Optical Communication - Dec 2014

Electronics and Comm. Engg. (Semester 6)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Explain the elements of an optical fiber transmission link with the functional description of each block.(7 marks) 1 (b) Mention the advantages and applications of optical fiber communications.(7 marks) 2 (a) Compare step index fibers and graded index fibers.(7 marks) 2 (b) Compare Ray theory and Electromagnetic mode theory for light propagation through fiber.(7 marks) 2 (c) Explain the fiber fabrication technique along with the schematic of a fiber drawing apparatus.(7 marks) 3 (a) Explain the principle, characteristics and operation of avalanche photodiode.(7 marks) 3 (b) List the types of Light Emitting Diodes used in optical system and explain any one of them with required figure.(7 marks) 3 (c) Discuss the various dispersion mechanisms that contribute to pulse broadening during the fiber transmission.(7 marks) 3 (d) Discuss briefly the distributed-feedback(DFB) laser diode with neat sketch.(7 marks) 4 (a) Write the differences between LEDs and LASERs.(7 marks) 4 (b) Discuss optical power loss model for a point to point link.(7 marks) 4 (c) What are Eye diagrams? Explain different eye pattern features with diagrams.(7 marks) 4 (d) Explain (1) fusion splicing, (2) V-grove splicing.(7 marks) 5 (a) Explain Semiconductor optical Amplifiers (SOAS).(7 marks) 5 (b) Write short notes on Synchronous Optical Fiber Networks(SONET).(7 marks) 5 (c) Explain Optical Time Domain Reflectometry (OTDR) method with its benefits over other techniques.(7 marks) 5 (d) Write a brief note on Optical Couplers.(7 marks)