Optical fibres can carry information coded in light or infrared signals. Optical fibres can carry more information than an ordinary cable of the same diameter.
Analogue signals vary continuously in amplitude [amplitude: The maximum height of a wave, measured from the mid-point of its vibration. ], frequencyfrequency: The number of repetitions per second of a wave. The unit of frequency is the hertz, 'Hz'. or both. Digital signals are a series of pulses with two states – on or off. Digital signals carry more information per second than analogue signals, and they maintain their quality better over long distances.

Optical fibres
An optical fibre is a thin rod of high-quality glass. Very little light is absorbed by the glass. Light getting in at one end undergoes repeated total internal reflection, even when the fibre is bent, and emerges at the other end.
Information such as computer data and telephone calls can be converted into electrical signals. These can be carried through cables, or transmitted as microwaves or radio waves. However, the information can also be converted into either visible light signals or infrared signals, and transmitted by optical fibres.
Optical fibres can carry more information than an ordinary cable of the same thickness. The signals in optical fibres do not weaken as much over long distances as the signals in ordinary cables.

Optical fibre
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