Optical Fibre Communication MCQ Unit 1

         Optical Fiber Communication

Note: Answer of questions are in bold options

UNIT-1

 

1.   Multimode step index fiber has

a)  Large core diameter & large numerical aperture

b)  Large core diameter and small numerical aperture

c)   Small core diameter and large numerical aperture

d)  Small core diameter & small numerical aperture

2.   A typically structured glass multimode step index fiber shows as variation of attenuation in range of

a)   1.2 to 90 dB km^-1at wavelength 0.69μm

b)   3.2 to 30 dB km^-1at wavelength 0.59μm

   c)   2.6 to 50 dB km^-1at wavelength 0.85μm

d)   1.6 to 60 dB km^-1at wavelength 0.90μm

3.   A multimode step index fiber has a large core diameter of range

a)  100 to 300 μm

b)  100 to 300 nm

c)  200 to 500 μm

d)  200 to 500 nm

 

4.   Multimode graded index fibers are manufactured from materials with

a)  Lower purity

b)  Higher purity than multimode step index fibers.

c)  No impurity

d)  Impurity as same as multimode step index fibers.

 

5.   The performance characteristics of multimode graded index fibers are

a)  Better than multimode step index fibers.

b)  Same as multimode step index fibers.

c)   Lesser than multimode step index fibers

d)  Negligible

 

6.   The fibers mostly not used nowadays for optical fiber communication system are

a)  Single mode fibers

b)  Multimode step fibers

c)   Coaxial cables

d)  Multimode graded index fibers

 

7.   Which law gives the relationship between refractive index of the dielectric?

a)  Law of reflection

b)  Law of refraction (Snell’s Law).

c)  Millman’s Law

d)  Huygen’s Law

 

8.   The light sources used in fibre optics communication are:

a)  LED’s and Lasers

b)  Phototransistors

c)  Xenon lights

d)  Incandescent

 

9.   What is the numerical aperture of the fiber if the angle of acceptance is 16 degree a) 0.50

b) 0.36

c) 0.20

d) 0.27

 

10.   Which equations are best suited for the study of electromagnetic wave propagation?

a)  Maxwell’s equations

b)  Allen-Cahn equations

c)  Avrami equations

d)  Boltzmann’s equations

 

11.   A monochromatic wave propagates along a waveguide in z direction. These points of constant phase travel in constant phase travel at a phase velocity V_p is given by

a)  V_p=ω/β

b)  V_p=ω/c

c)   V_p=C/N

d)  V_p=mass/acceleration.

12.   The phenomenon which occurs when an incident wave strikes an interface at an angle greater than the critical angle with respect to the normal to the surface is called as

a)  Refraction

b)  Partial internal reflection

   c)  Total internal reflection

d)  Limiting case of refraction

 

13.     How many propagation modes are present in single mode fibers?

a)   One

b)  Two

c)   Three

d)   Five

 

14.   Meridional rays in graded index fibers follow

a)   Straight path along the axis

b)  Curved path along the axis

c)   Path where rays changes angles at core-cladding interface

d)   Helical path

 

15.   A graded-index fiber has a core with parabolic refractive index profile of diameter of 30μm, NA=0.2, λ=1μm. Estimate the normalized frequency.

a) 19.32

b) 18.84

c) 16.28

d) 17.12