Optical communication.pptx

Optical communication introduction

1. Optical Fiber Communication Dr. M V Raghavendra, Professor, Department of Electronics & Communication Engineering

2. Out Line Introduction to optical fiber communication Ray Optics Principle of Optical Communication Structure of Optical fiber Classification of optical fibers Optical Communication Block Advantages Disadvantages Applications References

3. Introduction to Optical Communication Optical communication, is  communication  at a distance using  light  to carry information. It can be performed visually or by using  electronic devices .  Optical Communication is the most modern mode of wired communication. Optical communication is also the youngest mode of communication. However its capabilities supersede all other modes of communication. Before optical communication the most of the communication was in radio and microwave domain which has frequency range orders of magnitude lower than the optical for the electromagnetic spectrum.

4. Ray Optics: basic laws 3 3

5. Snell's Law

6. Refractive index Refractive index of a medium is represented by n. It is defined as ration of velocity of light in free space to velocity of light in the given medium. I.e. * The index varies with a number of parameters, such as wavelength and temperature.   Air 1.0 Water 1.33 Magnesium fluoride 1.38 Fused silica (SiO2) 1.46 Sapphire (Al2O3) 1.8 Lithium niobate (LiNbO3) 2.25 Indium phosphide ( InP ) 3.21 Gallium arsenide (GaAs) 3.35 Silicon (Si) 3.48 Germanium ( Ge ) 4.0 Refractive indices of some materials Rarer Medium: A medium in which refractive index is less Dancer Medium: A medium in which refractive index is high.

7. Rarer medium Dancer medium Ray Optics Normal Interface

8. Rarer medium -   Dancer medium -  

9. Critical angle

10. Rarer medium -   Dancer medium -   Total- total energy Internal – same medium Reflection (TIR) Principle of Optical communication – Total Internal Reflection

11. Total internal reflection

12. Structure of Optical fiber Structure of Optical fiber cable Core- A medium which has high refractive index ( ) Cladding- A medium which has low refractive index ( ) Buffer coating - Used for mechanical protection  

13. Core Cladding Cladding Core Refractive Index Profile Core Cladding Cladding Core Refractive Index Profile Output Pulse Input Pulse Core Cladding Cladding Core Refractive Index Profile Output Pulse Input Pulse Classification of Optical Fibers

14. Optical Fiber Communication Block Diagram

15. Fiber Optic Data Transmission Systems Fiber optic data transmission systems send information over fiber by turning electronic signals into light. Light refers to more than the portion of the electromagnetic spectrum that is near to what is visible to the human eye. The electromagnetic spectrum is composed of visible and near-infrared light like that transmitted by fiber, and all other wavelengths used to transmit signals such as AM and FM radio and television.

16. Advantages Low Attenuation Very High Bandwidth (THz) Small Size and Low Weight No Electromagnetic Interference Low Security Risk High speed Distance of transmission Cheap Long life span

17. Limitations Transmission over fiber is limited by Attenuation, Distortion Scattering and Dispersion. Multimode fibers may experience Multimode dispersion: The delayed rays cause pulse spreading Chromatic dispersion: Individual wavelengths may travel at different speeds. Dispersion creates an inherent operational limit defined as a bandwidth-distance product (BDP). Difficult to splice.

18. Applications The application and uses of optical fiber can be seen in: Medical Industry – Surgery and Dentistry Communication Defense Industries Broadcasting Lighting and Decorations Military and Aerospace Computer networks Mechanical Inspection TV cables Internet Remote Sensing

19. References [1] M. Artiglia , “Mode field Diameter measurements in single-mode optical fibers,” J. Light wave Tech. Vol. 7, no. 8, pp. 11391152, 1989. [2] J. A. Buck, “Fundamentals of Optical fibers,” John Wiley & Sons, 1995. [3] J. Sakai, and T. Kimura, “Bending loss of propagation modes in arbitrary-index profile optical fibers”, Applied Optics vol. 17, no. 10, pp 1499-1506, May 1978 [4] A. W. Snyder and J. D. Love, "Optical Waveguide Theory," Chapman and Hall, 1983. [5] K. Petermann, “Microbending loss in mono mode fibers,” Electron. Lett ., vol. 20, no. 3, pp. 107- 109, 1976. [6] S. E. Miller and I. P. Kaminow , Eds., “Optical Fiber Telecommunications II,” Academic Press, 1988. [7] J. Sakai and T. Kimura, “Birefringence and Polarization Characteristics of Single-Mode optical Fibers under Elastic Deformations”, IEEE Journal of Quantum Electronics , vol. QE-17, no. 6, [8] C. D. Poole, N. S. Bergano , R. E. Wagner, and H. J. Schulte, “Polarization Dispersion and Principal States in a 147-km Undersea Lightwave Cable”, Journal of Light wave Technology , vol. LT-6, no. 7, pp 1185-1190, July 1988. pp 1041-1051, June 1981. [9] D. Marcuse, “Theory of Dielectrical Optical Waveguides, Second Ed.,” Academic Press, 1991.

20. Thank You