NCTI EXAM FIBER II EXAM | QUESTIONS AND ANSWERS |
VERIFIED AND WELL DETAILED ANSWERS | LATEST EXAM
UPDATE
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.
What do diameter differences between spliced fibers look like on an optical
time domain reflectometer (OTDR)? - CORRECT ANSWER - Gain in one
direction and high loss in the opposite direction.
Besides protection, what else must the coating on an optical fiber do? -
CORRECT ANSWER - Function over a wide temperature range; be
compatible with cable gels; adhere to the glass cladding over the lifetime of the
cable; and be mechanically strippable for splicing operations.
How do technicians know the specific type of single-mode fiber used in a
particular project? - CORRECT ANSWER - They have read the project's
specification records.
Which type of fiber-optic cable provides the most stable transport
characteristics and additional protection from stresses caused by macrobends
and microbends? - CORRECT ANSWER - Loose-tube cable.
What is a consideration for the use of ribbon fiber? - CORRECT ANSWER -
Ribbon fiber requires different tools and equipment to perform splicing.
What are the two critical elements that align the optical fibers in a connection? -
CORRECT ANSWER - The ferrules and the mating adapter.
In an optical network, what is reflectance? - CORRECT ANSWER -
Reflectance is the reflected light from a single Fresnel reflection event.
VERIFIED AND WELL DETAILED ANSWERS | LATEST EXAM
UPDATE
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.
What do diameter differences between spliced fibers look like on an optical
time domain reflectometer (OTDR)? - CORRECT ANSWER - Gain in one
direction and high loss in the opposite direction.
Besides protection, what else must the coating on an optical fiber do? -
CORRECT ANSWER - Function over a wide temperature range; be
compatible with cable gels; adhere to the glass cladding over the lifetime of the
cable; and be mechanically strippable for splicing operations.
How do technicians know the specific type of single-mode fiber used in a
particular project? - CORRECT ANSWER - They have read the project's
specification records.
Which type of fiber-optic cable provides the most stable transport
characteristics and additional protection from stresses caused by macrobends
and microbends? - CORRECT ANSWER - Loose-tube cable.
What is a consideration for the use of ribbon fiber? - CORRECT ANSWER -
Ribbon fiber requires different tools and equipment to perform splicing.
What are the two critical elements that align the optical fibers in a connection? -
CORRECT ANSWER - The ferrules and the mating adapter.
In an optical network, what is reflectance? - CORRECT ANSWER -
Reflectance is the reflected light from a single Fresnel reflection event.
