Seminar-Report-on- Optical Fiber Communications

7997 Words Dec 17th, 2012 32 Pages
Table of Content



1.0 Introduction 8

2.0 History of Optical Fiber 9

3.0 Construction of Optical Fiber 12

4.0 Guiding Mechanism in Optical Fiber 13

5.0 Basic Components of OFC 15

5.1 Transmitter 15

5.2 Fiber 15

5.3 Receiver 15

5.4 Process 16

6.0 Principle of optical transmission 16

6.1 Refractive Index 16

6.2 Snell’s Law 17

6.3 Critical Angle 17

6.4 Total Internal Reflection 18

6.5 Acceptance Cone 19

6.6 Numerical Aperture 21

7.0 Advantage of optical fiber communication 23

7.1 Advantage of optical fiber communication 26

8.0 Dispersion 28

8.1 | Material | 29 | 8.2 | Mode | 29 | 8.3 | Waveguide | 29 | 9.0 Attenuation 30

9.1 Absorption loss
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This simple experiment, illustrated in Figure, marked the first research into guided transmission of light.

In the same year, Alexander Graham Bell developed an optical voice transmission system he called the photo phone. The photo phone used free-space light to carry the human voice 200 meters. Specially placed

mirrors reflected sunlight onto a diaphragm attached within the mouthpiece of the photo phone. At the other end, mounted within a parabolic reflector, was a light sensitive selenium resistor. This resistor was connected to a battery that was, in turn, wired to a telephone receiver. As one spoke into the photo phone, the illuminated diaphragm vibrated, casting various intensities of light onto the selenium resistor. The changing intensity of light altered the current that passed through the telephone receiver which then converted the light back into speech. Bell believed this invention was superior to the telephone because it did not need wires to connect the transmitter and receiver. Today, free-space optical links find extensive use in metropolitan applications.

The first practical all-glass fiber was devised by Brian O'Brien at the American Optical Company and Narinder Kapany (who first coined the term 'fiber optics' in 1956) and colleagues at the Imperial College of Science and Technology in London. Early all-glass fibers experienced excessive optical loss, the loss of the