Fibre optics is a technology that we should know its properties as a science student.

1. Fibre optics
Fibre optics it is branch of physics which deals with the transmission
and reception of light waves using optical fibres, which acts a guiding
media.

2. Principle:
 The principle of optical fiber communication is TOTAL INTERNAL REFLECTION.
 Conditions:
 Light should travel from denser to rarer medium.(n1>n2)
 The angle of incidence should be greater than the critical angle. (ф > фc)

3. Construction:
 It is made up of transparent dielectrics (sio2) ,(glass or plastics).
 Central core glass (50 μm) diameter and it is surrounded be a cladding (125-
200μm).
 Lower refractive index than core .
 Materials :
 Glass fibre:
 core – siO2 ; GeO2-siO2.
 Cladding – p2O3 – sio2 ; sio2.
 Plastic fibre:
 Core – polymethyl methacrylate ; polystyrene.
 Cladding – co-polymer; methacrylate.

4. Glass and plastic fibers:

5. Mode:
 Mode is the one which describe the nature of propagation of
electromagnetic waves in a wave guide.
 m

6. Step index and Graded index:
Veriation of refractive index in core.

7. Losses in optical fibres:
 Attenuation loss: loss of optical signals.(lowering of signal strength)
 Radiative loss: micro bend & macro bend.

8. Optical fibre in world wide:

9. Optical fibre size comparsion:

10. Fiber connections:

11. Government of India:
 Department of Telecom’s Digital Communication Commission sanctioning
₹1,815 crore to Tamil Nadu under the BharatNet scheme, the State
government is planning to lay 55,000 km of optical fibre cable across the
State and provide internet facility at speeds of up to 1Gbps.
 Chief Minister Edappadi K. Palaniswami aims to connect all the Corporations,
Municipalities and Town Panchayats through optic fibre cable. “We will be
laying about 55,000 km of optical fibre cable across the State and connect
12,524 village panchayats


12. Field used:
 Internet
 Fiber optic cables transmit large amounts of data at very high speeds.
 Cable Television
 These cables are ideal for transmitting signals for high definition
 Telephone
 Calling telephones within or outside the country has never been so easy.
 Surgery and Dentistry
 Optical communication is an important part of non-intrusive surgical methods, popularly known as
endoscopy.
 Mechanical Inspections
 Fiber optic cables are widely used in the inspection of hard-to-reach places.
 Military and Space Applications
 With the high level of data security required in military and aerospace applications.
 Automotive Industry
 used in lighting, both in the interior and exterior of vehicles.


13. *

14. DEPARTMENT OF
PHYSICS
By G.Shenbaga Rajan
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