Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Summer 6th Sem 2161005 Optical Communication Previous Question Paper
Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER? VI EXAMINATION ? SUMMER 2020
Subject Code: 2161005 Date:28/10/2020
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 (a) Mention the advantages of Optical Communication
03
System.
(b) Mention the importance and significance of Optical
04
Windows used for optical communication Purpose.
(c) Describe Any one Method for fiber fabrication.
07
Q.2 (a) Define the following w.r.to Optical source and Detectors
03
(i) Response Time(ii) Quantum Efficiency(iii)Sensitivity
(b) Compare S.I. and G.I. fibers.
04
(c) Describe fiber scattering Losses in brief.
07
OR
(c) Discuss intermodal dispersion in optical fibers.
07
Q.3 (a) Compare LED and LASER as fiber optic source.
03
(b) Determine the normalized frequency at 850 nm for a step
04
index fiber has a core radius of 20m,core refractive
index of 1.46 and cladding refractive index of 1.43. How
modes propagate in this fiber at 1320 nm and 1550nm.
(c) Describe different lensing schemes used in optical cable
07
OR
Q.3 (a) Briefly Explain working of ELED(Edge emitting) as
03
fiber sourc and its Major advantage over SLED.
(b) A multimode graded index fiber exhibits total pulse
04
broadening 0.1 sec over a distance of 10 km.
Calculate(i)Optimum bandwidth on the link assuming no
inter symbol interference.(ii) pulse broadening per unit
length.
(c) Derive the formula to compute loss for axial mis
07
alignment taking place at fiber to fiber joints.
Q.4 (a) Explain in brief dark current noise in photo detector.
03
(b) Describe the structure of APD (Avalanche photo detector
04
)in brief.
(c) Explain different techniques of splicing in brief.
07
OR
Q.4 (a) Briefly describe temperature effect on Gain of APD.
03
(b) Explain PIN as photo detector in brief.
04
(c) Derive the equation for the power launched from LED
07
source in to a G.I. Fiber.
1
Q.5 (a) How will you measure intermodal dispersion in
03
frequency domain?
(b) Mention the requirement of good optical switch.
04
(c) Discuss optical power loss model for a point to point
07
link.
OR
Q.5 (a) How will you measure chromatic dispersion?
03
(b) Compare SOA and EDFPA.
04
(c) Briefly explain Couplers in optical components.
07
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This post was last modified on 04 March 2021