Chapter 2 - Introduction Flashcards
Define: Decibels (dB)
A ratio of the percentage of signal attenuation.
What is a relative measurement?
Decibels (dB)
___________, ___, and __________ are expressed as “dB”.
Attenuation, gain, and reflection
What is used to define fiber and cable attenuation at specific wavelengths?
“dB/km”
0 dBm = ___ mW
1.0
___ dBm = 2 mW
+3
___ dBm = 0.5 mW
-3
What is an absolute, objective measurement?
dBm
Power is expressed as?
dBm
dBm (input) - dBm (output) = _____
dB or Decibels
Kilometers (km) X ______ = Miles
0.62
Miles X _____ = Kilometers (km)
1.61
1,000,000,000 Quantity = _____ Power
10^(9)
What is the prefix for 1,000,000,000?
GIGA
What is the symbol for GIGA?
G
0.1 = ______ Power
10^(-1)
What is the prefix for 0.1?
DECI
What is the symbol for DECI?
d
0.000001 = _____ Power
10^(-6)
What is the prefix for 0.000001?
MICRO
What is the symbol for MICRO?
u
0.000000001 = _____ Power
10^(-9)
What is the prefix for 0.000000001?
NANO
What is the symbol for NANO?
n
What is a mode?
A discrete light path within the core of the Fiber between the transmitter and the receiver.
The number of _______ in a fiber will increase as the wavelength decreases.
modes
__________ fibers have a single light path at a single wavelength
Single-mode
__________ fibers have multiple light paths.
Multimode
What is attenuation?
The loss of light or signal power. It is expressed as dB. dB/km is loss referenced to a kilometer length of optical fiber.
What is the abbreviation for dBmW, a decibel (dB) relative to one milliwatt (mW) of power?
dBm
What is displayed on the vertical scale?
Attenuation
Dispersion
The general name for any of a group of phenomena that cause the pulse of an optical signal to be spread out in time, so that it becomes increasingly difficult to tell one pulse from another.
What is it when the horizontal scale distorts the pulse or signal, limiting system bandwidth?
Dispersion
What types of dispersion is single-mode systems limited by?
chromatic and polarization mode dispersion
What type of dispersion limits bandwidth in multimode systems?
Modal dispersion
What is reflection?
Affects the operation of lasers used in transmitters, thereby affecting signal quality.
Causes of __________ are connectors, mechanical splices, open fiber ends, and lensed components.
Reflection
When a light beam changes direction at an interface between two dissimilar media and returns into the medium from which it originated.
Reflection
What is coating?
Protects against abrasion and assures high strength.
What is cladding?
Glass or plastic, with a lower index of refraction. Keeps the optical signal with the core.
What is core?
The glass or plastic in which light propagates through the fiber. Has a higher index of refraction than the cladding.
What is MFD?
Mode Field Diameter
The diameter of the spot of light transmitted through a single-mode fiber.
Mode Field Diameter
OM2/3/4/5 is what type of multimode?
50/125 Multimode (50 core/125 cladding)
OM1 is what type of multimode?
62.5/125 - 62.5 core/125 cladding
G.652 & G655 is what type of fiber?
Single mode (8-10 core/125 cladding)
When was the first North American commercial fiber optic system installed?
1975
What is a mode in an optical fiber?
Discrete light path within the core of the fiber between the transmitter and the receiver.
What are the 3 C’s of an optical fiber?
Coating, Cladding, & Core
What are the three critical factors to be considered when working with a fiber optic network?
Attenuation, Dispersion, & Reflection
What does the acronym ITU represent?
International Telecommunication Union
What are the three components of an optical transmission system?
Transmitter, Receiver, & Physical plant
What are the two most commonly used sizes of multimode cores?
50 & 62.5
What unit of measurement is used to measure and express wavelengths?
Nanometer (nm)
What unit of measurement is used to denote the size of a fiber’s core, cladding, and coatings?
Micron (um)
What is the outside diameters of single-mode and multimode claddings?
125
