3 Basic Principal Of Fo Installation
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Transcript of 3 Basic Principal Of Fo Installation
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Basic Principal ofBasic Principal ofFO INSTALLATIONFO INSTALLATION
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Fiber Connector Types
EpoxyEpoxy-less
Pre-polished
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Splicing
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CONNECTING IT ALL TOGETHERCONNECTING IT ALL TOGETHER
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Mechanical Splices
Flat plate
V-groovedsubstrateButt jointed fiber
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Fusion Splices
Movable blockElectrodes
Fixed block
Fiber alignment groove
Fiber
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MT-RJ
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AMP SC Duplex Style Connector
Dust CoverDust Cover
Connector BodyConnector Body
Ferrule AssemblyFerrule Assembly
Crimp SleeveCrimp Sleeve
Cable BootCable Boot
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SC Connector (Epoxy)
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SC Connector (Epoxyless)
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ST Connector (Epoxyless)
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Fiber CleavingMethod A (Using Scribe Tool) Method B (Using Cleave Tool)
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Fiber Connector PolishingStep 1 : Air polishing Step 2 : Polishing on polishing plate
Procedure :Install the connector into the polishing bush and polish the connector tip using the 5 µm polishing film. With a thin layer of epoxy on the connector tip, replace the 5 µm with a 1 µm polishing film and continue polishing until the epoxy is totally removed.Finally, using 0.3 µm polishing film, polish until a smooth clear finishing on the fiber tip is achieved.
Procedure:Air polish the connector tip by gently rubbing the tip of the connector in small circles (or figure 8) until the cleaved fiber no longer makes scratches on the film.
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Inspecting The Fiber Termination
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Optical Fiber Cabling Systems
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Optical Fiber Parameters
• Optical Fiber Type• Cable Performance• Cabling Distance• Connector Performance• Splice Performance• System Performance• Performance Testing
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Optical Fiber Cable Types
• Horizontal Cabling− 50/125µm multimode − 62.5/125µm multimode
• Backbone Cabling− 50/125µm multimode − 62.5/125µm multimode− Singlemode
• Optical fiber types must be manufactured to meet attenuation specifications measured at both wavelengths specified for each type
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Optical Fiber Transmission Performance
Optical FiberCable Type
Wavelength(nm)
MaximumAttenuation
(dB/km)
Minimum Info.Transmission
Capacity(MHz•km)
50/125µm
62.5/125µm
SinglemodeInside Plant
SinglemodeOutside Plant
850
1300
850
1300
1310
1550
1310
1550
3.5
1.5
3.5
1.5
1.0
1.0
0.5
0.5
500
500
160
500
N/A
N/A
N/A
N/A
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Horizontal Cabling Distance
6 m 90 m 3 m
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Backbone Cabling Distance
HC/FD 1500m2500m
HC/FD 2000m3000m
IC/BD
500m
500m Multi-modeSinglemode
MC/CD EP
Cross-connect jumpers/patch cables = 20m
Telecommunications equipment cables = 30m
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Centralized Optical Fiber Cabling
300 meters90 meters
90 meters
WA
WA
CentralizedCross-
Connect
Pull-through
TC
Splice/Interconnect
TC
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TIA-568B.1 Maximum Fiber Distances50/125
(850MHz/1300MHz)62.5/125
(850MHz/1300MHz)10BASE-FL4 & 16 Mbps Token RingIEEE 802.12: Demand Priority
ATM @ 155 MbpsATM @ 622 Mbps
Fiber Channel (FC-PH) @ 266 Mbps
Fiber Channel (FC-PH) @ 531 MbpsFiber Channel (FC-PH) @ 1062 Mbps1000BASE-SX/LXFDDI LCF-PMD (low-cost)FDDI PMD100BASE-FX
Fiber Channel (FC-PH) @ 133 Mbps
2000m/---2000m/---
500m/2000m
1000m/2000m300m/500m
2000m/1500m1000m/---500m/---
550m/550m---/500m
---/2000m---/2000m
2000m/---2000m/---
500m/2000m
1000m/2000m300m/500m---/1500m
700m/1500m350m/---300m/---
220m/550m---/500m
---/2000m---/2000m
Network Platforms
ATM @ 52Mbps ---/3000m ---/3000m
---/1500m
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Connector Performance
• Attenuation Specifications- 0.75 dB max/mated pair- 1.5 dB max through a cross-connect
(based on 2 panels)
• Typical Attenuation- SC - .3 dB- ST - .3 dB
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Splice Performance
• Attenuation Specifications- 0.3 dB max- Fusion or Mechanical
• Typical Attenuation- Fusion - 0.1 dB- Mechanical - 0.2 dB
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Power Budgets - Definition
“The difference in optical power between what the transmitter delivers into a fiber and what
the receiver requires from the fiber to operate properly”
-19dBm
15dB
-36dBm
TX RX
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System Power Budget
TxTx RxRxInput powerLaunch Power (dBm)
Output Power = Power launched into a specific type fiber (i.e. 62./125)
Sensitivity = Minimum input power to obtain specified bit error rate
