ETA FIBER CERTIFICATION TECHNICIAN
(FOT) WOAC EXAM QUESTIONS AND
ANSWERS 2026 - 2027
Testing Equipment & Procedures (OLTS, OTDR, Power Meter)
Q1. A _____________ is used with an overfilled light source when testing loss in a multimode fiber
and is placed on the ____________ MQJ.
Answer: Mandrel Wrap / Light Source
Rationale: A mandrel wrap (also called a mode filter) strips out high-order modes from an overfilled
launch. It is wrapped around the launch cord (the Measurement Quality Jumper connected to the light
source) to ensure stable, compliant test conditions per TIA standards.
Q2. Back reflections from a mechanical interconnection can interfere with the operation of a
__________________.
Answer: singlemode laser
Rationale: Singlemode lasers are coherent and highly sensitive to reflected light. Back reflections can
cause instability, wavelength shifts, or damage to the laser source.
Q3. Checking the power at the _________________ should be the first test that is done when
troubleshooting a network problem.
Answer: receiver
Rationale: The receiver is where the signal ends. If power at the receiver is within spec, the problem is
likely elsewhere (e.g., electronics). Low power indicates a fiber link issue.
Q4. Tier 1 testing accomplishes insertion loss, cable length, polarity verification, and overall fiber link
attenuation and reflectance loss at connectors and splices. (True/False)
Answer: True
Rationale: Tier 1 testing per ANSI/TIA-568 uses an OLTS (Light Source & Power Meter) to verify these
basic parameters. Tier 2 adds OTDR trace analysis.
,Q5. A mechanical splice will be identified on an OTDR trace as a _______________ event.
Answer: reflective
Rationale: Mechanical splices use index matching gel and precise alignment, but the small air gap
creates a refractive index change that reflects a small amount of light, appearing as a distinct peak
(reflective event) on the OTDR trace.
Q6. Fusion splices produce very small back reflections that most times can't be seen on the OTDR
trace. (True/False)
Answer: True
Rationale: Fusion splicing melts fibers together, creating a continuous glass-to-glass interface with
virtually no air gap. This results in negligible back reflection, often invisible on OTDR traces.
Q7. When an OTDR is being used to determine insertion loss where the cursors are placed on opposite
sides of the event, the method is called _____________.
Answer: two point method
Rationale: The two-point method places cursors before and after an event (splice, connector). The OTDR
calculates loss as the difference in backscatter levels between the two points.
Q8. An OTDR screen displays distance or length on the ____________ axis and power or amplitude on
the __________ axis.
Answer: horizontal / vertical
Rationale: Standard OTDR traces show distance (horizontal) increasing left-to-right, while signal power
(vertical) decreases due to attenuation. Events appear as dips or peaks.
Q9. Testing short length cables with an OTDR can produce anomalous events called ____________.
Answer: Ghosts
Rationale: Ghosts are false reflective events caused by multiple reflections bouncing between two real
reflective events (like connectors). They appear at twice the distance of the real event and can confuse
analysis if not recognized.
Q10. If an IOR of 1.4965 is entered into the OTDR and the actual IOR of the cable is 1.4623; will the
OTDR display a longer or shorter cable length than the actual cable length?
Answer: Shorter
, Rationale: Distance calculation is: Distance = (c × time) / (2 × IOR). If entered IOR is higher than actual,
the OTDR over-corrects, showing a shorter distance. This is a common setup error.
Q11. What is the loop diameter required to serve as a mode filter when testing a singlemode fiber
with an OLTS?
Answer: 30mm
Rationale: Per ANSI/TIA-526-14, a 30mm diameter mandrel (or ~10 turns around a 30mm cylinder) is
required to filter higher-order modes when testing singlemode fiber with an OLTS.
Q12. After referencing the OLTS using the one (1) Jumper Reference method, a second MQJ is coupled
to the reference MQJ and connected to the power meter. The expected loss of the connected pair
should be less than ____________.
Answer: 0.5 dB
Rationale: A single mated connector pair (reference jumper to test jumper) should have loss under 0.5
dB for multimode and under 0.3 dB for singlemode per TIA standards. 0.5 dB is the common acceptance
threshold.
Q13. If the technician needs to find the total loss of a fiber plant cable with connectors at both ends,
he needs to reference his OLTS using:
Answer: One (1) Jumper Reference / Method B
Rationale: Method B (one jumper) is the standard for installed link testing. It sets the reference at the
end of a single test jumper, then the link is inserted between that jumper and the power meter. This
accounts for both end connectors.
Q14. A _______________ is used to detect light propagating down a fiber by utilizing the effect of a
non-destructive macro bend.
Answer: fiber identifier
Rationale: A fiber identifier clamps onto a fiber, creating a safe macro-bend that leaks a small amount of
light. It detects traffic direction and presence without damaging the fiber or interrupting service.
Q15. What documentation should be recorded for OTDR results?
