Charles K. Kao

Lore & Background

Sir Charles Kuen Kao was a Hong Kong electrical engineer recognized as the "father of fibre optics." He was a permanent resident of Hong Kong and a citizen of both the United Kingdom and the United States. In the 1960s, while working at Standard Telecommunication Laboratories in Harlow, England, Kao pioneered methods to combine glass fibres with lasers for transmitting digital data. He demonstrated that the high signal loss in existing fibres was caused by impurities in the glass, not by fundamental physical limitations, and identified fused silica as an ideal material for long-range optical communication. This work laid the groundwork for the Internet and the World Wide Web. Kao was awarded the Nobel Prize in Physics in 2009 for groundbreaking achievements concerning light transmission in fibres for optical communication, and was knighted by Queen Elizabeth II the following year. He held a Ph.D. in Electrical Engineering from University College London, obtained in 1965 with a thesis on waveguides. Kao also served at the Chinese University of Hong Kong and at ITT and Yale University in the United States. He was born in Shanghai in 1933 and settled in Hong Kong in 1949 after the Communist Revolution.

Reader's Guide

Charles K. Kao’s foundational work in fibre optics began in the 1960s at Standard Telecommunication Laboratories in Harlow, England. He was tasked with investigating why glass fibres lost light, and by collecting samples from various manufacturers and studying bulk glasses, he concluded that the high signal loss was caused by impurities in the glass, not by an inherent flaw in the technology itself. This insight overturned the prevailing skepticism about using glass for long-distance communication. Kao then developed methods to combine glass fibres with lasers for transmitting digital data, laying the groundwork for the Internet and the eventual creation of the World Wide Web. He is widely recognized as the "godfather of broadband" and the "father of fibre optics." His work earned him the 2009 Nobel Prize in Physics for groundbreaking achievements concerning light transmission in fibres for optical communication, and he was knighted the following year. Kao’s legacy endures in the fibre optic cables that now carry the vast majority of global telecommunications traffic, making him a central figure in the information age.

Did You Know?

• Charles K. Kao was awarded the Nobel Prize in Physics in 2009 for groundbreaking achievements concerning the transmission of light in fibres for optical communication.
• Kao demonstrated that the high loss in glass fibres arose from impurities in the glass, not from fundamental physical effects, and identified fused silica as an ideal candidate.
• Kao was a permanent resident of Hong Kong and a citizen of both the United Kingdom and the United States.