Fiber optic uses glass fibers to transmit light signals for communication over long distances. It has advantages over copper cables, including lower signal loss over long lengths. Optical fiber consists of a higher refractive index core surrounded by cladding. Total internal reflection traps light signals inside the fiber for transmission. There are two main types - singlemode fiber for long distance transmission and multimode fiber for shorter campus or building networks. Fiber optic communication has benefits like high bandwidth, low attenuation, and immunity to electromagnetic interference.

1. WHAT IS FIBER OPTIC?
Optical fiber is the fiber of transparent material (usually glass) that allows
transmission of light from one side to the other, and based on a physical
principle called total internal reflection (or total reflection) of the light
beam. the advantages of this method over the transfer of electrical signals in
copper cables, which assumes the signal suffers high as the distance (cable
length) is growing.The first optical fiber created in 1970 by Corning.
Fiber consists of a core (core) and envelope (cladding), both of which are
transparent. The core of refractive index slightly higher than that of the
outer shell, thereby creating a situation in which light rays “trapped” inside
the fiber and move along solicitations or twists. Shell coated with another
thin protective layer (jacket) made of PVC, which aims to protect the shell
from scratches and blows (the light is stuck in this layer only in the inner
glass layers ).
At Optical communications, the fiber optic signals are in the infrared and
there are three main areas of wavelengths: around 850 nm and 1310 nm, or
about 1550 nm.Since laying fiber-optic cables is expensive and complex
operation , optical fiber cable usually contains a few dozen to minimize
fiber optic cable need to be replaced. The use of fiber media is usually in
pairs; One fiber is used to send data and the other to receive the data.

2. Optical fiber divided into two types:
the color is Yellow
Singlemode – fiber which transmitted information singly to prevent
interference and achieve long transmission distances. These fibers can
transmit information over a kilometers. They are especially common
on WAN, between cities countries and underwater cable. Single-mode
fiber communications are usually with 125-micron diameter shell and a
core diameter 9 microns, and are covered with a protective layer
thickness of 125 microns. Such fiber is marked sometimes 9/125/ or
9/125/125.

3. Multimode
The color is Orange.
fiber in which information is transmitted in several ways
simultaneously. This method is quite limited because such fiber There
are several routes which can light switch, so a short light pulse at the
entrance to flatten the output, limiting the rate of fiber
communication and transmission distance. Multimode fibers cheap
and easy to manufacture and therefore are not used in applications
where higher bandwidth is required. These fiber-distance data
transmission using 300 to 500 meters, are commonly used especially in
local area networks within buildings or between adjoining buildings.
Multimode fiber singlemode fibers thicker – their core diameter is
typically 50 or 62.5 microns.Such fiber is marked sometimes 62.5/125
or 50/125

4. Advantage of fiber communication systems:
Very low attenuation compared to copper cables.*
A very large bandwidth, allowing transfer of large amounts of data. *
*The existence of optical amplifiers capable of amplifying a very large
bandwidth.
*Since this optical signal transmission and not electrical, fiber does not emit
electrical electromagnetic radiation and therefore there is greater difficulty
in listening / discover information that goes onto the fiber.
*Optical fiber is not affected by the magnetic field around it and can glueing
near electric cables without fear Data will be affected