 It is especially advantageous for long-distance communications, because light propagates through the fiber with little attenuation compared to electrical cables.This allows long distances to be spanned with few repeaters.In 1966 Charles K. Kao and George Hockham proposed optical fibers at STC Laboratories (STL) at Harlow, England, when they showed that the losses of 1000 dB/km in existing glass (compared to 5-10 dB/km in coaxial cable) was due to contaminants, which could potentially be removed.