Fiber Optics in Telecommunication
Because of its advantages over electrical transmission, optical fibers have largely replaced copper wire communications in core networks in the developed world.
Fiber–optic cable is used by many telecommunications companies to transmit telephone signals, internet communication, and cable television signals, sometimes all on the same optical fiber.
The optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. Although fibers can be made out of transparent plastic, glass, or a combination of the two, the fibers used in long–distance telecommunications applications are always glass, because of the lower optical loss.
Both multi–mode and single–mode fibers are used in communications, with multi–mode fiber used mostly for short distances (up to 500 m), and single–mode fiber used for longer distance links. Because of the tighter tolerances required to couple light into and between single–mode fibers, single–mode transmitters, receivers, amplifiers and other components are generally more expensive than multi–mode components.