DCI Fiber Optic Installation 2 — Questions and Answers
Question 1: What is the minimum bend radius typically allowed for a standard single-mode fiber optic cable during installation?
- 10 times the cable diameter
- 20 times the cable diameter (Correct answer)
- 5 times the cable diameter
- 50 times the cable diameter
Correct answer: 20 times the cable diameter
The minimum bend radius during installation is typically 20 times the cable diameter to prevent microbending losses and physical damage.
Question 2: Which tool is specifically used to cleave fiber optic strands before splicing?
- Fiber stripper
- Optical power meter
- Precision cleaver (Correct answer)
- OTDR unit
Correct answer: Precision cleaver
A precision cleaver scores and snaps the fiber to create a flat, perpendicular end-face required for low-loss splicing.
Question 3: When pulling fiber through conduit, what is the maximum pulling tension typically allowed for a standard 6-fiber loose-tube cable?
- 600 lbf
- 100 lbf
- 200 lbf (Correct answer)
- 400 lbf
Correct answer: 200 lbf
Most standard loose-tube cables have a rated pulling tension of approximately 200 lbf (pounds-force) to avoid stressing the fibers.
Question 4: What does an OTDR trace's 'dead zone' refer to?
- A section of fiber with no signal at all
- The area near the launch end where reflections mask real events (Correct answer)
- A splice point with zero loss
- The far end reflection of the fiber
Correct answer: The area near the launch end where reflections mask real events
The dead zone is the region immediately after the OTDR launch pulse where the receiver is saturated and cannot detect nearby events.
Question 5: Which fiber optic connector type uses a push-pull latching mechanism and is commonly used in high-density patch panels?
- SC
- ST
- FC
- LC (Correct answer)
Correct answer: LC
The LC (Lucent Connector) uses a push-pull latch and has a smaller 1.25 mm ferrule, making it ideal for high-density applications.
Question 6: What is 'chromatic dispersion' in a fiber optic cable?
- Signal loss due to fiber bending
- The spreading of a light pulse because different wavelengths travel at different speeds (Correct answer)
- Reflection at a connector end-face
- Cross-talk between adjacent fibers
Correct answer: The spreading of a light pulse because different wavelengths travel at different speeds
Chromatic dispersion occurs because different wavelengths of light propagate at slightly different velocities, causing pulse broadening over distance.
Question 7: When installing fiber optic cable in a plenum space, which cable jacket type is required?
- OFNR (riser-rated)
- OFNP (plenum-rated) (Correct answer)
- LSZH (low-smoke zero-halogen)
- Standard PVC jacket
Correct answer: OFNP (plenum-rated)
OFNP (Optical Fiber Nonconductive Plenum) cable is required in plenum spaces because it produces low smoke and does not spread flames through HVAC airflows.
DCI Fiber Optic Installation 2
What is the minimum bend radius typically allowed for a standard single-mode fiber optic cable during installation?