Forty years after he worked out how to make glass fibres transmit data in the form of light and changed the face of telecommunications, Professor Charles Kao CBE FREng FRS has won this year’s Nobel Prize in Physics, jointly with Willard Boyle and George Smith, formerly of Bell Laboratories, for the invention of digital imaging technology.
In 1966 Charles Kao and his co-worker, George Hockham FREng, published research that today means the internet can transport vast amount of data virtually for free. Their work on transmitting light through glass filaments the thickness of a human hair opened the way to worldwide direct dialling, cable TV and the internet, yet surprisingly their initial objective was a modest 140mbit/sec data rate because that was what the market needed at the time.
“Kao did two things,” says Professor John Midwinter OBE FREng FRS, who pioneered BT’s adoption of optical fibre technology. “He laid down the gauntlet in proposing the use of optical fibres for communication in 1966 and he calculated the necessary properties (better than 20dB/km attenuation). He crystallised the idea of making a glass fibre wave guide, but nobody had any idea how to make one!
“Kao also made extremely careful measurements on bulk glass samples showing that glasses existed with low enough losses to make the technology work. Corning reported a silica fibre with low enough losses at a meeting in London in 1970, but it was very fragile so an intense period of work ensued to make flexible fibres.”
The breakthroughs in flexibility came in 1975 and the first trial links were laid in 1977. Professor Midwinter and his team laid a 13 km cable from Martlesham to Ipswich. STL Harlow linked Hitchin and Stevenage, but they used two regenerators (signal amplifiers). The original regenerators were electrical – the whole transfer process is now optical with optical regenerators about every 40 km. A single optical fibre can carry up to 32 times the data possible through a copper wire – fibre is also much cheaper than copper wire and many times thinner. The first transatlantic cable link, 6,000 km long, was not laid until 1988.
Professor Kao now lives in Hong Kong and the US, but his seminal work was carried out at Standard Telecommunication Laboratories, Harlow, shortly after he completed his PhD at the University of London. His studied for his first degree at Woolwich Polytechnic, now Greenwich University. Latterly he became Vice Chancellor of the Chinese University of Hong Kong and an adviser to the Hong Kong government on telecommunications policy. He was elected to the Academy in 1989 and was awarded the Prince Philip Medal in 1996.
“Charles’ work in establishing the world changing field of optical fibre communications is characterised by an unusual combination of attributes,” says Professor Midwinter. “Excellent theoretical and experimental science coupled with a solid grasp of what the telecommunications market actually needed in the 1970s. The result was that his work focused attention on solving all the key problems to enable the launch of a successful product whilst not detracting from the excellence and fascination of the science. This was never science for the glory of God, even though it was glorious but always skilfully aimed fundamental research.”
Notes for editors
For the full Nobel Prize citation see nobelprize.org/nobel_prizes/physics/laureates/2009/press.html
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