RE: ...some kind of working context.
This gets closer. see bolded text...
Photonics West heralds the terabit-network era.
Electronic Engineering Times, Jan 31, 2000 p32
By Merritt, Rick
SAN JOSE, CALIF. - Researchers at Photonics West here last week spoke of new wave types and new materials that could lead to terabit networks and modulation at speeds hitting 100 GHz. The annual conference takes a wide-angle view of photonics across the spectrum of imaging, medical and industrial uses, but one clear force that ran through this year's event was the rise of the Internet, fueling innovation in optical components.
"For the past several years the growth of the Internet has been demanding fiber-optic networks-this is the driver," said J. J. Pan, a founder of E-Tek Dynamics Inc. (San Jose), an optical-components vendor scooped up in a $15 billion merger bid by JDS Uniphase Inc. (Nepean, Ontario) earlier this month. "Fiber-optic spending by 2002 is estimated to be at $25 billion, and I think that is conservative," Pan added.
Pan said he will plow some of the money he expects to reap from that deal into a new startup, Lightwaves 2020 Inc. (Santa Clara, Calif.). The company plans to develop thin-film coatings for optical bandpass filters that could be available within months. Further out it will work on optical switching componentry using liquid crystals and nonlinear materials. "The most important thing is that there will be no moving parts involved," he said.
Star turn
In another plenary address, Akira Hasegawa of Kochi University in Japan reported on the progress of the Soliton Total All-optical Research (Star) group he heads with support from Japan's Ministry of Posts and Telecommunications as well as seven companies, including NEC and Oki Electric. The group uses solitons, a nonlinear waveform that behaves like a particle, as the basis for advanced optical transmission systems.
To date Star has conducted successful experiments using solitons to achieve a 40-Gbit/second single-channel data transmission over 10,000 kilometers and a 1.1-Tbit/s transmission using 55 channels in a wavelength-division multiplexing (WDM) environment over 3,000 km. The group has also shown theoretically that solitons could transmit a 160-Gbit/s data stream on a single optical channel over 2,000 km. But proving that capability in an experiment could take the next three years, Hasegawa said.
The work demonstrates that terabit-class communications over distances as great as 10,000 km without forward error correction are feasible, Hasegawa said. What's more, the effort opens a door to ultrafast WDM systems, he added.
"Many people said solitons could not be used with WDM because their nonlinear pulse would create problems, but that's wrong," Hasegawa said. "We've demonstrated experimentally and theoretically [that] solitons are compatible with WDM."
Star started as a 10-year project to demonstrate terabit-class communications over 10,000 km using solitons, he said. "And we have largely accomplished this in just four years. Basically, now we are focusing on raising the speed per channel from 40 Gbits/s to 160 Gbits/s, without looking so much at the question of distance," said Hasegawa. "Distance is not a serious challenge since 70 percent of the undersea cables can be served by fiber lengths of 3,000 km or less."
However, one audience member noted that solitons have yet to prove themselves in the important area of spectral efficiency, where measurements of 0.8-bit/s/Hz are required. Hasegawa acknowledged the fact, noting that Star's experiments have to date not attempted to use filter controls.
In the area of materials, William Steier, professor of electrical engineering at the University of Southern California, presented work in new electro-optical polymers that he said could ultimately lead to Mach-Zehnder modulators for WDM systems running at frequencies as high as 100 GHz. Work at USC in EO polymers should result in the commercial release of 50-GHz modulators this year from a startup company called Pacific Wave with close ties to USC.
The work involved developing a new molecule, called a CLD chromophore, and marrying it to an amorphous polycarbonate host polymer from Lockheed Martin. A waveguide pattern is ion-etched into the resulting active polymer, which is then encased in a passive polymer sandwich to create a single modulator. As many as eight modulators have been put on a single silicon substrate. Experimental devices have run at frequencies as high as 113 Hz.
The new modulators would best today's fastest products from Lucent Tech-nologies, which use lithium-niobate materials to hit 30 GHz. "The question is once these EO polymers get out in people's hands, how stable will they be," said Steier. "We have held modulators at 60 degrees C for a few weeks, but that's not enough. We need to know if we can we run them at 100 mW and, if so, how they will hold up after a year." The new modulators could also find use in an RF photonics program Darpa is funding as part of a U.S. Navy project. However, Darpa has also taken keen interest in an alternative technology, electro-absorptive or quantum-well semiconductors, as the possible basis for high-speed modulators, Steier said. A number of small companies and university projects are now focusing on EA materials, he added.
Indeed, startups are flourishing all across the once-quiet sector of optoelectronics. "A lot of people think photonics will be the microelectronics of the next century," said Ray Chen, a professor at the University of Texas in Austin who chaired a session on optoelectronics. Chen has a startup, Radiant Research Inc. (Austin), that is putting its first WDM modules into beta testing and tying up a new round of financing in the process.
Not much available on Pacific Wave. |
