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

The Nobel Lecture  25 5. Convincing the world The substance of the paper was presented by Dr. Kao at an IEE meeting in February 1966. Most of the world did not take notice — except for the British Post Office (BPO) and the UK Ministry of Defense, who immediately launched major research programs. By the end of 1966, three groups in the UK were studying the various issues involved: Kao himself at STL; Roberts at BPO; Gambling at Southampton in collaboration with Williams at the Ministry of Defense Laboratory. In the next few years, Dr. Kao travelled the globe to push his idea: to Japan, where enduring friendships were made dating from those early days; to research labs in Germany, in the Netherlands and elsewhere to spread his news. He said that until more and more jumped on the bandwagon, the use of glass fibers would not take off. He had tremendous conviction in the face of widespread skepticism. The global telephony industry is huge, too large to be changed by a single person or even a single country, but he was persistent and his enthusiasm was contagious, and slowly he converted others to be believers. The experts at first proclaimed that the materials were the most severe of the intrinsic insurmountable problems. Gambling wrote that British Telecom had been ‘somewhat scathing’ about the proposal earlier, and Bell Labs, who could easily have led the field, simply failed to take notice until the proven technology was pointed out to them. Dr. Kao visited many glass manufacturers to persuade them to produce the clear glass required. He got a response from Corning, where Maurer led the first group that later produced the glass rods and developed the techniques to make the glass fibers to the required specifications. Meanwhile, Dr. Kao continued to pour energy into proving the feasibility of glass fibers as the medium for long-haul optical transmission. They faced a number of formidable challenges. The first was the measurement techniques for low-loss samples that were obtainable only in lengths of around 20 cm. The problem of assuring surface perfection was also formidable. Another problem is end surface reflection loss, caused by the polishing process. They faced a measurement impasse that demanded the detection of a loss difference between two samples of less than 0.1%, when the total loss of the entire 20 cm sample is only 0.1%. An inexact measurement would be meaningless. In 1968 and 1969, Dr. Kao and his colleagues Davies, Jones and Wright at STL published a series of papers on the attenuation measurements of glass that addressed the above problems. At that time, the measuring instruments called spectrophotometres had a rather limited sensitivity — in the range of 43 dB/km. The measurement was very difficult: even a minute contamination could have caused a loss comparable to the attenuation itself, while surface effects could easily be 10 times worse. Dr. Kao and the team assembled a homemade single-beam spectrophotometre that achieved a sensitivity of 21.7 dB/km. Later improvements with a double-beam