Fibre

Fibre-Optics

This is a process that uses the transmission of light along a glass or Perspex fibre. Light entering one end of the fibre is repeatedly reflected on the outside of the inner part until it reaches the other end. Total internal reflection takes place as two types of glass are used and this involves very little energy lost at each reflection. Such fibres are very thinly made (less than 1 mm across) and are easily bent. Thus a cable consisting of many fibres can be laid in just the same way as normal copper ones. Up to 32 000 simultaneous telephone conversations can be carried for the same size of cable. Normal electrical signals (carrying data) are used to modulate a laser light beam that is sent to a receiver along an optical fibre.

Some advantages fibre optic cables have over traditional metal cable are that firstly they can carry more data; secondly, they are less affected by interference; thirdly they are much thinner and lighter and finally data can be transmitted digitally (i.e. natural form of computer data which is in binary digit) instead of analogically. Its main disadvantage being its cost, they are very expensive and much more fragile than wires, this renders the splitting of the cable very difficult. Fibre optics is particularly popular for LANs (Local Area Networks). Telephone companies are also gradually replacing the old telephone lines with these cables and in a near future almost all communications will employ fibre optics.

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