Glass has revolutionised modern communications in a way which its early makers could not have imagined. Fibre optics sends information coded in a beam of light down a glass or plastic pipe. It was originally developed for endoscopes in the 1950s to help doctors see inside the human body without having to cut it open first.
In 1967, Sir Charles Kuen Kao while a researcher at the Harlow research laboratories of Standard Telephone and Cable (STC) conceived the idea of using glass as a transmission medium for telecommunications. He reasoned that if one could shine light down a fine rod of glass then, because of internal reflection, most of the light would emerge from the other end. With the invention of semiconductor lasers and photodiodes (light transmitters and receivers), the light could be switched on and off at high speed and pulses of light could be the means of transmitting messages in binary code down the tube. Inherently the amount of digital information that could be transmitted would be much greater than using electricity and copper cables.
After collaborating with the US Corning glass company the idea was developed rapidly, new ultra-pure forms of glass were made creating fibres about the thickness of a human hair and evolving into today’s fibre optic cables. Sir Charles Kao was awarded the Nobel Prize for physics in 2009 for his contributions to the study of the transmission of light in optical fibres and for fibre communication.
In 1977 the first fibre-optic telephone cable was laid between Long Beach and Artesia, California. In 1997 a vast transatlantic fibre-optic telephone cable called FLAG (Fibre-optic Link Around the Globe) was laid between London, England and Tokyo, Japan.
This glass fibre has a multitude of uses from medicine – in non-invasive diagnostics and surgery, to technology, cable television, and telecommunications. The field of fibre optics communications has exploded over the past two decades. Fibre optic cables are an integral part of modern day communication infrastructure and can be found along roads, in buildings, hospitals and machinery. It is noticeable that although our installed domestic phone connections are all based on copper wire when TV cables were installed in recent times throughout our cities fibre optic cables only were used. However copper telephone cables are now being replaced with fibre optic cables which will increase the speed and capacity of our communication networks.
Made of specially formulated glass, drawn into threads just 125 microns thick, a single fibre in a transatlantic cable is capable of carrying up to 10 million simultaneous conversations. In addition, glass components are increasingly replacing electronic devices for applications such as switching.
Soon all communication will be carried over glass fibres. Optical fibres carry signals with much less energy loss than copper cable and with a much higher bandwidth. This means that fibres can carry more channels of information (voice, data, images) over longer distances and with fewer repeaters required. Optical fibre cables are also more secure. They are immune to electromagnetic interference and can be routed safely through explosive or flammable atmospheres e.g. in the petrochemical industry. In many ways, optical fibre systems work in the same way as electrical cables but they are cheaper, more reliable and much, much faster.