Charles Kuen Kao

Abstract

At STL, Charlie became part of a team that was exploring alternatives to existing telecommunications that used coaxial cables or radio signals and operated at megahertz frequencies. The researchers looked at hollow metal waveguides that could operate at gigahertz frequencies but ultimately rejected them. They then considered several optical waveguide designs in which the light would be mostly guided in air and thus avoid material losses. By 1965 Charlie was leading the STL team. He changed its focus to optical fibers, and in 1966 he and George Hockham, with Gwen’s assistance, wrote a seminal paper in which they concluded that eliminating glass impurities would reduce losses below 20 dB/km, the threshold for commercial viability. Charlie realized that a worldwide effort was needed to turn that theoretical possibility into a reality, so he crisscrossed the globe and mobilized numerous participants in that ultimately successful effort.