This is a very important application of total internal reflection.
Electromagnetic radiation, this can be light or infra red radiation depending on the
application, is shone along a thin glass fibre and as it hits the glass-air boundary at more
than the critical angle it reflects along inside the fibre.
Uses of Fibre Optics
In many of
the following uses each fibre has an outer cladding of glass and a bundle of the fibres can be
enclosed by a plastic cover.
1. Communications – sending information along a light
beam. This is useful for telephone, television, radio, computer networks, stereo links, control
in aircraft .
2. Endoscopy - seeing down inside a patient's body
3. Illuminating models
or road signs using only one bulb
4. Security fencing – very difficult to
Advantages of fibre optics over copper wire
1. Cheap – glass
is made from silica, the basic constituent of sand
2. Light in weight – and so it is useful in
3. The light beam can carry a huge amount of information because its frequency
is so high
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