Download PTU (Punjab Technical University) B.Tech (Bachelor of Technology) / BE (Bachelor of Engineering) 2021 January EE 7th Sem 71971 Optical Fiber Communication Previous Question Paper
Total No. of Pages : 02
Total No. of Questions : 18
B.Tech. (Electrical & Electronics) (2013 & Onwards E-III)/
(Electronics & Electrical) (Sem.?7)
OPTICAL FIBER COMMUNICATION
Subject Code : BTEEE-805C
M.Code : 71971
Time : 3 Hrs. Max. Marks : 60
INST RUCT ION TO CANDIDAT ES :
1 .
SECT ION-A is COMPULSORY cons is ting of TEN questions carrying TWO marks
each.
2 .
SECT ION-B c ontains F IVE questions c arrying FIVE marks eac h and s tud ents
have to atte mpt any FOUR q ues tions.
3 .
SECT ION-C contains THREE questions carrying T EN marks e ach and s tudents
have to atte mpt any T WO questio ns.
SECTION-A
Answer briefly :
1.
Why do we prefer optical fibre communication for long distance communication?
2.
What is the use of splicing?
3.
Which dispersion mechanism (material or waveguide) is a function of the size of the fibre's
core relative to the wavelength of operation?
4.
Differentiate absorption and emission rate.
5.
What are the two analyses usually carried out to ensure the desired performance of optical
fiber transmission link?
6.
In a 50ns pulse 6 ? 106 photons at a wavelength of 1200nm fall on an InGaAs
photodetector. On average 4.2 ? 106 EHPs are generated. Calculate the quantum efficiency
of photodetector.
7.
Draw the layer diagram of a pin photodiode.
8.
Differentiate conventional and dispersion shifted fibers.
9.
What are the benefits of optical multiplexing?
10. What is light wave system?
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SECTION-B
11. Explain the different modulation format applicable to optical communication system.
12. Discuss single mode and multimode fiber with suitable diagram.
13. Draw the structure of the LED. Calculate efficiency of a LED drawing 80 mA of current
when 1.5 V is applied to its terminals and produces 1.5mW of optical power.
14. Explain the construction and working of coupled cavity semiconductor laser.
15. Define the term modal noise and briefly explain the impact of modal noise on fibre
communication.
SECTION-C
16. Define Snell law. Discuss the total internal reflection. Draw a diagram indicating how the
light propagation is effected by numerical aperture.
17. With the help of suitable diagram explain the working of VCSEL.
18. Write a short notes on :
a. Fibre losses.
b. Source fiber coupling.
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 26 June 2021