Fibre optic cable definition and related terms,propagation modes,performance characteristics,composition of cable,fibre optic sizes,applications,advantages and disadvantages in simple form

1. OPTICAL FIBRE CABLE
prepared by,
Hasmath Naseera.A

2. DEFINITION:
 An optical fiber cable is a CABLE
containing one or more optical fibers that
are used to carry light.
 It is made of glass or plastic and transmits
signals in the form of light.

3. CHARACTERISTICS
 Light travels in a straight line as long
as it is moving through a single
uniform substance.
 If a ray of light travelling through one
substance & suddenly enters another
substance, the ray changes direction.

4. REFRACTION:
 If a ray of light travelling through one
substance suddenly enters
another(more or less dense)
substance, its speed changes
abruptly, causing the ray to change
direction.
 This change is called Refraction

5. CRITICAL ANGLE:
 A beam of light moving from a more
dense medium to less dense medium.
 At some point, the change in the
incident angle results in a refracted
angle of 90 degrees. The incident
angle at this point is known as
CRITICAL ANGLE.

6. Representation:

7. REFLECTION:
 When the angle of incidence becomes
greater than the critical angle a new
phenomenon occurs called
REFLECTION.
 Light no longer passes into the less
dense medium at all.
 Angle of incidence = Angle of
reflection

8. PROPAGATION MODES

9. MULTIMODE
 Multimode is so named because
multiple beams from a light source
move through the core in different
paths.
 The beams within the cable depends
on the structure of core.

10. MULTIMODE STEP INDEX
FIBER
 In multimode step index fiber, the
density of the core remains constant
from the centre to the edges.
 A beam of light moves through its
constant density in a straight line until
it reaches the interface of the core and
the cladding.

11. Multimode step index(coned)..
 At the interface there is abrupt change
to a lower density that alters the angle
of the beam’s motion.
 The term STEP-INDEX refers to
sudden change.

12. MULTIMODE GRADED-INDEX
FIBER
 The multimode graded index fiber,
decreases the distortion of signal
through the cable.
 The word index refers to the index of
refraction.

13. DENSITY OF INDEX FIBER
 Index of refraction refers to density. A
graded index fiber is one with varying
densities.
 Density is highest at the centre of the
core and decreases gradually to its
lowest at the edge

14. SINGLE MODE:
 It uses step index fiber and a highly
focused source of light that limits
beams to a small range of angles.
 It is manufactured with with a much
smaller diameter than that of
multimode fibers,and with substantially
lower density(index of refraction).

16. FIBER SIZES
 Optical fibres are defined by the ratio
of diameter of their core to the
diameter of their cladding, both
expressed in terms of micrometers.
 TYPE:50/125
 CORE:50.0um
 CLADDING:125um
 MODE:multimode,graded index

17. FIBER SIZES:
TYPE CORE(um) CLADDING(u
m)
MODE
50/125 50.0 125 Multimode,gr
aded index
62.5/125 62.5 125 Multimode,gr
aded index
100/125 100.0 125 Multimode,gr
aded index
7/125 7.0 125 Single mode

18. CABLE COMPOSITION
cladding
Core
Optical
fiber
Outer
jacket

19. CABLE COMPOSITION:
 The outer jacket is made of either
PVC or teflon.
 Inside the jacket are Kevlar strands to
strengthen the cable.
 Kevlar is a strong material used in
fabrication of bulletproof vests.
 Below the kevlar is another plastic
coating to cushion the fiber.
 The fiber is at the centre of the cable,
and it consists of cladding and core.

20. Cable composition:

21. Operation:

22. FIBER OPTIC
CONNECTORS

23. FIBRE OPTIC
CONNECTORS:
 The subscriber channel(SC) is used
for cable TV.It uses a push/pull locking
system.
 The straight-tip (ST) connector is used
for connecting cable to networking
devices.
 It uses a bayonet locking s/m and it is
more reliable than SC.
 Eg:MT-RJ

24. Connector:

25. PERFORMANCE:
 Attenuation is flatter than in case of
twisted- pair cable and co-axial cable.
 The performance is such that we need
fewer repeaters while using fiber optic
cable.

26. Performance characteristics:

27. APPLICATIONS:
 Fiber optic cable is backbone of
networks because of its wide
bandwidth and it is cost -
effective.eg:SONET network
 Using Wavelength Division
Multiplexing (WDM),we can transfer
data at a rate of 1600Gbps.
 Cable TV companies
 LAN networks such as 100Base-FX
network &1000Base-X.

28. ADVANTAGES:
 Higher Bandwidth
 Less signal attenuation
 Immunity to electromagnetic
interference
 Resistance to corrosive materials
 Light Weight
 Greater immunity to tapping

29. DISADVANTAGES:
 Cost
 Installation/maintainance
 Fragility
 Unidirectional light propagation

30. THANK YOU…