Fiber Attenuation Measurements

Optical Communications

This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “Fiber Attenuation Measurements”.

1. A technique used for determining the total fiber attenuation per unit length is ________ method.
a) Frank
b) Cut-off
c) cut-back
d) Erlangen

2. The system designer finds greatest interest in the ______________
a) Overall fiber attenuation
b) Fiber dispersion
c) Latitude of the fiber
d) Durability

3. How many parameters are usually worked upon by the measurement techniques in attenuation?
a) Three
b) Two
c) One
d) Five

4. What type of light source is usually present in the cut-back method?
a) Tungsten or xenon
b) LED
c) Laser
d) Photo-sensor

5. The device used to remove any scattered optical power from the core is __________
a) Mode setup terminator
b) Nodal spectrum
c) Mode stripper
d) Attenuator

6. What is the hierarchy of the process at the receiving end of the cut-back technique?
a) Photodiode – photo-detector – lock-in amplifier
b) Photodiode – lock-in amplifier
c) Photodiode – photo-detector – Attenuator
d) Photo-detector – lock-in amplifier – receiver

7. What is the unit of measurement of the optical attenuation per unit length?
a) dB-km
b) dB/km
c) km/dB
d) V

8. Determine the attenuation per kilometer for a fiber whose length is 2 km, output voltage is 2.1 V at a wavelength of 0.85μm. The output voltage increases to 10.7 V when the fiber is cut-back to leave 2 metres. Determine the attenuation per km for the fiber at wavelength 0.85μm.
a) 2.8dB/km
b) 3.1dB/km
c) 3.5dB/km
d) 8dB/km

9. ___________ are used to allow measurements at a selection of different wavelengths.
a) Diaphragms
b) Spot attenuators
c) Belts
d) Interference filters

10. Cut-back technique is destructive.
a) True
b) False

11. Which technology is used by the backscatter measurement method?
a) Refraction
b) Francis flat recovery
c) Optical time domain reflectometry
d) Optical frequency

12. ________________ measurements checks the impurity level in the manufacturing process.
a) Material reflectometry
b) Material absorption loss
c) Material attenuation loss
d) Calorimetric loss

13. _____________ may be achieved by replacing the optical fibers with thin resistance wires.
a) Diffraction
b) Segmentation
c) Calorimetric calibration
d) Electrical calibration

14. A scattering cell consists of ______ square solar cells called as Tynes cell.
a) Five
b) Four
c) Six
d) Three

15. ___________ removes the light propagating in the cladding.
a) Cladding mode strippers
b) Core strippers
c) Mode enhancers
d) Attenuators

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