Download GTU B.Tech 2020 Winter 6th Sem 2161005 Optical Communication Question Paper

Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Winter 6th Sem 2161005 Optical Communication Previous Question Paper

Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER?VI (NEW) EXAMINATION ? WINTER 2020
Subject Code:2161005 Date:01/02/2021
Subject Name:Optical Communication
Time:02:00 PM TO 04:00 PM Total Marks: 56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.



Q.1 (a) Briefly describe the block diagram of Optical
03
Communication System.

(b) Explain in brief the transmission windows of OC.
04

(c) Describe double crucible Method for fiber fabrication.
07


Q.2 (a) Define the following w.r.to propogation modes in OFC:
03
(i)
Transverse
Propagation
Constant(ii)
V
Number(iii)Group Velocity

(b) Compare Single Mode and Multi Mode fibers.
04

(c) Describe fiber Bending Losses in brief.
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 25m,core refractive index
of 1.48 and cladding refractive index of 1.46. How modes
propagate in this fiber at 1320 nm and 1550nm.

(c) Describe different lensing schemes used in optical cable
07




Q.4 (a) Compare SLED (Surface emitting )and ELED(Edge
03
emitting) as fiber source.

(b) A multimode graded index fiber exhibits total pulse
04
broadening 0.1 sec over a distance of 12 km.
Calculate(i)Optimum bandwidth on the link assuming no
inter symbol interference.(ii) pulse broadening per unit
length.

(c) Explain various losses taking place at fiber to fiber joints.
07



Q.5 (a) Explain in brief dark current noise in photo detector.
03

(b) Describe the structure of P-I-N photo detector in brief.
04

(c) Explain different techniques of splicing in brief.
07



Q.6 (a) Briefly describe temperature effect on Gain of APD.
03

(b) Explain APD in brief.
04

(c) Derive the equation for the power launched from LED
07
source in to a S.I. Fiber.
Q.7 (a) How will you measure intermodal dispersion in frequency
03
domain?

(b) Mention the requirement of good optical switch.
04

(c) Discuss optical power loss model for a point to point link.
07
1

---

Q.8 (a) How will you measure chromatic dispersion?
03
(b) Compare SOA and EDFPA.
04
(c) Briefly explain wavelength converter in optical
07
components .


*************
2

---