1. 1. Shantilal Shah Engineering College, Bhavnagar INSTRUMENTATION AND CONTROL ENGINEERING ( SEMESTER 1 ) 1 Sidsar Campus, P.O. Vartej, Bhavnagar-364060 Phone: 0278-2445509, 2445767 Fax: 0278-2445509 Website: http://www.ssgec.ac.in/
2. 2. 2 OUR GROUP Members : 1. Jitin J Pillai 2.Dodiya Siddhraj 3.Kaneriya Yash 4.Dodiya Parth 5.Tripathi Vishal
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4. 4. 4 INTRODUCTION Optical Fibers are hair-thin, transparent strands through which light can be transmitted. A group of many such optical fibers constitute a Optical Fiber Cable.
5. 5. 5 CONSTRUCTION The main parts of an optical fiber are : Core thin glass center of the fiber where light travels. Cladding outer optical material surrounding the core. Buffer Coating plastic coating that protects the fiber. Other protective coatings.
6. 6. 6 PRINCIPLE TOTAL INTERNAL REFLECTION is the main principle behind the working of an optical fiber. For T.I.R., conditions are satisfied : Light is incident on the walls of the cable at an angle greater than the critical angle. The optical-fiber core is clad (coated) by a lower density glass layer.
7. 7. 7 FIBER TYPES 1. Plastic core and Plastic cladding 2. Glass core with Plastic cladding PCS (Plastic-Clad Silicon) 3. Glass core and Glass cladding SCS (Silica-clad silicon) 4. Under research: Zinc-chloride (non-Silicate) 1000 time as efficient as glass ON THE BASIS OF MATERIAL :
8. 8. 8 ON THE BASIS OF MODE OF PROPAGATION : 1. Singlemode Fiber : Only one path for the propagation of light. The core is made very small (about 7-10 m). 2. Multimode Fiber : More than one paths for the propagation of light. Core is larger in diameter (about 20-100 m).
9. 9. 9 ON THE BASIS OF INDEX PROFILE 1. Step-Index Fiber : Refractive index of the core as well as the cladding is uniform. Light rays propagate in the form of meridional rays, i.e. they follow a zigzag path and, for every reflection they will cross the fiber axis. 2. Graded Index Fiber (GRIN Fiber): Refractive index of the core is not uniform, while that of the cladding is uniform. Light rays propagate in the form of skew rays, i.e. they follow a helical path and will never cross the fiber axis.
10. 10. 10 FIBER CONFIGURATIONS I. Singlemode Step-Index Fiber (SMSI Fiber) Single-mode step-index Fiber n1 core n2 cladding no air Light ray Index of refraction
11. 11. 11 II. Multimode Step-Index Fiber Multimode step-index Fiber n2 cladding n1 core no air Index of refraction
12. 12. 12 III. Multimode Graded Index Fiber Variable n Index profile Multimode graded-index Fiber Index of refraction
13. 13. 13 ADVANTAGES OF OPTICAL FIBER Capacity: much wider bandwidth (10 GHz) Crosstalk immunity Immunity to static interference Lightning Electric fields Florescent light Higher environment immunity Weather, temperature, etc. Safety: Fiber is non-metallic. No explosion, no shock Lasts longer. Security: tapping is difficult Economics: Fewer repeaters Low transmission loss (dB/km) Fewer repeaters Less cable Remember: Fiber is non-conductive Hence, change of magnetic field has No impact!
14. 14. 14 DISADVANTAGES OF OPTICAL FIBER Higher initial cost in installation Interfacing cost Less strength Lower tensile strength Remote electric power More expensive to repair/maintain Tools: Specialized and sophisticated
15. 15. 15 APPLICATIONS In Telecommunications to transfer data. In Local Area Networks to share internet connections. In Cable TV and CCTV. In Optical Fiber Sensors. In Endoscopy to view internal body organs. In decoration.
16. 16. 16 Input Signal Coder or Converter Light Source Source-to-Fiber Interface Fiber-to-light Interface Light Detector Amplifier/Shaper Decoder Output Fiber-optic Cable Receiver OPTICAL FIBERS ARE USED IN TELECOMMUNICATION Transmitter
17. 17. 17 OPTICAL FIBERS ARE USED IN ENDOSCOPIC SURGERY
18. 18. 18 THANK YOU