Quiz  /  Optical communication Gate & PSU MCQ Questions With Answers

  • 1. 
    Optical fibers suffer radiation losses at bends or curves on their paths. State true or false.

  • True
  • False

  • 2. 
    Range of optical communication

  • 700 nm to 1700 nm
  • 800 nm to 1700 nm
  • 800 nm to 1200 nm
  • 800mm to 1600 mm

  • 3. 
    Which communication gives larger repeater spacing ?

  • Coaxial cable
  • Twisted pair cable
  • Microwave communication system

  • 4. 
    Helium-Neon LASER is a:

  • Gas LASER
  • Liquid LASER
  • Solid LASER
  • Plasma Laser

  • 5. 
    What are fibre optics?

  • thin, flexible fibres of glass/plastic
  • flexible fibers of copper
  • strands of rubber
  • those glow toys

  • 6. 
    Optical fibers work on the principle of

  • total internal refraction
  • total internal absorption
  • total internal reflection
  • total internal flow

  • 7. 
    A multimode fiber has RMS pulse broadening per km of 12ns/km and 28ns/km due to material dispersion and intermodal dispersion resp. Find the total RMS pulse broadening.

  • 30.46ns/km
  • 31.23ns/km
  • 28.12ns/km
  • 26.10ns/km

  • 8. 
    What is OTDR

  • Optical Time Domain Reflectometer
  • Optical Transient Difference Recorder
  • Open Transform Direct Receiver

  • 9. 
    Determine the total carrier recombination lifetime of a double heterojunction LED where the radioactive and nonradioactive recombination lifetime of minority carriers in active region are 70 ns and 100 ns respectively.

  • 41.17 ns
  • 35 ns
  • 40 ns
  • 37.5 ns

  • 10. 
    Consider a single mode fiber having core refractive index n1= 1.5. The fiber length is 12m. Find the time taken by the axial ray to travel along the fiber

  • 1.00μsec
  • 0.06μsec
  • 0.90μsec
  • 0.30μsec

  • 11. 
    A silicon p-i-n photodiode incorporated in an optical receiver has following parameters:Quantum efficiency = 70%Wavelength = 0.8 μmDark current = 3nALoad resistance = 4 kΩIncident optical power = 150nW.Bandwidth = 5 MHzCompute the photocurrent in the device.

  • 67.7nA
  • 81.2nA
  • 68.35nA
  • 46.1nA

  • 12. 
    The beat length in a single mode optical fiber is 8 cm when light from a laser with a peak wavelength 0.6μm is launched into it. Estimate the modal birefringence.

  • 1×10-5
  • 3.5×10-5
  • 2×10-5
  • 4×10-5

  • 13. 
    Intermodal dispersion is nonexistent in ________ fibers.

  • a) Multimode
  • b) Single mode
  • c) Step index- multimode
  • d) Al-GU

  • 14. 
    Which of the following is/are the condition(s) for total internal reflection to take place?

  • I only
  • II only
  • I and II only
  • II and III only

  • 15. 
    What are the three optical windows in fiber optics communication?

  • 750nm, 1350nm, 1600 nm
  • 850nm, 1300nm, 1550nm
  • 800, 1100, 1600
  • 850nm, 1300nm, 1450nm
  • 850mm, 1300mm, 1550nn

  • 16. 
    The scattering resulting from fiber imperfections like core-cladding RI differences, diameter fluctuations, strains, and bubbles is?

  • Rayleigh scattering
  • Mie scattering
  • Stimulated Brillouin scattering
  • Stimulated Raman scattering

  • 17. 
    An optical fiber has core-index of 1.480 and a cladding index of 1.478. What should be the core size for single mode operation at 1310nm?

  • 7.31μm
  • 8.71μm
  • 5.26μm
  • 6.50μm

  • 18. 
    ____________ is a multi-functional element of optical network.

  • Hop
  • Optical node
  • Wavelength
  • Optical attenuation

  • 19. 
    Which kind of dispersion phenomenon gives rise to pulse spreading in single mode fibers?

  • Intramodal
  • Intermodal
  • Material
  • Group Velocity

  • 20. 
    The significance of fourth generation optical communication system is

  • Optical amplifier
  • Optical source
  • Optical coupler
  • splicers

  • 21. 
    _________ reconstitutes a transmitted digital optical signal.

  • a) Repeaters
  • b) Optical amplifiers
  • c) Modulators
  • d) Circulators
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