CHAPTER 2-FIBER HISTORY AND CONCEPTS.ppt

1. INTRODUCTION OF FIBER
OPTIC CABLES
CHAPTER 2

2. Light has been used in
telecommunications since early ages,
like candles between ships or huge
torch towers
HISTORY

3. XVIII century (18TH) that French inventor Claude Chappe
demonstrated a practical and more complex light-based
system which he called the semaphore system which
spanned across France.
The concept of this semaphore system was to have special
towers built with pivots on their top that were used to
encode messages according to the mechanical position of
the pivot and the lights that were emitted.
HISTORY

4. (1880) Alexander Graham Bell had patented an optical
telephone device which he called the photo-phone, but his
earlier invention, the electrical telephone was also cheaper
and easier to implement.
HISTORY

5. 1920: John Logie Baird in England and Clarenee W. Hansell
in U.S.A patented the idea of using arrays of hollow pipes
or transparent rods to transmit images for television or
facsimile systems.
John Logie Baird Clarenee W. Hansell
HISTORY

6. 1930: Heinrich Lamm, a Jew medical student in Munich,
reported transmitting the image of a light bulb filament
through a short bundle. He is the first person known to
have demonstrated image transmission through a bundle of
optic fibers. But then, the image he made was of a very
low quality. His patent to his innovation was denied.
Heinrich Lamm
HISTORY

7. 1954
HISTORY

8. 1961
Elias Snitzer
HISTORY

9. Dr. Charles K. Kao
HISTORY

10. 'Father of Fibre Optics' Charles Kao
2009 Nobel Prize in physics for his pioneering work in optical fibre
technology, which can safely be called the reason why we have the
internet.
In the 1960s, Charles Kao created various methods like the
transmission of light -- to combine glass fibres with lasers --
in order to transmit digital data, which laid the groundwork for
the evolution of the Internet. HISTORY

11. HISTORY

12. What are optical fibers
 Thin strands of pure glass
 Carry data over long distances
 At very high speeds
 Fiber can be bent or twisted
CONCEPTS

13. Fiber optic technology
 Sources
 Transmission medium
 Detectors
Fig: The fiber optic communication system
CONCEPTS

14. Sources of light
 Light emitting diodes
 Lasers
CONCEPTS

15. Sources
 Modulate electrical signals into optical signals
 Mostly modulate at 850nm, 1300nm and 1550 nm
 Lasers give high intensity, high frequency light
 LEDs are economical
CONCEPTS

16. Transmission medium
 Optical fiber is replacing copper
 Light is used as the carrier of information
 Much higher data rate
The optical fiber
CONCEPTS

17. Physics of optical fibers
 Index of refraction of material : ratio of speed of
light in vacuum to speed of light in medium
 Refraction of light : bending of light as it travels
from one media to another

18. Refraction of light
 Speed of light changes as it
across the boundary of two
media
 Angles w.r.t normal
CONCEPTS

19. Refraction Indices
 Vacuum…….1.00000 (exactly)
 Air ……1.00029
 Alcohol ......1.329
 Diamond ...... 2.417
 Glass ........ 1.5
 Ice ....... 1.309
 Sodium Chloride (Salt) .... 1.544
 Sugar Solution (80%) ........ 1.49
 Water (20 C) ................ 1.333
CONCEPTS

20. Snell’s Law
 Critical angle: Angle of incidence at which angle of
refraction = 900
CONCEPTS

21. Total internal reflection
 Trapping light in the fiber
CONCEPTS

22. Fibers can be bent!!
Fig: Illustration of total internal reflection
CONCEPTS

23. Types of optical fibers
 Single mode
 only one signal can be transmitted
 use of single frequency
 Multi mode
 Several signals can be transmitted
 Several frequencies used to modulate the signal
CONCEPTS

24. Losses in optical fibers
 Attenuation loss
 Dispersion loss
 Waveguide loss
CONCEPTS

25. Splices and Connectors
 To connect to fibers mechanically or by fusion
 Lot of signal loss possible
 Very accurate alignment necessary
 Most important cost factor
 Now being replaced by optical amplifiers
CONCEPTS

26. Optical Receivers
 Must be very sensitive
 Capable of picking up and amplifying signals of
nanowatts
 Photodiodes and phototransistors
 These devices get ‘turned ON’ by light
 Produce photocurrent
CONCEPTS

27. Advantages of optical fibers
 Can carry much more information
 Much higher data rates
 Much longer distances than co-axial cables
 Immune to electromagnetic noise
 Light in weight
 Unaffected by atmospheric agents
CONCEPTS

28. Tools and Equipment for Fiber
Optics Implementation
Fiber Optic Strippers
Use to remove the
protective polymer
coating around optical
fiber in preparation for
fusion splicing

29. Tools and Equipment for Fiber
Optics Implementation
Fiber Cleaver
a tool that holds
the fiber under low
tension, scores the
surface at the proper
location, then applies
greater tension until
the fiber breaks.
Good cleavers are
automatic and produce
consistent results,
irrespective of the
operator.

30. Tools and Equipment for Fiber
Optics Implementation
Fiber Optics Wipes
special designed paper
fiber optic cleaning
wipes which can
be used for cleaning
laboratory equipment
and instruments,
camera lens, fiber
optic connectors and
other electronic items

31. Tools and Equipment for Fiber
Optics Implementation
Fiber Optics Alcohol
Use to clean fiber optic
cables.

32. Tools and Equipment for Fiber
Optics Implementation
Optical Light Source
a source of light (laser,
LED, etc.) is used to
emit electromagnetic
radiation in order to
perform a specific task,
whether detecting
faults, breaks and
microbends,
characterizing link-loss
or certifying LAN/WANs

33. Tools and Equipment for Fiber
Optics Implementation
visual fault identifier or visual
fault locator (VFI / VFL)
Produces visible red
laser designed to inject
visible light energy into
a fiber. Sharp bends,
breaks, faulty
connectors and
other faults will “leak”
red light allowing
technicians to visually
spot the defects.

34. Tools and Equipment for Fiber
Optics Implementation
Fusion machine
used for the joining of
plastic pipe and
fittings. These tools
can be used to join
polypropylene,
polyethylene, PVDF and
ECTFE pipe. Fusion
machines heat up the
ends of pipes and
fittings, then forces
them together to form
a bond.

35. Tools and Equipment for Fiber
Optics Implementation
Fiber Mechanical
Splicing Device Use in aligning two
fiber optics together
using an alignment
device and index
matching gel that has a
similar refractive index
and covers the possible
air gaps, helping light
travel from one fiber to
another with minimal
loss and little back
reflection

36. Tools and Equipment for Fiber
Optics Implementation
Fiber Connectors