Introduction Fiber optic

Optical communication systems date back two centuries, that was begin from "optical telegraph" that French engineer Claude Chappe invented in the 1790s. His system was a series of semaphores mounted on towers, where human operators relayed messages from one tower to the next. It beat hand-carried messages hands down, but by the mid-19th century was replaced by the electric telegraph, leaving a scattering of "Telegraph Hills" as its most visible legacy. And Alexander Graham Bell patented an optical telephone system, which he called the Photophone, in 1880, but his earlier invention, the telephone, proved far more practical. He dreamed of sending signals through the air, but the atmosphere didn't transmit light as reliably as wires carried electricity. In the decades that followed, light was used for a few special applications, such as signalling between ships, but otherwise optical communications, like the experimental Photophone Bell donated to the Smithsonian Institution, languished on the shelf.

Fiber optic are essentially transparent rods of glass or plastic and it not flexible like metal cable. Diameter core optic not more 1 mm, it can transmission many information and not low loss information.

Core optical had protect by coating and cladding. Function core optical there is transmission for light wave, and core optical have refractive more better than coating and cladding because material it from transparent rods of glasses or plastic, diameter it about 2-125 μm (depend on optic type). Function cladding as fiber bodywork packer encircling core and refractive is low. Refractive at cladding low more than core, that is to make light in core keep focus until light receiver. Material of cladding that same with core but diameter more bigger than core between 5-250 μm (depend on optic type). Coating function is protect core and cladding, made from elastic plastic.

Difference of refractive of materials core and cladding, also damping or loss become important attention an optical fiber transmission system. Refractive useful in determining light coupling from optical source and useful in determining crept path of light variation of optical fiber. For the delivery light wave used infra-red area with wavelength 850-1600 μm. Damping of loss will have an in with determination apart maximum before repair of signal, smaller generated damping hence progressively the optical transmission the system is goodness.