Fiber optics goes nano

Researchers working to make microscopic and nanoscale machines and electronics have produced electrical wires at that scale, but it has proved more difficult to shrink the fiber optics that guide light. The trick to guiding light is finding ways to keep the photons confined to a fiber rather than leaking out.

Researchers from Harvard University, Zhejiang University in China and Tohoku University in Japan have made glass optical fibers as thin as 50 nanometers that guide light without losing much of it. Fifty nanometers is more than one thousand times finer than human hair. The researchers have made the thin optical fibers up to several centimeters long.

The key to such small, low-loss optical fibers was finding a way to make them very uniform in diameter and with very smooth walls, according to the researchers. To make the fibers the researchers first used a flame-drawing method to make micron-sized fiber. They then wound the fiber around a tapered, heated, 80-micron-diameter sapphire tip to keep the wire at a steady temperature while they pulled the fiber a second time to make it thinner.

The tiny optical fibers could be used in microphotonic devices for optical communications and optical sensing. The smaller fibers could lead to smaller and/or faster devices, according to the researchers.

The tiny fibers could be used in practical applications in two to five years, according to the researchers. The work appeared in the December 18/25, 2003 issue of Nature.