Optical Communication & Networks - Dec 2015

Electronics & Telecomm. (Semester 7)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Differentiate DWDM, WDM and SONET.(5 marks) 1 (b) What is optical safety?(5 marks) 1 (c) Differentiate LED and LASER sources.(5 marks) 1 (d) Compare different types of splicing techniques.(5 marks) 2 (a) Draw the block diagram of optical communication and state its advantages and disadvantages.(10 marks) 2 (b) Explain different types of fibres with their refractive index profile and mention its dimensions.(5 marks) 2 (c) A multimode GIF exhibits total pulse broadening of ms over a distance of 15 km.
Estimate:
i) The maximum possible Bandwidth on the link assuming no ISI.
ii) The pulse dispersion per unit length.
iii) The Bandwidth length product.(5 marks) 3 (a) What is macro-bending loss. Explain with neat diagram. Explain how to minimize micro-bending losses.(10 marks) 3 (b) Explain OTDR with a neat sketch and mention its advantages and applications.(5 marks) 3 (c) Derive an Expression for responsivity of PIN photodiode.(5 marks) 4 (a) What are optical amplifiers. Explain different types of front end amplifiers.(7 marks) 4 (b) Explain in detail working principle of RAPD. Why it is called reach through APD and compare its working with PIN diode.(8 marks) 4 (c) Explain SONET architecture in detail.(5 marks) 5 (a) Explain working principle of isolator with neat sketch. Also compare isolator and circulator.(10 marks) 5 (b) Write a short note on link power budget.(10 marks) 6 (a) Explain OTDM in detail.(10 marks) 6 (b) Explain optical access networks.(10 marks)