Master of Science II (Electronics-Communication Science)
Examination: Oct Nov 2016 Semester IV (New CGPA)
SLR No. Day
Date Time Subject Name Paper
No. Seat No.
SLR SJ
361
Tuesday
22/11/2016
02.30 PM
To
05.00 PM
Fiber Optic
Communication
C
XV
Instructions: Q. no. 1 and Q. no 2 are compulsory
Attempt any three questions from Q. No.3 to Q. No. 7
All questions carry equal marks.
Use of scientific calculator is allowed.
Total Marks: 70
Q.1 Select correct alternative 06
The laser source provides the signal that is.
Coherent in light source Possible to modulate at frequency
Low divergence beam All the above
The first step for preparation of fiber is.
Ultra pure material powder Conventional glass refining technique
Impure fiber preparation All the above
The optical carrier frequency is in the range of
1013 to 1016 Hz 1014 to 1016 Hz
1013 to 1017 Hz 1011 to 1016 Hz
Intermodal Dispersion occur in
Single mode fiber Multimode fiber
Single mode graded index fiber None of these
Microscopic meandering of the fiber core axis, known as
Microbending Linear Bending
Non linear bending Circular bending
In optical fibers the Cut-Back technique is used to measured
Spectral loss Dispersion loss
Absorption loss None of these
State True of False of below statements 08
Material absorption is a loss mechanism related to the material composition
and the fabrication process for the fiber.
Meridional ray which passes through the cross section of fiber.
Photon energy is inversely proportional to wavelength.
Insertion loss is to measure the diameter of optical fiber
A permanent joint formed between two individual optical fibers in the field or
factory is known as a Fiber splice.
The typical best bandwidth length product for single mode step index fiber is
100MHZ KM
The most common on-line measurement techniques uses fiber image
projection (shadow method) for the measurement of outer diameter of fiber.
SBS (stimulated Brillouin scattering) is mainly a backward process.
Page 1 of 2
Q.2 Write short notes
Explain fiber alignment and joint loss?
Explain the principle of PIN photodiode?
Explain briefly cut-off wavelength measurement method?
05
05
04
Q.3 Using the simple ray theory of light, describe the mechanism for the transmission
of light within an optical fiber?
An optical fiber has a numerical aperture of 0.20 and a cladding refractive index
of 1.59 determine the acceptance angle for the fiber in water has a refractive
index of 1.33.
08
06
Q.4 Briefly writes about step index and graded index fiber?
Explain the requirement of optical cable design
08
06
Q.5 Explain the concept of double heterojunction LED with neat sketch?
A P-N photodiode has a quantum efficiency of 60% at a wavelength of
calculate
1. Its responsitivity at
2. Received optical power if mean photocurrent is 10-6 A.
08
06
Q.6 The radiative and nonradiative recombination lifetime of the minority carries in
the active region of a double heterojunction LED are 60ns and 100 ns
respectively. Determine the total carrier recombination lifetime and power
internally generated within the device when peak emission wavelength is 0.87 at
a drive current of 40mA
Explain the different advantages and disadvantages of LED as compare to laser?
08
06
Q.7 Briefly explain how Numerical Aperture is measured in optical fiber?
Write a short note on receiver noise?
08
06