Bulletin Special Supplement on Prof. Charles K. Kao, Former Vice-Chancellor and Nobel Laureate The Love and Labour of a Laureate

26  Chinese University Bulletin Special Supplement 2010  spec trophotometer yielded a sensitivity down to 4.3 dB/km. T h e r e f l e c t i o n e f f e c t w a s measured with a homemade ellipsometer. To make it, they used fused quartz samples made by plasma deposition, in which the high temperature evaporated the impurity ions. With the sensitive instrument, the attenuation of a number of glass samples was measured and, eureka, the Infrasil sample from Schott Glass showed an attenuation as low as 5 dB/km at a window around 0.85 micron — at last proving that the removal of impurity would lower the absorption loss to useful levels. This was really exciting because the low-loss region is right at the gallium-arsenide laser emission band. The measurements clearly po i n t e d t h e wa y t o op t i c a l commun i c a t i on — compa c t gallium-arsenide semiconductor lasers as the source, low-cost c l add e d g l a s s f i b e r s a s t he transmission medium, and silicon or germanium semiconductors for detection. The dream no longer seemed remote. These measurements apparently turned the sentiments of the research community around. The race to develop the first low-loss glass fiber waveguide was on. In 1967, at Corning, Maurer’s chemist colleague Schultz helped to purify the glass. In 1968, his colleagues Keck and Zimar helped to draw the fibers. By 1970, Corning had produced a fiber waveguide with a loss of 17 dB/km at 0.633 micron using a titanium-diffused core with silica cladding, using the Outside Vapor Deposition (OVD) method. Two years later, they reduced the loss to 4 dB/km for a multimode fiber by replacing the titanium-doped core with a germanium-doped core. Bell Labs finally got on the bandwagon in 1969 and created a program in optical fiber research after having been skeptical for years. Their work on hollow light pipes was