FOA Reference Guide To Outside Plant Fiber Optics
And Study Guide To FOA Certification
Answers To Chapter Questions
Chapter 5 Quiz- OSP Optical Fiber
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. Singlemode fiber has a __________ light-carrying core than multimode fiber.
A. Smaller
B. Larger
C. Same size
ANSWER: A
The core of SM fiber is so small it only transmits one mode (ray) of light, thus it is "singlemode."
2. What is the approximate core size of 1300 - 1550 nm singlemode fiber?
A. 5 mm
B. 9 microns
C. 50 microns
D. 63.5 microns
ANSWER: B
The
correct fiber core size for 1300 - 1550 nm singlemode fiber is around 9
microns (see mode field diameter for a more technical definition).
There is SM fiber with a 5 micron core for 850 nm systems, but it is
rare.
3. Singlemode fiber has __________ bandwidth than multimode fiber.
A. More
B. Less
C. The same
ANSWER: B
Singlemode
fiber does not have problems with modal dispersion limiting its
bandwidth - it has very high bandwidth with typical laser sources.
4. What wavelengths are appropriate for use with singlemode fiber?
A. 650 & 850 nm
B. 850 & 1300 nm
C. 1310 & 1550 nm
D. 850 & 1490 nm
ANSWER: C
SM fiber is optimized for use in the range of 1310 to 1550 nm.
5. The diameter of the core in OM2 and OM3 multimode fiber is how large?
A. 50 microns
B. 62.5 microns
C. 62.5 mm
D. 9 mm
ANSWER: A
This is multimode fiber used for high speed transmission at 850 nm.
6. Which of the following fiber specifications is most important to the user and is an important factor in testing?
A. Attenuation
B. Bandwidth
C. Numerical aperture
D. Core-cladding concentricity
ANSWER: A
One always wants the fiber to have the lowest loss and the fiber attenuation is a major factor when calculating loss budgets.
7. The largest contributor to fiber attenuation is __________.
A. Absorption
B. Scattering
C. Bending losses
D. Microbends
ANSWER: B
Scattering
is the largest contributor to fiber attenuation. Since it decreases at
longer wavelengths, fiber is generally used in the infrared wavelength
range.
8.
Which fiber typically has the largest core?
A. POF
B. Multimode Step Index
C. Multimode Graded Index
D. Singlemode
ANSWER: A
POF has a large core, often 1 mm, for use in lighting and slow data links with inexpensive LEDs.
9. The loss of a singlemode fiber is lowest at __________.
A. 850 nm
B. 1300 nm
C. 1310 nm
D. 1550 nm
ANSWER: D
Fiber has lower loss at longer wavelengths, but 1550 nm is close to the longest wavelength for practical applications.
10. Which type of dispersion affects singlemode fiber as well as multimode fiber?
A. Modal
B. Differential
C. Chromatic
D. Polarization mode
ANSWER: C
Singlemode
fiber only supports one mode, so modal dispersion is not an issue. PMD
is only a problem with long SM links. Chromatic dispersion affects both
SM and MM fiber.
Multiple Response
Identify one or more choices that best complete the statement or answer the question.
11. Which types of dispersion needs to be tested in long singlemode fiber links?
A. Modal
B. Differential Modal
C. Chromatic
D. Polarization mode
ANSWER: C,D
CD and PMD are the issues for long SM links.
- Next: Lesson 6: Fiber Optic Cables
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