http://www.wired.com/news/technology/0,1282,50779,00.html By Mark K. Anderson 2:00 a.m. March 18, 2002 PST the idea of carrying phone conversations with light may date back to 1880, but its implementation took an entire century. It was only in the 1980s that fiber optic channels were first integrated into commercial phone networks. In the intervening years, much has stayed the same -- scientists and engineers still want to cram more and more zeroes and ones into those familiar hair-thin wires of glass. But major advancements appear to be on the way. Next week, Anaheim, California, will host about 25,000 researchers as they gather for the nation's leading fiber optics conference, the Optical Fiber Communications Conference and Exhibit. One of the more intriguing ideas to be presented involves using chaotic behavior across fiber networks as a method of encryption. According to Jia-ming Liu, professor of electrical engineering at UCLA, the emerging field of chaotic communications offers new crypto applications in both optical and wireless systems. "I didn't invent this concept," he said. "But the entire field of chaotic communication is pretty new." His system, he said, starts with a laser that sends part of its beam into photo detectors which produce electrical signal that feed back to help power the laser. The resulting circuit behaves erratically -- something like the feedback you hear at a concert when the performer wanders too close to his stack of amps. Liu has found that if he picks his lasers carefully, he can set up two such nonlinear (chaotic) circuits whose feedback behavior is the same. Thus, if you have a message that needs to get from Albuquerque to Boston without being snooped on, you place a laser in each city. After the two lasers have been synchronized over an open channel, you add your message signal on top of the sending chaotic laser. And once the signal reaches Boston, you use the Boston laser to subtract off the chaos -- and to get the original message. "Any eavesdropper who tried to tap your message would just receive noise -- akin to listening to static instead of the radio," he said. On Thursday, Liu will report that his team has transmitted messages using this chaotic crypto method at the benchmark speed of 2.5 Gbps -- also called the OC-48 level. In fact, this speed is comparable to the rate that much non-encrypted, long-distance telephone and Internet traffic travels at today. "Today, most of the 'long-haul' traffic is either 2.5 or 10 gigabits per second," said Ivan Kaminow, former senior science advisor at the Optical Society of America. "A lot of research is now exploring 40 gigabits per second." Indeed, one paper to be presented by a group from Agere Systems -- will be reporting a record-setting fiber optic transmission rate of 3.2 Tbps (trillion bits [terabits] per second). Of course, fiber isn't the only potential bottleneck in the system. Bishwaroop Ganguly of MIT is working on his PhD, examining the interaction between the optical and the old-fashioned electronic components in a network. On Wednesday, he'll be presenting work that offers a new, more integrated model for conducting network traffic with both optical and electronic signals. Such a system, he said, could enable a best-of-both-worlds Internet -- in which the Net itself would intelligently switch between using electronic switching systems for brief packets of data, such as Web pages, while optical switches would handle the bigger chunks such as MP3s or movie downloads. "We're looking at more of a symbiotic relationship between electronic sub-systems and optical sub-systems, where the electronics handle what they're good at -- which is small transactions," he said. "So consider a Web page. You wouldn't want to set up an optical connection for each JPEG. But if you're transferring files from one workstation to another, it would be nice if that could go all optically and bypass the electronic routers." Still, with all the applied and basic science being presented in Anaheim, one basic question is still very much up in the air: Will users see fiber optic lines coming into their home anytime soon? Ganguly said his system is being designed mostly for businesses. But he also said that it's a truism of the Internet that as bandwidth increases for individual users, new applications always emerge to fill it. "The point is there are existing applications," he said. "But there's another paradigm here too: Build it and they will come." - ISN is currently hosted by Attrition.org To unsubscribe email majordomoat_private with 'unsubscribe isn' in the BODY of the mail.
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