Fiber To Dye For

Byline: Rob Terry

A little-known chemical reaction key to making tie-dye T-shirts may spur advances in fiber-optic communications.

Four researchers at Virginia Tech in Blacksburg are developing materials to make polymer films that may enable better control of laser light used in super-fast telecommunications networks.

The key ingredient is Procion Red, a dye commonly used to create the colorful, swirling shirt patterns.

The Virginia Tech team - physicist Randy Heflin, biochemical engineer Kevin Van Cott, chemical engineer Richey Davis and chemist Harry Gibson - takes its cues from the age of nanostructure assembly, not the Age of Aquarius.

But if the dye can be used to make better components for electro-optic modulators - devices that convert electrical signals to optical ones - then faster and cheaper signal conversion might be possible.

"There seems to be a bit of excitement about it," says Van Cott. "There is still a lot of work that needs to be done."

In fiber optics, data is converted to light and carried at high speeds over glass fibers. Fiber-optic gear turns lasers and other light sources on and off to direct information through a network. With a microscopically thin film able to better modulate the way light refracts, light can be made to travel faster and at lower cost to network operators.

Think of the film as a door controlling light entering a room. As applied to optical communications, researchers think a faster way to control the light would be to leave the light on and open and close the door, rather than start and stop the power source.

"It's not so much a power source as it is a speed one," says Heflin. "With these [electro-optic modulators], you can actually turn the light on and off more quickly ... as opposed to actually turning the power to the laser on and off."

The Virginia Tech team thinks modulators made with these new materials could be up to 10 times faster than existing gear.

"If EO modulators could be made cheaply enough to be used in the home or office, that could greatly speed up access to the Internet," said chemical engineering professor Davis.

Procion Red, the T-shirt dye, comes into play because its chemical properties give the film greater durability to withstand electricity shot through the film.

It's the same property that reacts to the cotton in T-shirts.

Biochemical engineer Van Cott came across the idea of using the dye for the films while reading a book on pharmaceutical purification.

"Serendipitously we were able to stumble across it and figure out the right conditions," he said.

The team presented its findings during April's American Chemical Society national meeting and will have a paper published in a German chemistry journal. They also hope to supplement their initial $250,000 in research funding with a $2 million grant from the National Science Foundation, in hopes of having a product ready in a year.

"[The research project so far] has been very successful," said Heflin. "And the NSF has made a major push in the area of nanotechnology ... and combining it with other disciplines."

Far out.

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