## EC6702 OCN 2marks

Anna University Regulation 2013 ECE EC6702 OCN 2marks & 16marks for all 5 units are provided below. EC6702 OCN Short answers, Question Bank for Optical Communication Networks Engineering are listed down for students to make perfect utilization and score maximum marks with our study materials.

### DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

#### Unit-1 Part-A

1. A point sorce of ligth is 12 cm below the surface of a large body of water (n = 1.33). What is the radius of the largest circle on the water surface through whichthe light can emerge?
2. Consider a parabolic index waveguide with n1=1.75 , n2 = 1.677 and core radius 25 micro meter. Calculate the numerical aperture at the axis and at a point 20 micro meter from the axis
3. Define numerical aperture of a step index fiber
4. Define mode-field diameter
5. Commonly available single mode fibers have beat lengths in the range 10 cm < Lp <2 m . What range of refractive index diffrences does this correspond to? (for wavelength = 1300 nm)
6. Define mode field diameter
7. What is the fundamental parameter of a single mode fiber?
8. A step index fiber has a normalized frequency V = 26.6 at 1300 nm wavelength. If the core radius is 25 pm, find the numerical aperture

#### Part-B

9. (i) Discuss the signal distortion in single mode fibers (ii) Discuss pulse broadening in graded index fibers with necessary equations
10. (i)Discuss the propagation modes in single-mode fiber
(ii) Discuss the structure of graded index fiber
11. (i) What is meant by ‘material dispersion’? Derive its expression
12. (a) What are fiber modes? Explain mode theory for optical fibers in detail. Or
(b) Compare Single mode fibers and Graded index fibers. Explain the requirements for fiber materials.

#### Unit-2

13. Write the expression for the effective number of modes guided by a curved multimode fiber of radius ‘a’
14. Define normalized propagation constant
15. Give expression for the effective number of modes guided by a curved multimode fiber
16. What are the causes of absorption
17. Find the coupling loss for two fibers having core refractive index profiles alpha E = 2.0 and alpha R = 1.5 .
18. What causes mode coupling
19. Mention the two causes of intra-modal dispersion.
20. Define fiber loss.
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