The document summarizes Tarun Kumar Matriaya's summer training internship with North Central Railways in Allahabad from June 30 to July 30, 2009. It provides an overview of optical fiber communication and its uses in Indian Railways. Optical fibers have advantages over other communication methods like being thinner, less expensive, and having high bandwidth. Indian Railways uses optical fiber communication to optimize train scheduling, measure speeds, distribute signals, and monitor traffic lights.

1. Presentation By: Tarun Kumar Matriaya EC-B VII SEM Roll No: 0700131202 Industrial Training Seminar

2. Outline Summer Training at North Central Railways, Allahabad from 30 th June, 2009 to 30 th July, 2009. An amazing experience as I got to see, How exactly the communication system works for Indian Railways. Main Objective was to learn Optical Fibre Communication In Railways.

3. Contents Introduction to Indian Railways Introduction to Optical Fibres. Advantages of Optical Fibres. Disadvantages of Optical Fibres. Application of Optical Fibres. Types Of Optical Fibres. Optical Fibre Communication Working of OFC. Use Of OFC in Railways.

4. Introduction to Indian Railways 1832: The first proposal was introduced for having Railways In India. 1853: On April 16 th , at 3:35 pm, The first train left from Bombay to Thane.

5. November 1947 : John Mathai (not formerly designated as Minister to Railways) presents the first Railways budget for Independent India. Present Railway Minister: Dinesh Trivedi.

6. Optical Fibre An optical fibre ( or fiber ) is a glass or plastic fibre that carries light along it’s length. It has two main component layers: A Core & A Cladding. Light is kept in th “core” of optical fibre. Cladding is for the protection of fibre.

7. Advantages of Optical fibre. Thinner than other tubes. Less expensive High Carrying Capacity. Provides a very large Bandwidth Less signal distortion Non- flammable Light Weight

8. Fibre Optic Disadvantages. Expensive over short distance. Very high Installation charges & demands high skills. Adding additional nodes is difficult.

9. Areas Of Application Telecommunication Local Area Networks Cable TV CCTV Optical Fibre Sensors

10. Optical Fibre Construction Core: Thin Glass Center of the fibre where light travels. Cladding: Outer Optical Material surrounding the Core. Buffer Coating: Plastic Coating that protects the Fibre.

11. Material Used. The “Core” , & the lower refractive index “Cladding” , are typically made of high quality silica glass, though they can be both made of plastic as well.

12. Fiber Optic Layers. Consists of three concentric sections. plastic jacket glass or plastic cladding fiber core

13. Mode Of Propagation Two main categories that are used in Fibre Optic Communications are: Multi-mode Optical Fibre Single Mode Optical Fibre

14. Fibre Optic Cable Single-mode Fibre: Carries light pulses along single path. Multi-mode Fibre: Many pulses of light Generated by LED At different angles.

15. Single Mode Fibres Single-mode fibers – used to transmit one signal per fiber (used in telephone and cable TV). They have small cores(9 microns in diameter) and transmit infra-red light from laser.

16. Multi-mode Fibres Multi-mode fibers – used to transmit many signals per fiber (used in computer networks). They have larger cores(62.5 microns in diameter) and transmit infra-red light from LED.

17. Index Profile The boundary between the core and cladding may either be abrupt, in step-index fiber , or gradual, in graded-index fiber .

18. Step-Index A step-index fiber has a central core with a uniform refractive index. An outside cladding that also has a uniform refractive index surrounds the core; However, the refractive index of the cladding is less than that of the central core.

19. Graded-Index In graded-index fiber , the index of refraction in the core decreases continuously between the axis and the cladding. This causes light rays to bend smoothly as they approach the cladding, rather than reflecting abruptly from the core-cladding boundary.

20. Optical Fiber Communication

21. Fiber Optic Communication It is a method of transmitting information from one place to another by sending light through an optical fiber . The light forms an electromagnetic carrier wave that is modulated to carry information.

22. Block Diagram of OFC

23. Total Internal Reflection

24. Use of OFC in Railways. To optimize train scheduling. Speed measurement. Signal distribution by FBG. Traffic light monitoring.