Lesson #5, Optical Fiber
FOA Reference Guide To Fiber Optics
And Study Guide To FOA Certification
Answers To Chapter Questions
Chapter 5 Quiz-Fiber
MULTIPLE CHOICE
1. ANS: A
Singlemode fiber cores are much smaller than multimode fibers so they only can carry one mode of light.
2. ANS: B
Typical singlemode fiber has a core size around 9 microns.
3. ANS: A
Since it carries only one mode, SM fiber suffers no modal dispersion which limits MM fiber and has much higher bandwidth.
4. ANS: B
MM fiber operates at 850 and 1300 nm, while singlemode fiber is optimized for 1310 and 1550 nm.
5. ANS: A
OM2 and OM3 (laser-optimized) fiber has a 50 micron core.
6. ANS: A
Attenuation of the fiber contributes to the loss of the cable plant, along with connector losses.
7. ANS: B
Scattering is the major cause of fiber attenuation.
8. ANS: A
Most POF is large core step-index fiber, with a core ~1mm.
9. ANS: A
Scattering
is higher at shorter wavelengths, causing fiber attenuation of about 3
dB/km at 850 nm but only 1 dB/km at 1300 nm. MM fiber is rarely used at
1550 nm.
10. ANS: C
Chromatic
dispersion, caused by the fact that the speed of light in glass is a
function of wavelength, affects both SM and MM fiber.
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