What is an optical fiber? Simply put, it's a glass fiber which can transmit light waves.
The first communication systems of mankind were a major effort, but their capacities were limited. Pigeons used to send letters are one such example. With the discovery of electrical waves the electronic media has increased continuously. Now, the telephone, the telegraph, radios, and television make it possible to rapidly transmit information in large quantities. This has made it possible for today's information network to reach everywhere.
The capacity of information which a communication line, like a telephone line for example, can hold is related to the frequency. Usually, the higher the frequency, the greater the amount of information which can be transmitted. Is there any other means of transmitting information which is greater in capacity and faster than electrical waves?
Scientists have found that the frequency of light is 1000 times that of the shortest radio wave frequency. This means that if light waves can be used to transmit information then its speed and capacity will be 1000 times that of electrical waves. So people have always dreamt of using light as a means of communication.
Actually, the use of light waves to transmit information dates back to a very early period. When we were children we used to play a game in which a mirror was used to reflect the sun's rays upon the wall. The ray of light perhaps conveyed a secret message understood by the people playing the game, a type of optic communication. Other examples include beacon fires and lighthouses; these too are means of optic communication. These methods of communication, however, are limited by environmental conditions and weather.
It wasn't until 1960 when an American scientist used a xenon light to irradiate a ruby, causing the atoms of the ruby to be stirred up and emitted a continuous red light known as a laser ray. The frequency of its light waves was orderly, and could be projected in a straight line until it was collected by a lens. It finally paved the way for a bright future for optic communication. It's a pity though that light waves still lacked a suitable transmission medium.
In 1970, Corning, an American glass company, was the first to use highly purified quartz to make an optical fiber which only lost twenty decibels of transmission per kilometer.
In 1976, AT & T (a U.S. company) installed an optical fiber cable between Atlanta and Chicago; the first long-distance on-the-spot testing of such a system. This optical cable replaced the former copper cable traditionally used as a means of communication.
The technology involved in making optical fiber cables is rather developed and can be employed commercially on a mass production basis, but scientists are still hard at work day and night working to create a highly advanced technology for the future.
Seen here is a thin optical fiber. After layers of jackets are added it will become an optical fiber cable.
The first step in manufacturing optical fiber: burning a perform fabrication.
Optical cables can rapidly transmit information on a large-scale basis. （photo by Vincent Cheng）
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