A man of fibre

A man of fibreThe father of fibre optic communications Professor Charles Kuen Kao has looked into the future and seen new technology and social change. Adrain Morant shared the experience with him
Whether we know it or not, we are all beneficiaries of the work carried out by Professor Charles Kuen Kao.
The 1966 Kao and George Hockham worked at the Standard Telecommunications (now Nortel) Laboratories in Harlow. Here they wrote their seminal paper which is the foundation of fibre optic communication. Without this, the whole of today’s high-tech world (as well as much of the rest of it) would grind to a halt. He has often been referred to as the father of fibre optic communications.
Kao was predicting 100Mbit/s to the desktop well over ten years ago. He could not give any real idea what it would be used for but, as he said then: “Whenever we have given people extra bandwidth they have always found a use for it.”
In London recently, he gave the Institution of Electrical Engineers Annual International Lecture entitled Engineering the Future. In his lecture he painted with a broader brush.
He looked way ahead and focused on a number of issues rather than on the tactical development of today.
He pointed out that the performance of ICs, which has been improving by a factor of two every two years, can be expected to continue for the next 12 years or more using the basic design and principles of operation of the current devices. In the longer term, the direction taken to improve the overall operational capabilities will be by using tailored semiconductor materials and through working towards atomic-size devices. “Both these directions will need a major shift in material and device operating principles.”
He noted that, while optical fibre communications is the basic infrastructure of the wired networks, wireless communications is needed for “anywhere” access. The wired network capacity can be expanded indefinitely by installing more fibres. This makes network bandwidth virtually unlimited, in contrast, free space bandwidth is limited and not interference free.
Overall, despite the increase in the capacity of optical systems – both transmission and switching – there are many challenges that still lay ahead in designing practical networks for the future. For instance, services could generate unpredictable and chaotic traffic.
Optimum investment strategy for building future networks is an open issue.
Operators have the conflicting requirements of guaranteeing service quality while keeping tariffs low enough to attract custom.
Kao pointed out that traditionally we have met our hardware needs using naturally available materials even though they have needed extensive purification and refinement. Now techniques have been developed to produce synthetic materials of the quality and characteristics needed to meet specific application requirements.
More has to be done in this direction. Here he cited the need for semiconductors with tailored electronic band-gaps for laser applications at particular frequencies.
This is an area where he has vast experience. Kao was the first executive scientist and subsequently the corporate director of research at ITT. In the early 1980s he launched a programme addressing the high frequency limits of signal processing known as ‘terabit technology’ to assist managers to improve the effectiveness of materials and device research.
Among the other areas he touched on was biotechnology and commented that it may become important to electronics and optics because certain properties in the biological field , such as memory, self-regeneration and control, are the functions that machines need to emulate. “Bio-molecules may provide some clues as to how living cells achieve such functions, or how they can be used as bio-electronic materials.”
He explained that improved understanding of science often helps to advance the state-of-the-art of technology. Sometimes, pushing the limits in one direction, can even lead to new scientific discoveries.


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