Fiber-optic technology is the foundation of telecommunications that allows us to exchange information as light travels along glass or plastic strands or fibers. It's incredibly durable and transmits data over long distances. Its impressive performance has transformed modern methods of data exchange and how we communicate, from the Internet to telephone calls. Its durability also makes it less susceptible to power outages and electromagnetic interference than copper connections.
One of the most astounding engineering feats was the first ocean spanning fiber-optic cable called TAT-8, which extended from Tuckerton, New Jersey to Widemouth and Penmarch in England. This cable was less than a tenth of an inch in diameter, yet it could carry about 40,000 simultaneous phone calls. Engineers carefully designed the cable to survive the pressures of the deep ocean, wrapping optical fibers around central steel wires and sealing them inside a copper cylinder for protection from water.
The signal in a fiber-optic cable is converted from electrical to optical by an electric device called a transmitter. Its drive circuit varies the current flow to the light source, which changes the irradiance and sends this varying signal down the fiber. The receiver then detects the light signals and converts them to electronic data for transmission.
To maximize the amount of data that can be transmitted over a fiber-optic link, it uses a method known as wavelength-division multiplexing. This allows multiple channels to be transmitted over the same optical fiber, increasing capacity and saving space in cable ducts.