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Fiber Optics

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verickle's version from 2016-07-13 09:56

Section

Question Answer
Multimode850nm, 1310nm
Single mode1310nm, 1550nm
Fiber to the home/business1600-1625nm
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Definitions

Question Answer
Attenuationloss of power introduced by the fiber
Scatteringprimary loss factor over the three wavelength ranges
Absorbtionsecond loss factor, a composite of light interaction with the atomic structure of the glass
Macrobendingloss caused by the light mode breaking up and escaping into the cladding when the fiber bend becomes too tight
Microbendinga type of loss caused by mechanical stress placed on the fiber strand, usually in terms of deformation resulting from too much pressure being applied to the cable
DispersionA phenomenon in which the light pulse spreads out in time as it propagates along the fiber strand.
Modal dispersionThe broadening of a pulse due to different path lengths taken through the fiber by different modes.
Chromatic dispersionThe broadening of a pulse due to different propagation velocities of the spectral components of the light pulse.
Polarization mode dispersionThe broadening of a pulse due to the different propagation velocities of the X and Y polarization components of the light pulse.
IsolatorsAn inline passive device that allows optical power to flow in one direction only.
AttenuatorsUsed to reduce the received signal level (RSL). They are available in fixed and variable configurations.
Branching devicesUsed in simplex systems where a single optical signal is divided and sent to several receivers, such as point-to-multipoint data or a CATV distribution system.
SplittersUsed to split, or divide, the optical signal for distribution to any number of places.
Wavelength division multiplexersCombine or divide two or more optical signals, each having a different wavelength. They are sometimes called optical beam splitters.
Optical-line amplifiersAnalog amplifiers. Placement can be at the optical transmitter output, midspan, or near the optical receiver.
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Glossary

Question Answer
AbsorptionLight interaction with the atomic structure of the fiber material; also involves the conversion of optical power to heat
BackboneThe primary path for data traffic to and from destinations and sources in the campus network
Chromatic DispersionThe broadening of a pulse due to different propagation velocities of the spectral components of the light pulse
CladdingMaterial surrounding the core, which must have a lower index of refraction to keep the light in the core
Dense Wavelength Division Multiplex (DWDM)Incorporates the propagation of several wavelengths in the 1550-nm range for a single fiber
DispersionBroadening of a light pulse as it propagates through a fiber strand
Dispersion Compensating FiberActs like an equalizer, canceling dispersion effects and yielding close to zero dispersion in the 1550-nm region
Distributed Feedback (DFB) LaserA more stable laser suitable for use in DWDM systems
DLDiode laser
DSDigital signal
DSLDigital subscriber line
EventA disturbance in the light propagating down a fiber span that results in a disturbance on the OTDR trace
Fiber Bragg GratingA short strand of modified fiber that changes the index of refraction and minimizes intersymbol interference
Fiber Cross-connectOptical patch panel used to interconnect fiber cables
Fiber, Light Pipe, GlassTerms used to describe a fiber-optic strand
FTTBFiber to the business
FTTCFiber to the curb
FTTDFiber to the desktop
FTTHFiber to the home
Fusion SplicingA long-term method where two fibers are fused or welded together
GBICGigabit interface converter
Graded-index FiberThe index of refraction is gradually varied with a parabolic profile
ICInterconnect fibers branch exchange-item D shows the jumpers connecting the main fiber cross-connect (item B) to the active equipment (item C)
IDCIntermediate distribution closet
Index-matching GelA jellylike substance that has an index of refraction much closer to glass than to air
Infrared LightLight extending from 680 nm up to the wavelengths of the microwaves
IsolatorAn inline passive device that allows optical power to flow only in one direction
LEDLight-emitting diode
Logical Fiber MapShows how the fiber is interconnected and data is distributed throughout a campus
Long HaulThe transmission of data over hundreds or thousands of miles
MacrobendingLoss due to light breaking up and escaping into the cladding
Mechanical SplicesTwo fibers joined together with an air gap, thereby requiring an index-matching gel to provide a good splice
MicrobendingLoss caused by very small mechanical deflections and stress on the fiber
mmMultimode
Modal DispersionThe broadening of a pulse due to different path lengths taken through the fiber by different modes
Mode Field DiameterThe actual guided optical power distribution, which is typically a micron or so larger than the core diameter; single-mode fiber specifications typically list the mode field diameter.
Multimode FiberA fiber that supports many optical waveguide modes
Numerical ApertureA measure of a fiber's ability to accept light
Optical EthernetEthernet data running over a fiber link
Optical SpectrumLight frequencies from the infrared on up
Physical Fiber MapShows the routing of the fiber but also shows detail about the terrain, underground conduit, and entries into buildings
Polarization Mode DispersionThe broadening of a pulse due to the different propagation velocities of the X and Y polarization components of the light pulse
Pulse DispersionStretching of received pulse width because of multiple paths taken by the light
Received Signal Level (RSL)The input signal level to an optical receiver
Refractive IndexRatio of the speed of light in free space to its speed in a given material
SC, ST, FC, LC, MT-RJTypical fiber connectors on the market
ScatteringCaused by refractive index fluctuations; accounts for 96 percent of attenuation loss
Single-mode FiberFiber cables with core diameters of about 7-10 μm; light follows a single path
smSingle mode
SONET/SDHSynchronous optical network; protocol standard for optical transmission in long-haul communication/synchronous digital hierarchy
STSSynchronous transport signals
Tunable LaserLaser in which the fundamental wavelength can be shifted a few nanometers, ideal for traffic routing in DWDM systems
Vertical Cavity Surface Emitting Lasers (VCSELs)Lasers with the simplicity of LEDs and the performance of lasers
XENPAK, XPAK, X2, XFP, SFP+The ten gigabit interface adapter
Zero-dispersion WavelengthPoint where the dispersion is actually zero
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SONET Hierarchy Data Rates

