You can talk on the phone to someone who is far away. You can press a button and see a television show from another country. These sounds and pictures may be travelling to you in the form of light.
Fibre-optic cables make this possible. These cables are made from clear glass or plastic strands – sometimes as thin as a human hair. These strands or fibres are gathered into bundles and wrapped in a special covering. Light travels very fast through each one of these strands. And the light can carry messages faster and more clearly than old-fashioned copper wires.
Here is how a phone call in a fibre-optic system works. When you talk to a friend, the phone changes the sound of your voice into electric signals. Then a laser at one end of the fibre changes these electric signals into high-speed flashes of light. At the other end of the fibre, a special device changes the flashes back into electric signals. Your friend’s phone then changes these signals back into the sound of your voice.
Picture Credit : Google