What is a fibre optics? How it is used for data communication, what are the advantages of fibre optics?

Ans: Fibre Optic Cable:

                      Traditionally, most phone line transmit data electrically over wires made of metal, usually copper. These metal wires had to be protected from water and other corrosive substances. Fiber optics technology eliminates this requirement. Instead of using electricity to send data, fibre optics uses light pulses: each 'on' pulse represents one bit. The cables are made of glass fibres, each thinner than a human hair, that can guide light becomes for kilometres. 

                  An optical fibre consist of an inner cylinder of glass, called the core, which the actual propagating path for the light. It is surrounded by a a cylindrical shell of glass or plastic of lower refractive indices, called cladding. 

                     The transmission of light is based on the phenomenon of total internal reflection which occurs when light is incident at an interface between two medium of refractive indices i.e core/cladding, at an angle greater than the critical angle. In absence of the sattering defects along the interface total internal reflection is a highly efficient phenomenon and thousands of such relections can occur within a fibre with little loss of light. 

Advantages of Fibre Optic Cable: 

(1) Fibre optics transmits data faster than some technologies. 

(2) The main ingredient in glass is sand and there is an enormous supply of sand in the world as compared to the supply of aluminium and copper. The material is also substantially lighter than wire  cable. 

(3) Photos of light, rather than an electrical current move through the fibre optics. Therefore, there is no chance of spark flash there by making this system safer. 

(4) Since fibre optics carries light pulses, it is not effected by random electromagnetic interference in the environment. Thus they have much lower error rates than normal telephone wires and cables. 

(5) Because  of the absence of current flow through the fibre optics, instruction into the system is also prevented. Confidential information can not be routed to unwanted receivers, nor canfalse information be fed into the data steam.

(6)The transmission losses in fibre optics are much lower than that of the twisted pair wires and coaxial cables. 

(7) Glass is immune to corrosive and oxide  degradation. So fibere - optic cable is more durable than twisted - pair and coaxial cable.