FIBER OPTICS

Fiber-optic lines are strands of optically pure glass as thin as a human hair that carry digital information over long distances  sends information coded in a beam of light down a glass or plastic pipe
Fiber-optic cables carry information between two places using entirely optical (light-based) technology
A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

Fiber optics has several advantages over traditional metal

Fiber optic cables have a much greater bandwidth than metal cables. This means that they can carry more data.

Fiber optic cables are less susceptible than metal cables to interference.

Fiber optic cables are much thinner and lighter than metal wires. 

Data can be transmitted digitally (the natural form for computer data) rather than analogically.

Creating the optical signal involving the use of a transmitter, relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak, receiving the optical signal, and converting it into an electrical signal.

Total Internal Reflection

A ray of light, incident upon the interface between two transparent optical materials having different indices of refraction, will be totally internally reflected (rather than refracted)

 if

(1) the ray is incident upon the interface from the direction of the more dense material and

(2) the angle made by the ray with the normal to the interface is greater than some critical angle, the latter being dependent only on the indices of refraction of the media

Total internal reflection between two transparent optical media results in a loss of less than 0.001 percent per reflection;

The speed of light in matter is less than the speed of light in air, and the change in velocity that occurs when light passes from one medium to another results in refraction.

Single Fibers

Single fibers, the simplest form of fiber optics, can be used to conduct light and images to and from small regions.

Single fibers are readily available in diameters from about 0.020 to 2.0 millimeters,

Multifibers can be fused together to form image conduit, an actual image carrier. Resolution is limited by the size and packing density of the individual fibers as well as by the care exercised in packing the multifibers.

Image conduit has little or no flexibility but can be bent with heat to conform to almost any desired path. The bending radius for a half-inch-square conduit

Multi-mode Each optical fiber in a multi-mode cable is about 10 times bigger than one in a single-mode cable.

A number of fiber optic configurations for a new class of demand assignment multiple-access local area networks requiring a physical ordering among stations are proposed.

The configurations proposed for the data sub network are based on the linear, star, and tree topologies.

fiber optic connectors are plugs or so-called male connectors with a protruding ferrule that holds the fibers and aligns two fibers for mating adapter to mate the two connectors that fits the securing mechanism of the connectors

The nose piece is spring loaded and was pushed back when the connector was inserted into a mating adapter. The fiber stuck out into a drop of index matching fluid on a plastic lens

Features of good connector design

Low insertion loss, High return loss (low amounts of reflection at the interface), Ease of installation, Low cost, Reliability, Low environmental sensitivity, Ease of use

Fiber optic connectors must align microscopic glass fibers perfectly in order to allow for communication