So many people are tapping into the Internet that conventional fiber optic cable may not meet the demand. But a University of Utah expert says electrical or optical "pumps" could boost the cables' signals, vastly improving transmission.
"The infrared range (of light transmission) soon will be saturated, so other wavelengths will have to be considered," wrote Z. Valy Vardeny, chairman of the U. physics department, in the current issue the scientific journal Nature.
Light signals will need to be amplified in the cables.
Vardeny, distinguished professor and the head of a research team, offered suggestions for further research. "For the moment, these amplification schemes remain pie in the sky," he wrote.
Nevertheless, new ideas are promising, "and one way or the other we will have to find ways to expand the capacities of fiber-optics systems."
The development of fiber optics in the past few decades was a revolution in telecommunications. By bouncing infrared light beams along a spun-glass cable, the amount of data transmitted was increased tremendously over the rates available with wire cable.
In the late 1990s, Vardeny and others described methods to improve the ability of fiber optics to carry information. "We were the first to show laser action of polymer rings surrounding fiber optics" cables, he noted in an interview last week.
In January, S.X. Dou and colleagues from the Laboratorie de Photonique Quantique et Moleculaire in Cachan, France, reported on possible applications of that idea. Their research focused on a device that could amplify visual light if used in certain kinds of new fiber cables.
In "A Boost for Fibre Optics," printed in the April 4 edition of Nature, published in Great Britain, Vardeny discusses Dou's findings and offers suggestions for additional research.
Vardeny wrote that a way to improve transmission would be by reducing attenuation of the signal within the cable.
"In any material there is absorption," Vardeny told the Deseret News. "The absorption in glass, for example, in the range of 1.3 to 1.5 microns (the frequency of light used in fiber optics) is very low, but it's still there."
Because the cables can be extremely long, light absorption eventually can add up. "After a while, the information-bearing beam will be attenuated," he said.
"So you need to boost its intensity."
Vardeny discusses ways to boost the light beam through manipulating a special polymer on the outside of the cable. The amplification, or pumping, can be through optical or electrical stimulation.
The problem with optical stimulation is that a light beam used to do that also faces the same sort of attenuation that reduces the performance of the message beam. For extremely long lines, such as optical cables crossing oceans, this becomes a serious drawback.
"Therefore, our next stage is to do it electrically," he said.
A new material called organic light-emitting diodes might fill the bill.
Three layers would be wrapped around the cable: a positive electrode material, then the polymer, then a negative electrode. These would form a tiny cylinder. Electricity is added and light is emitted, in effect recharging the cable's beam.
"This will be like a small battery," Vardeny noted. The information beam dancing through the cable "will be boosted by the light emitted by the polymer." Randy Polson, a Ph.D. student working with Vardeny, said a promising material that U. scientists intend to study with optical cables is called a pi-conjugated polymer. The material helps to create a laser-type effect, he said.
Future experiments will try to boost optical signals using some of these processes.
"That's one of the reasons I got into physics," Polson added. "I try to do new and exciting things."
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