This document discusses different types of optical fibers based on their material composition, propagation mode, and refractive index profile. There are three main types of materials used: plastic core with plastic cladding, glass core with plastic cladding, and glass core with glass cladding. Fibers can propagate light in single mode or multimode. The refractive index can have a step profile or graded profile.

1. Optical fibres
S.P.B.Patel engineering college
Linch,Mehsana
Project by:-
Patel Sujay A
Patel Pratik C
Patel Mithilesh
Patel Princ
Patel Saumil

2. Type of Optical fibres
1> MATERIALS OF WHICH THE
FIBRES ARE MADE.
1) Plastic core with Plastic
cladding.
2) Glass core with Plastic
cladding.[pcs]
3) Glass core with Glass
cladding.[scs]
2>THE MODE OF
PROPAGATION
1> singlemode fiber.
2> multimode fibre.
3>THE REFRACTIVE
INDEX(INDEX PROFILE).
1)step-index fibre
2)Gradedindex fibre

3. Type of fibres
1> MATERIALS OF WHICH THE FIBRES ARE MADE.
2>THE MODE OF PROPAGATION.
3>THE REFRACTIVE INDEX(INDEX PROFILE).

4. Types of optical fbires based on material
1) Plastic core with Plastic cladding.
2) Glass core with Plastic cladding.[pcs]
3) Glass core with Glass cladding.[scs]

5. Plastic core with plastic cladding
This type of fibres are commonly used because, in this both the core and the cladding
being made up of same material simplifies the production process.

6. Glass core with plastic cladding
 Fibres with glasscore exhibit low attenuation characteristics. The PCS fibers
are less affected by radiation and hence more sutible for military application.

7. Glass core with glass cladding
 The attenuation characteristics of this SCS fibre are slightly better than PCS.
These fibres havebest propagation characteristics and can also be easily
terminated. SCS fibres are least rugged and they are more susceptible yo
increase in attenuation in radiation areas.

8. Propagation of light through an optical fibre
Mode of propagation
1> singlemode fiber.
2> multimode fibre.

9. Singlemode fibre
Singlemode fibres are capable of wide bandwidths and are ideally
suited for long haul communication. Low cost and high capacity
circuites for the transmission of telephone and television etc.,are
the additional features of this fibre.

10. Multimode fibres
Fibres withcores of about 20 to 100mm diameter, support many waveguide
modes.these fibres and ideally suited for high bandwidth medium haul
application.the upper limit of the mode is determined by the core dia
meter and numerical aperture.

11. Index pofile fibres
1)step-index fibre
2)Gradedindex fibre

12. Step-index fibre
Step index fibre has a central core with a uniform refractive index.the core
surrounded by an outside cladding with a uniform refractive index less than
that of the central core.in figure shows the index profile for a step-index
fibre. Form the fig. it is seen that, there is an abrupt change in the
refractivIndex at the core/cladding interface and hence the refractive index
profile takes the shape of a step. Hence, the name step-index fibre.

13. Graded index fiber(GRIN fibre)
In grin fibre the refractive index of the core is
non-uniform,it is highest at the center and
decreases gradually with distance toword the
outer edge.