Answer: Test procedure and method used
(FOT) WOAC EXAM QUESTIONS AND
ANSWERS 2026 - 2027
Testing Equipment & Procedures (OLTS, OTDR, Power Meter)
Q1. A _____________ is used with an overfilled light source when testing loss in a multimode fiber
and is placed on the ____________ MQJ.
Answer: Mandrel Wrap / Light Source
Rationale: A mandrel wrap (also called a mode filter) strips out high-order modes from an overfilled
launch. It is wrapped around the launch cord (the Measurement Quality Jumper connected to the light
source) to ensure stable, compliant test conditions per TIA standards.
Q2. Back reflections from a mechanical interconnection can interfere with the operation of a
__________________.
Answer: singlemode laser
Rationale: Singlemode lasers are coherent and highly sensitive to reflected light. Back reflections can
cause instability, wavelength shifts, or damage to the laser source.
Q3. Checking the power at the _________________ should be the first test that is done when
troubleshooting a network problem.
Answer: receiver
Rationale: The receiver is where the signal ends. If power at the receiver is within spec, the problem is
likely elsewhere (e.g., electronics). Low power indicates a fiber link issue.
Q4. Tier 1 testing accomplishes insertion loss, cable length, polarity verification, and overall fiber link
attenuation and reflectance loss at connectors and splices. (True/False)
Answer: True
Rationale: Tier 1 testing per ANSI/TIA-568 uses an OLTS (Light Source & Power Meter) to verify these
basic parameters. Tier 2 adds OTDR trace analysis.
,Q5. A mechanical splice will be identified on an OTDR trace as a _______________ event.
Answer: reflective
Rationale: Mechanical splices use index matching gel and precise alignment, but the small air gap
creates a refractive index change that reflects a small amount of light, appearing as a distinct peak
(reflective event) on the OTDR trace.
Q6. Fusion splices produce very small back reflections that most times can't be seen on the OTDR
trace. (True/False)
Answer: True
Rationale: Fusion splicing melts fibers together, creating a continuous glass-to-glass interface with
virtually no air gap. This results in negligible back reflection, often invisible on OTDR traces.
Q7. When an OTDR is being used to determine insertion loss where the cursors are placed on opposite
sides of the event, the method is called _____________.
Answer: two point method
Rationale: The two-point method places cursors before and after an event (splice, connector). The OTDR
calculates loss as the difference in backscatter levels between the two points.
Q8. An OTDR screen displays distance or length on the ____________ axis and power or amplitude on
the __________ axis.
Answer: horizontal / vertical
Rationale: Standard OTDR traces show distance (horizontal) increasing left-to-right, while signal power
(vertical) decreases due to attenuation. Events appear as dips or peaks.
Q9. Testing short length cables with an OTDR can produce anomalous events called ____________.
Answer: Ghosts
Rationale: Ghosts are false reflective events caused by multiple reflections bouncing between two real
reflective events (like connectors). They appear at twice the distance of the real event and can confuse
analysis if not recognized.
Q10. If an IOR of 1.4965 is entered into the OTDR and the actual IOR of the cable is 1.4623; will the
OTDR display a longer or shorter cable length than the actual cable length?
Answer: Shorter
, Rationale: Distance calculation is: Distance = (c × time) / (2 × IOR). If entered IOR is higher than actual,
the OTDR over-corrects, showing a shorter distance. This is a common setup error.
Q11. What is the loop diameter required to serve as a mode filter when testing a singlemode fiber
with an OLTS?
Answer: 30mm
Rationale: Per ANSI/TIA-526-14, a 30mm diameter mandrel (or ~10 turns around a 30mm cylinder) is
required to filter higher-order modes when testing singlemode fiber with an OLTS.
Q12. After referencing the OLTS using the one (1) Jumper Reference method, a second MQJ is coupled
to the reference MQJ and connected to the power meter. The expected loss of the connected pair
should be less than ____________.
Answer: 0.5 dB
Rationale: A single mated connector pair (reference jumper to test jumper) should have loss under 0.5
dB for multimode and under 0.3 dB for singlemode per TIA standards. 0.5 dB is the common acceptance
threshold.
Q13. If the technician needs to find the total loss of a fiber plant cable with connectors at both ends,
he needs to reference his OLTS using:
Answer: One (1) Jumper Reference / Method B
Rationale: Method B (one jumper) is the standard for installed link testing. It sets the reference at the
end of a single test jumper, then the link is inserted between that jumper and the power meter. This
accounts for both end connectors.
Q14. A _______________ is used to detect light propagating down a fiber by utilizing the effect of a
non-destructive macro bend.
Answer: fiber identifier
Rationale: A fiber identifier clamps onto a fiber, creating a safe macro-bend that leaks a small amount of
light. It detects traffic direction and presence without damaging the fiber or interrupting service.
Q15. What documentation should be recorded for OTDR results?
Answer: Test procedure and method used
