Optical Communications Mid - I, September - 2014
1.Which of the following wavelengths is one of the Optical Windows?
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800-900 nm
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655nm
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350-500 nm
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All the above
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Answer: A
2.For a give Optical fiber, the refractive index of core is given as 1.5, refractive index of cladding is given as 1.47, Numerical aperture is given by _________
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0.56
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0.3
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0.11
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0.45
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Answer: B
3.For an Optical fiber having a Numerical Aperture of 0.4, the acceptance angle for Meridional rays is given by
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33.60
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45.60
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23.60
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54.60
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Answer: C
4.Loss that occur due to microscopic variations in material density from compositional fluctuations or defects during fiber manufacture are
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Absorption loss
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Scattering loss
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Bending loss
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Core-cladding loss
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Answer: B
5.Chalgenide glass is used in the manufacturing of optical switches and fiber lasers due to
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More Stability
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High Optical Non Linearity
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More resistant to High Temperatures
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All the above
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Answer: B
6.Material Dispersion can be reduced by choosing sources with
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Narrower Spectral output width
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Broader Spectral output width
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Operating with longer wavelength
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Both a and d
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Answer: D
7.Intermodal dispersion in multimode fibers can be minimized with the use of
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Step Index fibers
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Graded Index fibers
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Both a and b
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cannot be minimized
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Answer: B
8.Which of the following Splicing techniques automatically performs lateral, longitudinal and angular alignment
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Fusion Splicing
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V-Groove Splicing
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Elastic tube Splicing
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Both b & C
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Answer: C
9.For optical fiber communication requiring bandwidth greater than 200 MHz, the following optical source is preferred.
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Edge Emitter LED
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Surface Emitter Led
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Semiconductor Injection Laser diode
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Ruby Laser
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Answer: C
10.Which of the following is used to split the broad spectral emission of LED into narrow spectral slices?
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Waveguide grating array
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V- grove Splicing
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Distributed Brass reflector
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None of the above
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Answer: A
11.A Fiber splice is a ______________________ joint between two fibers.
Answer: Permanent or Semi-permanent
12.Laser Consists of an active medium to produce ____________________
Answer: Optical Amplification
13._______________ Dispersion occurs due to variation of refractive index of the core material as a function of wave length.
Answer: Material
14.In case of graded index fiber, for triangular profile V number can be increased by a factor of ______________
Answer: √3
15.An extended temperature range at which glass becomes fluid is called _____________ temperature.
Answer: Melting
16.The angle at which the refracted ray will be parallel to the interface is known as ______________
Answer: Critical angle
17.A fiber having a core of constant refractive index and a cladding of a slightly lower refractive index than core is known as _______________
Answer: Step Index Fiber
18.__________________ is defined as the number of electron hole carrier pairs generated per incident photon of energy hγ.
Answer: Quantum Efficiency
19.Two Popular Butt joint alignment designs are ________________ and _____________
Answer: Straight Sleeve and Tapered Sleeve
20.The fundamental mode that propagates in an optical fiber is _______________
Answer: HE11