NCTI Exam Fiber II UPDATED ACTUAL
Exam Questions and CORRECT Answers
Why was the zero-dispersion point in single-mode fiber moved to 1,550 nm? - CORRECT
ANSWER - To take advantage of the low intrinsic absorption and lower attenuation at 1,550
nm in single-mode fiber.
What type of single-mode fiber is intended for fiber-to-the-home (FTTH) installations? -
CORRECT ANSWER - The ITU-T G.657 bend-insensitive fiber (BIF).
What are the primary causes of intrinsic loss in single-mode fiber? - CORRECT ANSWER -
Material absorption and Rayleigh scattering.
The phenomenon, total internal reflection, is what enables an optical fiber to guide light. What
characteristic of optical fiber causes total internal reflection? - CORRECT ANSWER - The
difference in refractive indexes, between cladding and core, causes light to be reflected off the
cladding and back into the core along the optical fiber.
Where would you expect Fresnel reflections to occur in a fiber-optic network? - CORRECT
ANSWER - At connections and mechanical splices where the signal source is entering or
exiting the cable.
Chromatic dispersion is a combination of which two dispersions? - CORRECT ANSWER -
Material and waveguide dispersion.
What is one advantage and one disadvantage of single-mode fiber with a large mode field
diameter (MFD)? - CORRECT ANSWER - The larger the MFD, the easier it is to splice and
connectorize the fiber, although it becomes more sensitive to bending losses.
What is the current standardized outside diameter (OD) of the cladding of single-mode fiber? -
CORRECT ANSWER - It is 125 μm, with an accuracy of ±1 μm.
Exam Questions and CORRECT Answers
Why was the zero-dispersion point in single-mode fiber moved to 1,550 nm? - CORRECT
ANSWER - To take advantage of the low intrinsic absorption and lower attenuation at 1,550
nm in single-mode fiber.
What type of single-mode fiber is intended for fiber-to-the-home (FTTH) installations? -
CORRECT ANSWER - The ITU-T G.657 bend-insensitive fiber (BIF).
What are the primary causes of intrinsic loss in single-mode fiber? - CORRECT ANSWER -
Material absorption and Rayleigh scattering.
The phenomenon, total internal reflection, is what enables an optical fiber to guide light. What
characteristic of optical fiber causes total internal reflection? - CORRECT ANSWER - The
difference in refractive indexes, between cladding and core, causes light to be reflected off the
cladding and back into the core along the optical fiber.
Where would you expect Fresnel reflections to occur in a fiber-optic network? - CORRECT
ANSWER - At connections and mechanical splices where the signal source is entering or
exiting the cable.
Chromatic dispersion is a combination of which two dispersions? - CORRECT ANSWER -
Material and waveguide dispersion.
What is one advantage and one disadvantage of single-mode fiber with a large mode field
diameter (MFD)? - CORRECT ANSWER - The larger the MFD, the easier it is to splice and
connectorize the fiber, although it becomes more sensitive to bending losses.
What is the current standardized outside diameter (OD) of the cladding of single-mode fiber? -
CORRECT ANSWER - It is 125 μm, with an accuracy of ±1 μm.
