1
Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
PDDC SEMESTER-V EXAMINATION WINTER 2018
Subject Code:X51102 Date: 16/11/2018
Subject Name: Optical Communication
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1

Draw and explain different elements of an optical fiber transmission link
with the functional description of each block.
07

Define the following:
(1)Light
(2)Refractive index
(3)Snell's Law
(4)Critical Angle
(5)Acceptance Angle
(6)Numerical Aperture
(7)Mode
07
Q.2

Explain any one technique for the fabrication of optical fiber in brief.
07

Compare Ray theory and Electromagnetic mode theory for light propagation through fiber.
07
OR

Differentiate between Step Index and Graded Index Fiber.
07
Q.3

State the types of Light Emitting Diodes used in optical system and explain any
one of them with required figure.
07

Write the principle, characteristics and operation of Avalanche photodiode.
07
OR
Q.3

Discuss briefly the distributed-feedback(DFB) laser diode with neat sketch.
07

Draw a summary chart showing different signal degradations in optical fibers.
07
Q.4

State the differences between LEDs and LASERs.
07

Explain Fusion splicing, V-grove splicing.
07
OR
Q.4

What are Eye diagrams? Explain different eye pattern features with diagrams.
07

Discuss optical power loss model for a point to point link.
07
Q.5

Write a brief note on Optical Couplers.
07

Write short notes on Synchronous Optical Fiber Networks(SONET).
07
OR
Q.5

Explain Semiconductor Optical Amplifiers (SOAS).
07

Explain Optical Time Domain Reflectometry (OTDR) method with its benefits over other techniques.
07