Charles K. Kao was an electrical engineer who, working at Standard Telecommunication Laboratories with George Hockham in 1965-66, showed that the high signal loss in existing optical fibres came from impurities in the glass rather than any fundamental limit of the technology, and that sufficiently pure glass fibre could carry light signals over long distances. That loss-proposal became the theoretical foundation of practical fibre-optic communication. Kao later served as Vice-Chancellor of the Chinese University of Hong Kong (1970-1996) and was awarded the 2009 Nobel Prize in Physics for his achievement. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/
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NationalityBritish and American citizen, permanent resident of Hong Kong 1 Learn More
Kao, Hockham, and the Proposal Nobody Believed
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In 1965, the glass fiber then available for guiding light lost most of its signal within a few meters, far too lossy for any real communications use. Charles Kao and George Hockham, working at Standard Telephones and Cables, argued that the loss was not a property of glass itself but of the impurities inside it, and that a fiber purified below twenty decibels of loss per kilometer would be practical for telecommunications. The claim was bold enough that much of the field doubted it. Kao spent years afterward pressing glassmakers to test the idea rather than dismiss it, and in 2009 the wait was rewarded: he shared the Nobel Prize in Physics for a proposal that had taken the telecommunications industry most of two decades to fully believe and adopt. The proof that Kao and Hockham were right did not come from them. It came from a glass company that had never made a telephone cable in its life.
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Pioneered the use of optical fiber for long-distance telecommunications.
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Showed in 1965-66, with George Hockham, that sufficiently pure glass fibre could transmit light signals over long distances, the theoretical foundation of practical fibre-optic communication; awarded the 2009 Nobel Prize in Physics for the achievement.
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1. Charles K. Kao (Wikipedia)
Wikipedia contributors, Wikimedia FoundationAcademic Career section
The high-loss of existing fibre optics arose from impurities in the glass, rather than from an underlying problem with the technology itself.
- Invented: The Optical Fiber
View the Source Frequently Asked Questions
What did Charles Kao show that made optical fibre practical for communication?
He showed that impurities, not the technology itself, caused fibre loss, and set a 20 dB/km target that opened the race for low-loss glass.
At Standard Telecommunication Laboratories in Harlow, Kao and his coworkers showed that the high loss of existing fibres came from impurities in the glass rather than from an underlying problem with the technology. In 1965 he and George Hockham concluded that the fundamental limit on glass light attenuation is below 20 dB/km, while fibres of the time commonly lost 1,000 dB/km or more. Their results were presented to the IEE in January 1966 and published that July. Kao pointed to high-purity fused silica as an ideal candidate, and in 2009 he was awarded the Nobel Prize in Physics for groundbreaking achievements concerning the transmission of light in fibres for optical communication.
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