Deck 3: Physical Layer Cabling: Fiber Optics

Question 1

When there is an abrupt change in the refractive index from the core to the cladding in fibers,this is:

A)Due to the actual guided optical power
B)Called step-index fiber
C)Used for zero dispersion applications
D)Also called graded index

Answer 1

B

Question 2

DWDM does which of the following?

A)Incorporates the propagation of several wavelengths in the 1550-nm range for a single fiber
B)Incorporates the propagation of several wavelengths in the 1350-nm range for a single fiber
C)Incorporates the propagation of several wavelengths in the 850-nm range for a single fiber
D)All of these answers are correct.

Answer 2

A

Question 3

What is the broadening of a pulse due to the different propagation of the spectral components of the light pulse called?

A)Chromatic dispersion
B)Modal dispersion
C)Polarization mode dispersion
D)Diffusion

Answer 3

A

Question 4

What is the broadening of a pulse due to the different path lengths taken through the fiber by different modes called?

A)Chromatic dispersion
B)Polarization mode dispersion
C)Diffusion
D)Modal dispersion

Question 5

What are the light waves just below the frequencies in the visible spectrum extending up called?

A)Sub-light waves
B)Refractive waves
C)Multimode waves
D)Infrared light waves
E)Polar waves

Question 6

What is the optical patch panel used to interconnect fiber cables called?

A)Fiber splice
B)Optical combiner
C)Fiber cross-connect
D)Optical splitter

Question 7

A 50/125 fiber is used for single-mode applications.

Question 8

What bit rate is possible when an OC-1 is carrying a DS-3 signal?

A)51.84Mbps
B)100Mbps
C)300Mbps
D)500Mbps

Question 9

Single-mode fiber cables have a core diameter of about 7-10 micrometers.

Question 10

Graded-index fiber was developed to do which of the following?

A)Overcome OH peaks
B)Increase bandwidth
C)Overcome pulse-dispersion problems
D)Enable WDM applications

Question 11

What is the broadening of a light pulse due to the different propagation velocities of the X and Y polarization components of the light pulse called?

A)Modal dispersion
B)Polarization mode dispersion
C)Chromatic dispersion
D)Diffusion

Question 12

Conventional high-speed Ethernet networks operating over fiber are which of the following?

A)Of limited use in modern LANs
B)Being replaced by SONET
C)Called optical Ethernet
D)Being replaced by ATM

Question 13

When SONET is in use,what happens to the signal when it is with the optical carrier?

A)It is encrypted.
B)It is boosted.
C)It is cleaned.
D)It is encapsulated.

Question 14

How many DS-3 signals is one OC-1 capable of carrying?

A)1
B)2
C)3
D)4

Question 15

What is a measure of a fiber's light acceptance?

A)Dispersion
B)Numerical aperture
C)Refractive index
D)Mode field diameter

Question 16

"Step index" refers to which of the following?

A)The abrupt change in the refractive index from core to cladding
B)The abrupt change in the refractive index for the core
C)The abrupt change in the graded index from core to cladding
D)The abrupt change in the graded index for the core