Question Answer
OC-151.840Mbps
OC-3155.52Mbps
OC-12622.080Mbps
OC-482.48832Gbps
OC-1929.95328Gbps
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SONET Hierarchy Capacity

Question Answer
OC-128DS-Is or DS-3
OC-384DS-Is or 3 DS-3s
OC-12336 DS-1s or 12 DS-3s
OC-481344 DS-1s or 48 DS-3s
OC-1925376 DS-Is or 192 DS-3s
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Ethernet Standards

Question Answer
10BASE10 megabits
100BASE100 megabits
1000BASE1000 megabits
10GBASE10,000 megabits
40GBASE40,000 megabits
100GBASE100,000 megabits
BASEbaseband
Ttwisted-pair cable
Kcopper backplane
Cbalanced copper cable
Foptical cable
Btwo wavelengths over a single optical cable
Sshort-range multi-mode optical cable (less than 100 m)
Llong-range single- or multi-mode optical cable (100 m to 10 km)
Eextended-range optical cable (10 km to 40 km)
Zlong-range single-mode cable at a higher wavelength
X4B/5B block coding for Fast Ethernet or 8B/10B block coding for Gigabit Ethernet
R64B/66B block coding
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Optical Ethernet Numerics

Question Answer
10BASE-F10Mbps Ethernet over fiber—generic specification for fiber
10BASE-FB10Mbps Ethernet over fiber—part of the IEEE 10BaseF specification; segments can be up to 2 km in length
10BASE-FL10Mbps Ethernet over fiber—segments can be up to 2 km in length; it replaces the FOIRL specification.
10BASE-FPA passive fiber star network; segments can be up to 500 m in length
100BASE-FXA 100Mbps fast Ethernet standard that uses two fiber strands
1000BASE-LXGigabit Ethernet standard that uses fiber strands using long-wavelength transmitters
1000BASE-SXGigabit Ethernet standard using short-wavelength transmitters
10GBASE-R10 gigabit (10.325Gbps) Ethernet for LANs
10GBASE-W10 gigabit (9.95328Gbps) Ethernet for WANs using OC-192 and SONET Framing
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The Fiber Color-code for the Twelve Fibers in a Bundle

Question Answer
1/2Blue/Orange
3/4Green/Brown
5/6Slate/White
7/8Red/Black
9/10Yellow/Violet
11/12Rose/Aqua Marine
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The basic elements of a fiber-optic communication system

Question Answer
1Fiber
2Optical light source
3Photosensitive detection
4Efficient optical connectors
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