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Physics (Second Semester) > Optical Fibres > Flashcards

Flashcards in Optical Fibres Deck (111)
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1

What is the shape of an optical fiber ?

Cylindrical

2

How many parts does it basically consist of ?

Two

3

What are they ?

Core and Cladding

4

Where is the core ?

It is the inner cylindrical part

5

What is the core generally made up of ?

Glass or plastic

6

What is the cladding ?

It is a concentric cylinder, surrounding the core

7

Which material has a higher refractive index ?

Core has a higher refractive index

8

What is used to prepare a jacket for the cladding ?

A polyurethane jacket

9

Why is it protected with a polyurethane jacket ?

It safeguards the fiber from chemical reaction,
And Crushing

10

What physical principle are optical fibers built on ?

Total internal reflection

11

Why is total internal reflection a special case of reflection ?

The ENTIRE incident energy is reflected back. There is ZERO absorption of light energy

12

Would fiber optics communication be possible if there was a very minute loss ?

No, it would be impossible

13

What is a waveguide ?

A tubular structure, which guides energy in the form of waves

14

Which property of light is generally used for analyzing signal propogation in fibers ?

Wave property

15

What is fractional index change ?

It is the ratio of the refractive index difference of the core and cladding to the refractive index of the core

16

Do all the light rays that enter the core at an angle less than the angle of acceptance travel in the core, theoretically ?

No. Maxwell's laws tells us that only light waves of certain number of modes are sustained

17

Which parameter determines the number of modes supported for propagation ?

V - number

18

What is refractive index profile ?

The curve which represents the variation of refractive index with respect to the radial distance from the fiber axis

19

What are the three categories optical fibers are classified into ?

Single mode fiber
Step index multi mode fiber
Graded index multi mode fiber

20

What is a mode ?

Modes are the possible solutions of Helmholtz equations, combined with Maxwell's equations and the boundary conditions

21

What does a mode tell us about a wave ?

How a wave is distributed throughout space

22

Can two waves have the same mode ?

Yes, but with different frequencies

23

What is the diameter of the core in single mode optical fiber ?

8-10 micro meter

24

Which is the most commonly used optical fiber in the world ?

Single Mode Optical Fiber

25

Where do Single mode Optical Fibers find application, particularly ?

Submarine cable system

26

What is splicing ?

Joining the strands of one optical fiber to another

27

Can it be done with twisting and soldering ?

No

28

How is it done ?

The ends of respective strands are fused using mechanical splices

29

What is the special property of the core of Graded-Index Multimode Fiber ?

The refractive index decreases radially outward

30

Which is the most expensive type of optical fiber ?

Graded Index Multimode Fiber (GRIN) is the most expensive optical fiber