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With so much talk about the National Broadband Network (NBN) and fibre optic cabling, fibre optic may be a term that is familiar to you. But do you know what it means?

What is an optical fibre?

An optical fibre is made from high quality extruded glass or plastic. It is just a little thicker than a human hair and is flexible and transparent. One of the most important functions of an optical fibre is its capacity to transmit light from one end of a fibre to another.

How do optical fibres work?

Most often, optical fibres have a transparent core which is encased by transparent cladding material characterised by a lower index of refraction. Total internal reflection keeps light in the core and means that the fibre can function as a waveguide.

However, joining lengths of optical fibres is a more complicated process than that used to join electrical wire and cable. Care must be taken to cleave the ends of fibres, prior to mechanically splicing them together or using heat to fuse them.

Fibre optics and communication

As a result of its flexibility and the possibility of bundling it as cables, optical fibre is a suitable medium for computer networking and telecommunication. It carries particular advantages for communication over long distances and means that fewer repeaters are needed when optical fibre is spanned over long distances.

Because they facilitate transmission over significant distances and at greater bandwidths than is possible with other forms of communication, the use of optical fibres in fibre-optic communications is extensive.

There is a preference for fibres above metal wires because less loss of signal occurs as signals travel along fibres and they eliminate the problem of electromagnetic interference.

Fibre optic communication is all about the information transmission facilitated by pulses of light being sent through an optical fibre. The light becomes an electromagnetic carrier wave that, once modulated, is effective in carrying information.

The telecommunications industry has been profoundly influenced by fibre-optic communication systems, particularly the huge changes that have been brought about by the ‘Information Age’. Optical fibres have significant benefits that render this form of transmission preferable to electrical transmission and, as a result, have led to the widespread replacement of copper wire communications in core networks.

Available in a great range of sheathings and armour, modern fibre optic cables are appropriate for direct burial in trenches, high voltage isolation, insertion in paved streets and a range of other applications. Because the expense of small fibre-count cables mounted in poles has reduced significantly, more demand for fibre to the home (FTTH) installations has been observed in countries, including Japan and South Korea.

Steps associated with the use of fibre optics

There are four steps involved with communicating using fibre optics.

1. A transmitter is used to create the optical signal

2. The signal is relayed along the fibre, with care taken to ensure there is no distortion or weakness of the signal

3. The optical signal is received

4. The optical signal is converted so that it becomes an electrical signal.

Why is optical fibre so important to the NBN?

Fibre optics come with a range of appealing and important advantages over conventional copper wire systems.

Broad bandwith: Fibre optics help to facilitate speedy broadband communication and mean that the transmission of approximately 3 million voice or 90,000 television channels is possible via only one optical fibre.

No electromagnetic interference: The lightwaves which travel in optical fibres are not affected by any other nearby electromagnetic radiation. Importantly, optical fibre is electrically non-conductive.

Across long distances, low attenuation loss: The low attenuation of optical fibre cables means that efficient long distance communication is a reality.

Electrical insulator: The silica glass from which fibre optic cables are made renders them non-conductive to electricity. Essentially, this eliminates the potential problem of ground loops and leakage of current of any type.

Expensive metal conductor is not needed: Conventional cable systems demand significant amounts of copper, which serve as a conductor. Optical fibres do not need this.

Although the installation of fibre optic cables is expensive, it is predicted that almost all communications in the future will use fibre optics.