Non – Semiconductor Lasers

Optical Communications

This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “Non – Semiconductor Lasers”.

1. ____________________ lasers are presently the major laser source for optical fiber communications.
a) Semiconductor
b) Non-Semiconductor
c) Injection
d) Solid-state

2. In Nd: YAG lasers, the maximum doping levels of neodymium is ____________
a) 0.5 %
b) 1.5 %
c) 1.8 %
d) 2 %

3. Which of the following is not a property of Nd: YAG laser that enables its use as an optical fiber communication source?
a) Single mode operation
b) Narrow line-width
c) Long lifetime
d) Semiconductors and integrated circuits

4. The Nd: YAG laser has a narrow line-width which is ________________
a) < 0.01 nm
b) > 0.01 nm
c) > 1 mm
d) > 1.6 mm

5. The strongest pumping bands is a four level system of Nd: YAG laser at wavelength of range_________________
a) 0.25 and 0.56 nm
b) 0.75 and 0.81 nm
c) 0.12 and 0.23 nm
d) 1 and 2 nm

6. The Nd: YAG laser is costlier than earth-doped glass fiber laser.
a) True
b) False

7. It is a resonant cavity formed by two parallel reflecting mirrors separated by a mirror separated by a medium such as air or gas is?
a) Optical cavity
b) Wheatstone’s bridge
c) Oscillator
d) Fabry-perot resonator

8. In a three level system, the threshold power decreases inversely with the length of the fiber gain medium.
a) True
b) False

9. Which of the following co-dopant is not employed by neodymium and erbium doped silica fiber lasers?
a) Phosphorus pent oxide
b) Germania
c) Nitrogen
d) Alumina

10. Dopants levels in glass fiber lasers are generally ___________
a) Low
b) High
c) Same as that of GRIN rod lens laser
d) Same as that of semiconductor laser

11. _______________ fibers include addition of lead fluoride to the core glass in order to raise the relative refractive index.
a) Solid-state
b) GaAs
c) Semiconductor

12. The lasing output of the basic Fabry-perot cavity fiber is restricted to between ____________
a) 1 and 2 nm
b) 5 and 10 nm
c) 3 and 6 nm
d) 15 and 30 nm

13. In Fabry-perot laser, the lower threshold is obtained by ___________
a) Increasing the refractive index
b) Decreasing the refractive index
c) Reducing the slope efficiency
d) Increasing the slope efficiency

14. When did the non-semiconductor laser developed?
a) 1892
b) 1946
c) 1985
d) 1993

15. Y3Al5 O12 is a molecular formula for _____________
a) Ytterbium aluminate
b) Yttrium oxide
c) Ytterbium oxy-aluminate
d) Yttrium-aluminum garnet

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