This document provides an overview of optical fiber communications. It begins with an introduction to optical fibers and their construction. It then discusses the principles of total internal reflection that optical fibers use to transmit light signals. The document outlines different fiber optic configurations like single-mode and multi-mode fibers. It describes common uses of fiber optics in communication systems, cable television, and imaging. The document concludes by discussing advantages of optical fibers like large bandwidth, noise immunity, safety, and reliability.

1. C B KORE POLYTECHNIC
CHIKODI
Topic :OPTIC FIBRE COMMUNICATIONS
BY: VANDANA DESAI
V sem EC
SHARVANI MUSANDI
V sem EC

2. Brief Flow of the Presentation.
1. Introduction
2. What are Optical Fibers?
3. Construction of optical fiber
4. Working principle
5. Fiber optic configuration
6. Working of optical fiber
7. Fiber optics in uses
8. Advantages of Optical fiber
9. Future of fiber optics

3. Optical fiber
 INTRODUCTION
 Fiber optics (optical fibers) are long, thin strands of very pure glass
about the diameter of a human hair. They are arranged in bundles
called optical cables and used to transmit light signals over long
distances.
 CAUSES FOR THE CREATION OF THE OPTICAL FIBER-----
Man’s HUNGER
 Lastly optical fiber’s were invented to satisfy the Man’s hunger for
communication

4. What are optical fibers?
 Fiber optics = Fiber + optics
 in essence = Light is guided in optical
fiber.
 Fiber = Extremely pure glass(silica)
or plastic
 Speed= current record
15.5tbps
Total internal reflection

5. Construction of optical fiber
 Core-thin glass center of
fiber where light travels.
 Cladding-outer optical
material surrounding the
core.
 Buffer coating-plastic
coating that protects the
fiber.

6. TOTAL INTERNAL REFLECTION
When light travelling in an optically dense
medium hits a boundary at an angle larger
than the "critical angle" for the media, the
light will be completely reflected. This is called
total internal reflection.
Fiber optic cables use total internal
reflection inside the optical fiber.

7. TOTAL INTERNAL REFLECTION

8. FIBRE OPTIC CONFIGURATION
SINGLE MODE OPTICAL FIBER
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.
Single-mode fiber’s smaller core (<10
micrometers) necessitates more expensive
components and interconnection methods
Allows much longer, higher-performance
links.

9. MULTI MODE OPTICAL FIBRE
This type of optical fiber are 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.
Multi-mode fiber introduces multi-mode
distortion which often limits the bandwidths
and length of the link.
Furthermore, because of its higher dopant
content, multimode fiber is some what more
expensive.

10. Step Index fibre
 The refractive index of core is constant
 The refractive index of cladding is constant
 The refractive index of cladding is slightly
lower than that of core

11. Graded index fibre
 Refractive index of core decreases smoothly
from the centre to the outer edge
 Refractive index of cladding is constant

13. Working of optical fiber
Light Transmission

14. Fiber Optics in uses
 Communication Systems
 Cable Television
 Imaging
 Additional Uses

15. Communication Systems
 Networking and telecommunication are two
areas where fiber-optic cables are ideal signal
conductors.
 well-matched for both long-distance and
short-distance communication
 Individual glass fibers can transmit
independent light pulses on multiple
wavelengths, which allows each strand to
carry simultaneous streams of data on various
channels.

16. Cable Television
 Usage of fiber-optic cables in the cable-
television industry began..
 Advantages of using fiber optic in cable
television
 Fiber-optic cable allows cable providers to
offer more customized service

17. Imaging
 In a medical setting it is used in
endoscope
 In other environments, where
the device is also called a bore
scope or fiberscope

18. Additional Uses
 Computer and Internet technology has
improved due to optical fibers' enhanced
transmission of digital signals.
 fiber-optic signals stay strong longer, requiring
less power over time to transmit signals than
copper-wire systems.

19. ADVANTAGES
 Much higher bandwidth
 Thousands of channels can be multiplexed together over one
strand of fiber
 Immunity to noise
 Safety
 Security
 Attenuation
 Reliability
 Size

20. Advantages of optical fiber
The optical fiber has
following advantages over
twisted -pair and coaxial
cable.
• Resistance to noise
• Huge bandwidth
• Higher signal carrying
capacity

21. The Future of Fiber Optic
 As with all technology current fiber optics does have a
theoretical limit. The idea that transferring data through light
was at one time thought to be limitless, however laboratory
tests are showing that we are quickly reaching the ceiling that
fiber optics offer us.
 Small improvements are on the horizon modifying the way
signals are encoded, which would carry us a few extra years.
 The next big breakthrough is still deep in development
though, and little is known what the future holds.

22. • Conclusion:
This is the greatest discovery that man have done in the field of communication.
Modern communication will not be possible without the invention of fiber optics. These small
cables touch every facet of our lives, mostly without us even noticing.
REFERENCE:
Wikipedia – Internet.
Freud enrich Craig. How Fiber Optics Work. n.d. Date Retrieved 30 Nov.
2010. http://communication.howstuffworks.com/fiber-optic-
communications/fiber-optic2.htm
Maddox Nathanial. What Is Fiber Optic Cable Used for? n.d. Date
Retrieved 14 Nov. 2010 http://www.ehow.com/about_4895491_what-fiber-
optic-cable-used.html
Murphy D. 40Gbps internet connection installed in Swede's home. 13 July
2007. Date Retrieved 25 Nov. 2010.
http://www.engadget.com/2007/07/13/40gbps-internet-connection-installed-
in-swedes-home/
TELUS' Network Technology. n.d. Date Retrieved 25 Nov. 2010.
http://about.telus.com/networktechnology/index.html
THANK YOU