Outside plant fiber optic networks are getting faster. Upgrading older cable plants to higher speeds or testing new installations to ensure they can support future needs requires testing fibers more extensively—a process called fiber characterization. How well do you understand it?
1. 1. Some fiber optic cables have been in use for ______ years or more.
2. 2. When those early fibers were installed, networks operated at speeds of ______.
A. Up to 140 megabits per second (Mbps)
B. 140–405 Mbps
C. >1 gigabit per second (Gbps)
D. >2.5 Gbps
3. 3. Today’s typical new fiber optic network operates at speeds in the ______ range.
A. 1–10 Gbps
B. 10–100 Gbps
C. 40–400 Gbps
D. 1 terabit per second (Tbps)
4. 4. At network speeds above 10 Gbps, ______ becomes a limiting factor and should be tested.
5. 5. Chromatic dispersion (CD) is caused by ______.
A. The light of different wavelengths traveling at different speeds
B. Speed variations depending on source power
C. Stress in optical fiber cables
D. High connector loss
6. 6. Polarization mode dispersion (PMD) may be caused by ______.
A. The size and shape of the fiber core
B. Stress on the fiber
C. The material composition of the fiber
D. All of the above
7. 7. Both CD and PMD can be corrected by using special compensating fibers.
8. 8. The first test for characterizing an installed fiber is ______.
A. Inspect connectors for condition and cleanliness
B. Visual fault location
C. Insertion loss
D. Optical time-domain reflectometer (OTDR) traces
9. 9. The attenuation of the fiber over a broad wavelength range is needed for fibers that are to be used for______.
A. Speeds above 10 Gbps
B. Dense wavelength division multiplexing
C. Repeaters using fiber amplifiers
D. Distances over 30 kilometers
10. 10. The pass/fail characteristics for CD and PMD test results on a cable plant may be determined by ______.
A. Calculated values from fiber specifications
B. Specified limits for various networks such as 100-Gbps ethernet
C. An analysis of test data and its uncertainty
D. Any or all of the above