ABOUT F/O

ADVANTAGES OF FIBER OPTIC
Fibre Optic signal transmission offers many advantages over existing metallic links. Some of these are:
1. Large Bandwidth

Fiber optic offers very high bandwidths as compared to copper wire. The bandwidth of a fiber optic cable is between100Mhz to 1000 MHz as compared to a copper wire, which can handle only 3 to 20 MHz. This large bandwidth allows many applications and uses of fiber optic. For example, a video signal has a bandwidth of 5 MHz. It is, therefore, possible to send up to 20 - 200 video signals on a single fiber optic cable. This is impossible with copper wire. In fact, by using digital compression techniques you could modulate up to 500 - 1000 video signals on a single F/O cable.
2. No Interference
Unlike coaxial cable which uses electric currents, fiber optic uses light making it immune to any type of interference

No EMI interference - As light is the medium of transmission, fiber optic cable does not pick up Electro Magnetic Interference (EMI). EMI is the biggest source of problems with the co-axial cable. Double images, moving lines, horizontal bands, and picture snow in a video picture are due to EMI. All these are eliminated with the use of fiber optic.

No ground loop currents - Ground loop current is caused when the two ends of the cable are not grounded to the same potential. This difference in potential causes a current, which is usually seen as moving lines on a video picture. Fiber optic do not use electricity and therefore ground loop currents are impossible.

No power interference - Voltage has any effect on the light beam. It is therefore irrelevant whether the fiber optics passes next to 240VAC or 10000 VAC, or close to a powerful transmitter. This has no effect on the light beam in the fiber optic cable.

Immune to lightning - Even lightning that hits a centimeter away a fiber optic cable cannot induce any voltage in it.

Fiber optic cables are very small and low in weight. It is therefore much easier to lay fiber optic cable compared to metallic cable, which can be heavy and bulky.

4. Security of information
It is impossible to tap into a fiber optic cable without physically intercepting the signal, in which case it is detectable at the receiving end.
DISADVANTAGES OF FIBER OPTIC
1. Cost of fiber optic cable.Fiber optic is still quite expensive as compared to the copper wire, though the prices are coming down rapidly. This disadvantage could be made into an advantage by using innovative cabling and installation methods. In co-axial cable, a single cable has to run from the camera point to the control room.

As fiber optic has large bandwidths, it is possible to multiplex many video signals on a single fiber optics cable and thereby reduce cabling and installation cost. For example in the Ring Method, a single fiber optic cable runs all over the site, the cameras are connected to this cable, and the video signals are multiplexed at different frequencies.
2. Termination
The termination of fiber optic cable is complex and requires special tools, better precision of workmanship and is more time consuming and therefore more expensive. Fiber optic cable has a very small diameter and requires specialized tools to align the cables correctly and then join them. The glass in the fiber optic core has to be grounded flat first to ensure correct alignment for proper and smooth termination. This looks complex, but many tools are available to ensure that the termination, etc. can be achieved more easily.
3. Cable laying
The center core of a fiber optic cable is made of glass. Extra precaution is required during cabling. Stretching of cable should be avoided as the glass core may crack. In addition, the cable bending is a major problem. Sharp bends could crack the cable but also the light beam bouncing off the glass core may not handle the bend and the light beam may ‘escape out’ of the core. Most cable manufacturers provide permissible bending angles.
There is no denying that the advantages definitely outweigh the disadvantages. There are more benefits to using fiber optic. It is because of these facts the usage of fiber optic is growing daily.