Charles Kao helped make long-distance optical-fiber communication practical.
In the 1960s, Kao argued that glass fibers could carry information over long distances if their signal losses were reduced sufficiently. At the time, existing fibers were too impure and absorbed or scattered too much light. Kao’s analysis identified manufacturing improvements that could make fiber-optic communication viable.
Kao shared half of the 2009 Nobel Prize in Physics for this achievement. The other half went to Willard Boyle and George E. Smith for the invention of the charge-coupled device, or CCD. Optical fibers transmit pulses of light through thin glass or plastic strands and now carry internet, telephone, and television signals. Kao did not invent every component of fiber-optic systems; his key contribution was recognizing and defining the conditions needed for practical low-loss transmission.