Optical fibre

In this slide i introduced some of the basic concept of optical fibre.

1. OPTICAL FIBRE DEPT . OF ELECTRONICS AND COMMUNICATION By: Saumya Ranjan Behura 1

2. CONTENT Introduction Construction Types of optical fiber Working Charactertics Uses Advantages & Disadvantages Future Scope Conclusion Reference

3. Introduction : An optical fibre is a thin, flexible, transparent fiber that acts as a waveguide, or "light pipe“, to transmit light between the two ends of the fiber . Optical fibers are widely used in fiber -optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. Fibers are used instead of metal wires because signals travel along them with loss less and are also immune to electromagnetic interference. 3

4. Fibers are also used for illumination and are wrapped in bundles so that they may be used to carry images, thus allowing viewing in confined spaces, as in the case of a fiberscope. Optical fiber typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core of phenomenon of total internal reflection which causes the fiber to act as a waveguide.

5. TOTAL INTERNAL REFLECTION: When a ray of light travels from a denser to a rarer medium such that the angle of incidence is greater than the critical angle, the ray reflects back into same medium, this phenomenon is called as TIR. In optical fiber the rays undergo repeated total number of reflections until it emerges out of the other end of the fiber , even if it is bent.

6. Construction : Fiber optic cable consists of a core, cladding, coating, buffer strengthening fibers and cable jacket. CORE : It is the physical medium that transports optical data signals from an attached light source to a receiving device. CLADDING : It is a thin layer that surrounds the fiber core and serves as a boundary that contains the light waves & causes the refraction. COATING: It is a layer of plastic that surrounds the core & cladding to reinforce the fiber core.

7. STRENGTHENING FIBERS : It helps to protect the core against crushing forces and excessive tension during installation. CABLE JACKET : It is the outer layer of any cable.Various colors can be used to designate different application within a network.

8. TYPES OF OPTICAL FIBER : MULTIMODE : Multimode cable has a large diameter core and multi paths of light. It is commonly available in two core sizes : 50 micron and 62.5 micron. It can be used for most general data and voice fiber application. 8

9. SINGLE-MODE : Single mode cable has small glass core and only one pathway of light. It provides 50 times more distance than multi- mode cables. It is used in high bandwidth application and in long-haul network connection spread out over extended areas including televisions .

10. BLOCK DIAGRAM OF OPTICAL FIBER COMMUNICATION:

11. OPTICAL FIBER COMMUNICATION CONSISTS OF THREE MAIN ELEMENTS: 1 . TRANSMITTER Drive circuit drives the light source. Light source converts electrical signal to optical. Fiber flylead is used to connect optical signal to optical fiber. 2 . TRANSMISSION CHANNEL: Optical connector is for temporary non- fixed joints between two optical fiber. Optical splice is used to permanently join two optical fiber.

12. 3 . RECEIVER: Optical signal is applied to the optical receiver. Photo detector converts the optical signal to electrical signal. Signal restorers and amplifiers are used to improve signal to noise ratio of the signal.

13. WORKING : The optical fiber works on the principle of total reflection. Light rays can be used to transmit huge amount of data and travels in straight line. The optical cables are designed such that they bend all the light rays inwards. Light rays travel continuously bouncing off the optical fiber walls and transmitting end to end data.

14. CHARACTERISTICS : WIDER BANDWIDTH : The optical carrier frequency is in the range 10^13 Hz to 10^15Hz. LOW TRANSMISSION LOSS : The fibers having a transmission loss of 0.002dB/km. DIELECTRIC WAVEGUIDE : Optical fibers are made from silica which is an electrical insulator. SIGNAL SECURITY : The transmitted signal through the fibers does not radiate. SMALL SIZE AND WEIGHT : Fiber optic cables are developed with small radii, and they are flexible, compact and lightweight.

15. Uses : Fibers are widely used in illumination application They are used as light guides in medical and other application in some building Optical fiber are used to route sunlight from the roof to other parts of the building

16. ADVANTAGES : Wavelength Frequency Windows Attenuation Dispersion

17. DISADVANTAGES : High investment cost Need for more expensive optical transmitters and receivers More difficult and expensive to splice than wires Fragility   Affected by chemicals Requires special skills

18. COMPARISON BETWEEN OPTICAL FIBER, CO-AXIAL CABLE & TWISTED PAIR CABLE: OPTICAL FIBER CO-AXIAL CABLE TWISTED PAIR CABLE Transmission of signal over a glass fiber. Transmission of signal over inner conductor cable. Transmission of signal over conducting wires. Expensive Moderate expensive Cheapest medium Very high bandwidth Moderate high band- width. Low bandwidth Attenuation is very low. Attenuation is low. Attenuation is very high. Installation is difficult. Installation is fairly easy. Installation is easy.

19. Future scope: All optical communication networks Multi-Terabit optical network Intelligent optical transmission network Polymer optic fibers Improvement in optical amplification Improvements in glass fiber design and component High- Altitude platform

20. conclusion : Fiber optics, a branch of optics dealing with the transmission of light through hair-thin, transparent fibers. A principle called total internal reflection allows optical fibers to retain the light they carry. The development of new optical technique will expand the capability of fiber optic system.

21. REFERENCE : Wikipedia N.S. Kapany , Fiber Optics: Principles and application J.Gower , Optical communication system, 2 nd ed., Prentice Hall https://www.slideshare.net/mobile/manoj_2586/wireless-charging-ppt-45698396

22. THANK YOU !!