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The field of optical computing faded into relative obscurity, but it was revived in 1986 by a breakthrough at AT&T Bell Labs. Research scientist David Miller developed the world's tiniest optical switch, a thin chip that in its latest version measures no more than 10 micrometers (0.00004 in.) on a side. Made of advanced synthetic materials, the device can turn on and off a billion times a second without overheating.
Miller's switches became the building blocks for Huang's optical processor, which took five years to develop. His team finished construction around Christmas but did not get the machine to work until last month. The device is far cruder than even the most basic computers: it has no permanent memory, and the only function it can perform is counting simple numbers. Just a small fraction of the thousands of switches are connected. Nonetheless, Huang insists, the machine proves that his principle works. He thinks computer makers will soon replace wiring inside their machines with optical circuits. By 1995, he contends, some 30% of supercomputers will use optical interconnections.
Huang has not convinced everyone, however. Says one scientist: "Huang is like the boy who cried wolf. He's been promising an optical computer for years, and he's still promising. I'm waiting for him to prove that it's practical rather than it's possible." Others are skeptical that optics can compete with electronic computers. Says Bernard Soffer, senior scientist at Hughes Aircraft Research: "Optical computers would have to be ten to 100 times better than electronic ones to justify retooling." Even enthusiasts are guarded. Says optical-computing pioneer Joseph Goodman, a Stanford electrical- engineerin g professor who was once Huang's teacher: "The first commercial general-purpose optical computer will appear between the year 2000 and infinity, and it may be closer to infinity."
When it finally does appear, it may not be American. A group of 13 Japanese companies, including Mitsubishi and Nippon Electric, has teamed with the government's Ministry of International Trade and Industry to launch a ten-year optical-research program. Given the Japanese record in electronics, their interest in optical computers may be the best evidence that Huang and AT&T are on to something big.