C G192048 Pages:2

Reg No.:_. Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(R&S), DECEMBER 2019

Course Code: EC405
Course Name: OPTICAL COMMUNICATION
Max. Marks: 100 Duration: 3 Hours
PARTA
Answer any two full questions, each carries 15 marks. Marks
1 a) Explain the mode theory for propagation of light in optical fiber? (9)

b) Draw and explain the Outside vapour-phase deposition process in fiber fabrication? (6)
2 a) Write the working principle of LASER and compare it with LED using neat (9)

diagrams.

0) A graded index fiber with parabolic refractive index has nj=1.48 and no=1.46 if (6)
core radius is 20um.Find the number of modes at 1300nm and 1550nm?
3 ४) Explain different types of intramodal dispersion and derive the expression for (8)

pulse spread and dispersion factor for each case.

b) Explain different types of bending losses in optical fibers? (4)
c) What is meant by Surface emitting LEDs? (3)
PART B
Answer any two full questions, each carries 15 marks.
4 a) Derive an expression for receiver sensitivity and also explain quantum limit . (8)
b) Explain the physical principles of PIN photodetector? (7)

5 ഒ) Discuss the rise-time budget analysis in an optical fiber link and write about its (9)
advantages.

b) 0.5uw of optical power produces a multiplied photocurrent of 10 பூக்‌. Find the
multiplication factor M?

6 ൭ Briefly discuss the fundamental receiver operation in optical communication. (6)

b) Write the advantages of Soliton based communication and explain the generation of (5)

soliton wave.

Page lof 2