13-08-2014, 10:29 AM
Seminar Report On Introduction To Optical Fiber Communication
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Abstract
This paper is about the most efficient and less expensive way of communication that is none other than a fiber optics. In this paper history of fiber optics, construction of optical fiber, merit and demerits are explained briefly. Different types of media are used for the purpose of communication like co-axial cable, microwave link, pigeon, smoke signal, but most efficient of them is fiber optics that works on the principle of total internal reflection.
INTRODUCTION
The evidence of communication has been found from ancient time. To address the people, in the king’s era drum beat was used. To send a message to far off town people used a trained pigeon. But they were slow mode of communication and the chance for the error is always there. Necessity is the mother of invention and mankind started to ponder on the means of communication that are more efficient and consumes less time. The first successful attempt was made by Graham Bell by using a copper wire. After wards Marconi did a mysterious job with the invention of radio and laid the foundation of wireless system. Communication is nothing just the interaction of two terminals by using some communication means. With the help of electromagnetic wave our world has changed into global village.
We can’t confine to the electromagnetic waves whose data carrying capacity is small. We have to surpass it. In order to do this more experiments were performed and scientist explore new mean of communication. To send signal to a long distance a carrier signal is multiply with the original signal and with the help of it we can able to send signal to a long distance. Modulation is just like our vehicles, if we want to travel a long distance just like hundreds of miles, we can’t do it on foot we have to take help of some fast moving thing which lead us toward our destination. Modulation is just like that moving body.
In the 20th century some scientists started to use light as a data carrier. They found an interesting application that light has some bending properties
HISTORY OF OPTICAL FIBER
The history of fiber optic lay in ancient time. About 2000 year ago Romans covert the known glass the time-glass into fiber and used it to decorate and lavish their homes. Optical telescope was invented in 1609 by a renewable scientist named as ‘Galileo’, In 1626 Snell proposed law of refraction which is basic principle of optical fiber. On the basis of it Newton invented reflection telescope in 1668.The first device based on the phenomenon of light is made by French scientist in 1790 that was named as “semaphores”. It was a tower type device with abeam mounted on it
THE GENERAL SYSTEM
An optical fiber system is used just like ordinary communication system that is to send information from one place to another. Every communication needs a sender and a receiver and the channel or a path to send a message from one place to another. In Electrical transmission the electrical signal is use to convey message from one place to another. To send an electrical signal we have to change it into some form just like if we want to travel voice over electrical line we convert it into electrical wave so that it can travel and decode at the receiver end.Medium can be any wire coaxial cable or a radio link through which we can send message without using any physical structure. [10]
And signal is again converted to original form by using transducer and then forwards it to the receiver. But the important aspect is that due to material properties signal suffer from loss and attenuate due to atmospheric condition, interference and material characteristics. Due to this fact we have to keep safer distance between the sender and the receiver. For the long communication we have to place repeater and amplifier at the safer distance so that signal suffers from less attenuation. And this link also increase signal strength
ADVANTAGES OF OPTICAL FIBER
Communication carried out with the help of optical fiber has enormous number of advantages. The more research in the optical fiber yields many more facilities and make it much better than all other medium especially due to its data carrying capacity.
Some of the merits of fiber optics is given below.
BROAD BANDWIDTH
Broadband communication enhanced a lot using fiber optics which includes audio video transmission. Text and any data can be formulated, modulated and demodulated at the output end. Around 300, 00, 00 and 90,000 TV channel can be transmitted over one fiber. Metallic system has frequency in the range of 20 MHz while fiber has high frequency from 1013 to 1016 . In the year 2000 the optical fiber bandwidth multiply of the distance was 5000 GHz Km while the ordinary cable has 100 MHz per km. Now by using multiplexing technique of different wavelength on the same fiber we can increase the data rate.[12]
SMALL SIZE AND WEIGHT
Optical fiber has extremely small size nearly equal to human hair. They have such a small diameter that even coating doesn’t matter to increase the size of optical fiber. So for the transmission in space and control of air craft by using fiber increase the efficiency of optical fiber which is much smaller than ordinary copper cable. Due to its smaller size it can be buried under ground and under the sea with the glass coated on it. But the weight of optical fiber including the coated is much less than copper.
ELECTRICAL ISOLATION.
Optical fiber are very thick usually not more than the human hair so it has to be protected by placing a coat over the optical fiber just like glass or a plastic polymers that are insulator in nature due to which it has no effect of interference and earth loop problem. So in the areas where there is a danger of electrical short circuiting optical fiber can be used which have no effect of Electrical hazard and no arching
SYSTEM RELIABILITY AND EASE OF RADIATION
Optical fiber has small loss due to which it can be used for a long distance communication without using routers. So the number of line boaster required is small which is used to amplify the signal. Optical fiber lifetime period is much higher than the ordinary cable like 20-30 years
HIGH INSTALLATION CHARGES
The device used in the optical fiber like laser, photo diode, couplers and transducer are much expensive so the installation of optical fiber requires high cost. Highly qualified experts are needed to join these cables due to which installation charges is high.
FRAGLITY
Optical fibers are more fragile than the copper wire that can be rotated and require a much higher coating to save themselves from the atmosphere while copper wire just has plastic coated on it. But optical fiber has much more advantages so it is an important content of communication.
CONCLUSION
Optical fiber is the best medium for the communication with the small ratio of losses and high signal to noise ratio. The facts make it clear that it is much better than the copper wire