Fiber optics works by transmitting light rays in a glass strand. The physics of fiber optics are simple to explain and understand. Light signals can travel very long distances, and still be recognizable. When you look up at a starry night sky, you are seeing the lights generated from stars that are billions of miles from you. Yet your eyes, without aid of magnification or amplification, can see the individual stars in the sky. Even though the light rays may have been travelling for years before they reach you, they are still viewable. Because of resistance and interference, electrical signals can become indistinguishable in relatively short distances, where fiber can carry telephone signals from continent to continent, covering thousands of miles and retaining complete signal integrity.
In the 1960s it was found that silica glass, made from common sand, could be melted and formed into a solid thin strand or fiber that could be used to carry optical signals with an acceptable amount of loss over distance. After a lengthy developmental period, optical fiber systems were initially installed for testing by the telephone companies in the early 1980s, with the first commercial system linking New York City and Boston, carrying long-distance telephone calls.