Page 57 - Curriculum Visions Dynamic Book

Thinnest glass microfibre (1 micron – 1 millionth of a metre)
Typical optical fibre (10 microns) for mono mode
Typical fibreglass textile fibre (14 microns) Human hair
Glass optical communications fibre to carry multiple beams (50–125 microns or larger) for multimode use
The glass is coated with a plastic to protect it from being scratched or scuffed when handled.
Optical fibres have many advantages over traditional copper wires. They are lighter, they can carry more information,
they take up less space, and the signals travel faster. The glass melts at a higher temperature and so is resistant to melting in fires. Signals also fade more slowly in glass than in copper, and so there can be longer distances before the signals need to be amplified.
For fibres to be effective, the glass must be very pure; it must be free of bubbles or any surface defects.
Optical signals are sent by laser. Optical fibres can transmit tens of thousands of telephone calls or computer communications at the same time.
(90 microns)
(Left) Glass fibre diameters compared.
(Left and right)
Optical fibres transmit light along their lengths. Optical fibres are being installed across the country to allow improvements in modern communications.
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