What is Optical Fibre? Why is it better than Copper Wire for using the Internet?

An optical fibre is a solid rod of transparent material, which can be as fine as a strand of human hair, designed to efficiently guide light from one place to another.

The most common raw material for making optical fibres is very pure silica sand. This is used because it is relatively inexpensive and can be formed into an ultra pure glass.

When you use a computer to do something like sending an email or making a ‘phone call, your text or voice (the data) needs to be transmitted from computer to computer.  A possible way of doing this is sending it via a cable, and the choice is between electrical transmission over copper wire and optical transmission over fibre.

Optical transmission has several advantages over copper wire:

• optical fibre’s high bandwidth means that a lot more data can be transmitted faster.
  A pair of copper wires (which is what most houses in urban areas use for the initial point of access to the Internet – see What is Fibre to the Node? for more info) can transmit two telephone calls simultaneously, while a single optical fibre can transmit over 80,000;
• glass is cheaper and lighter than copper;
• optical fibre is unaffected by electro-magnetic interference, and so is ideal in electrically “noisy” environments, eg where there is high voltage equipment nearby;
• no electrical current is transmitted down a fibre (glass is a good insulator), so it is suitable in hazardous environments where electrical discharge would dangerous;
• as transmission technology continues to improve, higher and higher bandwidths are possible over the same optical fibre links without having to replace the cables.