductor Device %J The New York Times %D October 2, 1987 %P A1, A13 [A few excerpts from the article follow. This is not strictly nanotechnology, and probably everyone saw it, but the numbers are fairly astonishing, particularly the phrase about sending the complete contents of the Library of Congress in two minutes.] A small prototype device has shown that communications lines made from the new generation of superconductors can transmit data at speeds up to 100 times faster than today's state-of-the-art optical fiber networks, scientists said yesterday. Very short electrical pulses, measured in trillionths of a second, passed through the device without any detectable distortion, an impossibility with conventional metals. The report raises the prospect of transmission of electronic information--computer data, telephone conversations or television pictures--at extremely high speeds. A single superconducting transmission line could carry one trillion bits a second, the scientists said. This would be enough to support 15 million simultaneous conversations or, alternatively, to send the complete contents of the Library of Congress in two minutes. The device was made at Cornell University and tested at the Ultrafast Science Center of the University of Rochester by a team using lasers to measure the very short pulses, slicing time into extremely fine slivers. "It's a very exciting step forward, there's little doubt about it," said Alexis P. Malozemoff of the International Business Machines Corporation's research laboratory in Yorktown Heights, N.Y. "It's the key to communication within computers and to more distant points." .... In announcing their results, the scientists stressed that they were not predicting the demise of optical fibers, which are now only taking firm hold in the networks of long-distance telephone communication.... Nevertheless, Gerard Mourou, director of the Ultrafast Science Center, said a system using superconductors to transmit electrical pulses could be not only faster but ultimately simpler.... The tests at Rochester reflect scientists' continuing devotion to extending frontiers of the very short and the very fast. In high- speed electronics, particularly, the splitting of time into finer and finer units has become a central concern. The circuits of supercomputers typically transmit pulses in the range of a nanosecond, or a billionth of a second. Optical fibers work about 10 times faster. Research laboratories have produced switching devices, like transitors, that operate on scales of picoseconds, or trillionths of a second, so faster computers could depend on the ability to communicate at such speeds. In the ultrafast regime, just making measurements becomes a problem. The Rochester group used a dye laser capable of emitting pulses of 50 femtoseconds, or quadrillionths of a second, as its yardstick. Without superconductors, electricity could not compete with light on such time scales. "Now I think we're just scratching the surface," Dr. Mourou said.