A World Connected by Light: The Nobel Prize Winning Work of Charles Kao (1933-2018)

When the Nobel Prize in Physics is announced each year, a large part of the world receives the message almost instantly – in words, images, speech and video – shuffled around in optical fibers at nearly the speed of light. It is something that many of us take for granted, forgetting the source of where of this innovation comes from

The scientist who made the discovery was Charles Kao (4 Nov 1933 – 23 Sep 2018). Working in England in the 1960s, Kao presented fibers of very pure glass that could transport light without losing too much light along the way. Together with laser technology, Kao’s discovery revolutionized modern telecommunications in a way only visionaries like him can foresee.

The idea that thin filaments or fibers of glass could be useful to science came before Kao. In the 1930s, such fibers were used to see inside the body, but for a long time, they remained unusable for long-distance information transfer because too much light was lost along the way.

In January 1966, at the age of just 33, Kao found a solution to reduce the loss of light after calculating how to transmit light over long distances via optical glass fibers. With a fiber of purest glass, it would be possible to transmit light signals over 100 km compared to only 20m for the fibers available in the 1960s. Today, optical fibers make up the “circulatory system” of the global communications system, facilitating fast and virtually noise-free transfer of information without which broadband communications like the internet would not be possible.

Charles Kao doing an early experiment on optical fiber at the Standard Telecommunications Laboratory in Harlow, England, in the 1960s. Credit: The Chinese University of Hong Kong via EPA.

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