Fiber Optic

Phys 221

Optics and Waves

Instructors: Ibrahim GUNAL, S. KAAN yerlÐ"±

By -12-

Ozge AKTAS, Laureta CANGA, Sule Ozturk

1435536 1527498 1490119

Table of contents

1. Introduction......................................................1

2. History of light as a taransmeter........................2

3. type of fiber optic cablesвЂ¦Ð²Ð‚¦.5

3.1 Types according to index….. 5

3.2 Types according to modes…..6

A. Multimode fibers…6

A1.Multimode Step-index Fiber…6

A2.Multimode Graded-index Fiber….7

B. Single mode fiber….8

4. TYPES OF FIBER OPTIC CABLESвЂ¦Ð²Ð‚¦.9

4.1Tight-Buffered CableвЂ¦Ð²Ð‚¦.10

4.2Loose-Tube Cable….11

5. HOW DOES AN OPTICAL FIBER TRANSMIT LIGHT?.....12

6. . APPLICATIONS …..20

7.ADVANTEGES and DISADVANTAGES…..23

8. REFERENCES…..26

1.INTRODUCTION

In the recent years it has been apparent that fiber optic cables are replacing copper wire and the other communication devices. The most important difference of fiber optic cables from other communication enviroment is high velocity in the communication of sound, data and image. Thanks to fiber optic cables that is a latest technique to receive and transfer of signals, ten million phone call and ten thousand television channel can span on only one fiber. In addition to communication, fiber optic is used in the medicine, industry of defence and automotive. The basic sutructure of fiber optic cables include 3 different parts core , cladding and jacket. Also it has different combinations so different types.

Fiber optics is the contained transmission of light through long fiber rods of either glass or plastics. The light travels by a process of internal reflection. The core medium of the rod or cable is more reflective than the material surrounding the core. That causes the light to keep being reflected back into the core where it can continue to travel down the fiber. Fiber optic cables are used for transmitting voice, images and other data at close to the speed of light.

2. HISTORY: The road toward fiber technology

The idea of having light guided through bent glass is not new or high tech. Leonardo DaVinci (1452-1519) actually mentioned such a means for guiding light in one of his notebooks. However, he has not been able to verify this assertion.

In 1854, John Tyndall (1820-1893) demonstrated to the Royal Society that light could be conducted through a curved stream of water, proving that a light signal could be bent.

In 1880, Alexander Graham Bell (1847-1922) invented his 'Photophone', which transmitted a voice signal on a beam of light. Bell focused sunlight with a mirror and then talked into a mechanism that vibrated the mirror. At the receiving end, a detector picked up the vibrating beam and decoded it back into a voice the same way a phone did with electrical signals. Many things -- a cloudy day for instance -- could interfere with the Photophone, causing Bell to stop any further research with this invention.

In 1880, William Wheeler invented a system of light pipes lined with a highly reflective coating that illuminated homes by using light from an electric arc lamp placed in the basement and directing the light around the home with the pipes.

In 1888, the medical team of Roth and Reuss of Vienna used bent glass rods to illuminate body cavities.

In 1895, French engineer Henry Saint-Rene designed a system of bent glass rods for guiding light images in an attempt at early television.

In 1898, American David Smith applied for a patent on a bent glass rod device to be used as a surgical lamp.

In the 1920's, Englishman John Logie Baird and American Clarence W. Hansell patented the idea of using arrays of transparent rods to transmit images for television and facsimiles respectively.

In 1930, German medical student, Heinrich Lamm was the first person to assemble a bundle of optical fibers to carry an image. Lamm's goal was to look inside inaccessible parts of the body. During his experiments, he reported transmitting the image of a light bulb. The image was of poor quality, however.

In 1954, Dutch scientist Abraham Van Heel and British scientist Harold. H. Hopkins separately wrote papers on imaging bundles. Hopkins reported on imaging bundles of unclad fibers while Van Heel reported on simple bundles of clad fibers. He covered a bare fiber with a transparent cladding of a lower refractive index. This protected the fiber reflection surface from outside distortion and greatly reduced interference between fibers. At the time, the greatest obstacle to a viable use of fiber optics was in achieving the lowest signal (light) loss.

In 1961, Elias Snitzer of American Optical published a theoretical description of single mode fibers, a fiber with a core so small it could carry light with only one wave-guide mode. Snitzer's idea was okay for a medical instrument looking inside the human, but the fiber had a light loss of one decibel per meter. Communications devices needed to operate over much longer distances and required a light loss of no more than 10 or 20 decibels (measurement of light) per kilometer.

In 1964, a critical (and theoretical) specification was identified by Dr. C.K. Kao for long-range communication devices, the 10 or 20 decibels of light loss per kilometer standard. Kao also illustrated the need for a purer form of glass to help reduce light loss.

In 1970, one team of researchers began experimenting with fused silica, a material capable of extreme

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