“The masters of light” is how the Royal Swedish Academy of Sciences described Charles Kuen Kao, Willard Sterling Boyle, and George Elwood Smith to whom it awarded this year’s Nobel Prize in Physics. Dr. Kao wins half the prize for his role in the development of optical fibres that have revolutionised communications across the world. Drs. Boyle and Smith share the other half for their invention of an imaging sensor known as the CCD (or charge-coupled device). Working at the Standard Telecommunication Laboratories in the U.K. in the 1960s, Shanghai-born Dr. Kao began studying how light could be harnessed for long-distance communications. It was known that glass fibres could carry light. But the problem was that 99 per cent of the light put in at one end of a fibre was dissipated by the time it travelled just 20 metres. Dr. Kao and his small team set themselves the goal of extending that distance to at least one kilometre. The bottleneck was not imperfections in the fibre, as was thought to be the case, but impurities in the glass. Dr. Kao and his co-workers showed that glass fibres made from fused silica had the purity needed for optical communications. These days, more than 95 per cent of the light is left even after being carried one kilometre in a modern optical fibre. Meanwhile, across the Atlantic at the famed Bell Labs in the U.S., Drs. Boyle and Smith were trying to come up with a better electronic memory. The device they produced — the CCD — became instead a way of electronically capturing images.
Optical fibres, carrying once unimaginable amounts of information, have made the world a far smaller place. Cables that contain thousands of glass fibres, each thinner than a hair, straddle the globe. The worldwide fibre optical network already has a total length of over one billion kilometres, sufficient to encircle the globe 25,000 times — and is growing every hour. These fibres link continents, countries, and communities, carrying valuable data and telephone conversations. The optical fibre is the backbone of the Internet, taking web pages, emails, chats, Skype calls, YouTube videos, and much else instantly across the globe. The video and images that are being transmitted in this fashion are likely to come from cameras equipped with a CCD or a similar device. Photographic film has vanished; instead there are mobile phone cameras that work using a CCD. The magnificent pictures taken by the space-orbiting telescopes like the Hubble and powerful ground-based ones too rely on such sensors. So do cameras on spacecraft that orbit Earth and go out into space. In his will, Alfred Nobel declared that the prizes in his name should go to those who “shall have conferred the greatest benefit on mankind.” This year’s Nobel Prize in Physics certainly meets that criterion.
