MURRAY HILL, N.J., Nov. 15 (UPI) -- When it comes to increasing the speed limit on the information superhighway's main lines, chains of organic molecules called polymers will take the place of semiconductor chips that currently send data on its way, researchers said Friday.
An experiment published in the current issue of the journal Science, performed by scientists at Bell Laboratories' Lucent Technologies in Murray Hill, demonstrates the polymer's potential role as an optical modulator, which encodes data onto a laser beam for transport across fiber-optic cables.
Led by staff member Mark Lee, the Bell Labs team optimized the polymer to reduce the amount of energy lost during transmission, while maintaining the molecules' ability to refract light at the same pace as the electric input signal.
"We achieved a practical, useful bandwidth of between 150 gigahertz and 200 gigahertz," Lee told United Press International. "Even in the worst-case scenario, we were at about 110 gigahertz, which is about three times better than (cutting-edge semiconductor modulators)."
Commercial modulators run today at about 10 gigahertz, or billion oscillations per second, enough to transmit all the data stored in a common personal computer in about 20 seconds.
Earlier polymer research had demonstrated the materials could operate at the 110 gigahertz frequency only, and ran into problems with instabilities caused by heat and the intensity of the laser itself, said Thomas Mino, chief operating officer of Lumera, of Bothell, Wash., a maker of optical communications components.
"(Lucent's) device actually modulates the light (to transmit data) ... and has detectable signals in the (trillions of hertz) kind of range," Mino told UPI. "They're verifying the work that's gone on, and that polymers have the kind of performance capabilities that people have projected for them."
Lee stressed the terahertz signals, which would translate to data transmission speeds 100 times faster than today's networks, are only at the most basic laboratory stage. Much more work is needed, including improving the performance of the modulator's electrical contacts, to reduce power losses to the point where such signals could be effectively modulated, he said.
Another benefit of the polymer modulator is its low power requirement, Mino said. Today's systems rely on a semiconductor material called lithium niobate, and require a 10-volt current to operate. An equivalent polymer component, one of the devices Lumera is readying for the market, provides a slightly stronger signal at only 2.5 volts, low enough to work with existing computer chips without the power-boosting components needed today.
This low-power, simplified arrangement could lead to reducing the number of signal repeaters a network requires to send data through thousands of miles of cable, Mino said.
Lucent's polymer modulators are not quite ready for prime-time, however, Lee told UPI. Component suppliers such as Lumera are concerned about the material's stability over months and even years, he said, and engineers must devise packaging methods to preserve the polymer.
Another challenge involves the fact that light spreads out as it travels, especially if a wide range of frequencies are used, Lee said. Data from the polymer modulator could be lost over extended distances unless engineers are sure anti-dispersion coatings on the optic fiber will handle the device's output, he said.
Developers have plenty of time to solve these issues, Mino said, since data and telephone providers are still at the 10 gigahertz level. Even the 40 gigahertz devices using existing technology will be integrated slowly.