Example = Power -14 dBm to -19 dBm
Sensitivity = -14 dBm to -36 dBm
Power Budget : -19-(-36) =17dB
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Power Budgets - Units of Measure
• dB- A Measurement of Loss/Gain- In This Case a Positive Number
• dBm, dBu- A Measurement of Power as Compared
to One Milliwatt or One Microwatt- Normally a Negative Number
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Power Budgets - Elements for Calculation
• TX Power Out
• RX Sensitivity
• Margin (Average = @3 dB)
−Aging−Safety Aging- Safety
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Power Budgets - Calculation Example
TX Power: -19dBm
RX Sensitivity: -36dBm
Margin: 3dB
-19-(-36)-3Formula:
14dBPower Budget =
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Link Loss Budget
Elements for Calculation−Fiber Attenuation−Connector Loss−Splice Loss−Passive Component Loss
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Link Loss Budget
- _______ (Fiber Attenuation)
- _______ (Connector Loss)
- _______ (Splice Loss)
- _______ (Passive Component Loss)
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Link Loss Budgets - Calculation Example
RX
1Km(62.5/125µm)
Splice
Connectors
TX
3.5 dB1.5 dB0.3 dB0.0 dB5.3 dB
System loss measurement should always be less than the link loss budget
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Link Margin - Calculation Example
RX
1Km(62.5/125µm)
Splice
Connectors
TX
System Power Budget = 17 dB
Link Loss = 5.3 dB
Link Margin = 11.7
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Inspection & Test Equipment∗ Microscope : 100 - 200x
Visual Inspection of Connector End Faces
∗ Power Meters : Measure power (mW) and relative power (dB)
∗ OTDR : Measures length of fiber Attenuation Connector and SpliceReturn Loss
Look for :Multiple wavelengths - 850 -1300 -1550Short dead zoneAccuracy & resolution
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Testing Requirements
• Link Attenuation− Required
• Polarization− Recommended
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Horizontal Link Attenuation
Horizontal Link Measurement• Measured at only one Wavelength
− Either 850 nm or 1300 nm− Only one direction required
• ANSI/EIA/TIA-526-14A, Method B− One Reference Jumper
• Attenuation results less than 2.0 dB− Based on the loss of two connector pairs plus 90 meters of optical
fiber cable
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Centralized Link AttenuationCentralized Link Measurement• Measured at only one Wavelength
− Either 850 nm and 1300 nm− Only one direction required
• ANSI/EIA/TIA-526-14A, Method B− One Reference Jumper
• Attenuation results less than 2.9 dB − Based on the loss of two connector pairs plus 300m meters of optical
fiber cable and 1 splice in the TC
• Attenuation results less than 3.3 dB− Based on the loss of two connector pairs plus 300m meters of optical
fiber cable and an interconnection
A
B
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Centralized Link Attenuation Example300 meters(1.05 dB)
.75 dB(mated pair)
.75 dB(mated pair)
.3 dB(splice)
A
.75 dB(Interconnection)
.75 dB(mated pair)
.75 dB
B
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Backbone Link Attenuation Measurement
Backbone Link Measurement• Measured at both operating Wavelengths
− Multi-mode at 850 nm and 1300 nm− Singlemode at 1310 nm and 1550 nm− Only one direction required
• ANSI/EIA/TIA-526-14A, Method B− Multi-mode - one Reference Jumper
• ANSI/TIA/EIA-526-7, Method A.1− Singlemode - one Reference Jumper
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Backbone Link Attenuation SpecificationsBackbone Link Attn. = Cable Attn. + Connector Attn. + Splice Attn.
Connector Attenuation (mated pair) = 0.75 dB
Optical FiberCable Type
Wavelength(nm)
MaximumAttenuation
(dB/km)
50/125µm
62.5/125µm
SinglemodeInside Plant
SinglemodeOutside Plant
850
1300
850
1300
1310
1550
1310
1550
3.5
1.5
3.5
1.5
1.0
1.0
0.5
0.5
Splice Attenuation = 0.3 dB
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Backbone Link Attenuation Example
300 meters(1.05 dB)
.75 dB(mated pair)
.75 dB(mated pair)
.3 dB(splice)
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Optical Fiber Link Certification
EIA/TIA-526-14A EIA/TIA-526-7• Measures Optical Loss of Cable
Plant• Specifies Power Meters and OTDR• Indicates if Cable Plant Meets
Power Budget• For Singlemode Fiber Only• Includes Two Methods• Includes Three Methods for Power
Meters and One for OTDR
• Measures Optical Loss of Cable Plant
• Specifies Power Meters• Indicates if Cable Plant Meets
Power Budget• For Multimode Fiber Only• Includes Two Methods
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EIA-TIA-526-14A(B)/TIA/EIA-526-7(A.1)
Source Detectors
Reference
1P
Test Jumper 1
TestTest Jumper 1
2P
Cable PlantTest Jumper 2
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Troubleshooting
FlashlightMicroscope
OTDR
VFL Power Meters
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Common Failures/Faults• Polarity
− Patch/drop cables reversed
• Attenuation− Cable Breaks
− May be caused by exceeding tensile load or bend radius
− Core Mismatch/Misalignment− Caused by mixing different fiber types in the same channel− Caused by connecting hardware imperfections/installation/assembly
− Poor Splice− Poor cleave, fusion arc, mechanical assembly
− Poor Finish on Connector− Dust, chipped/cracked/pistoned fiber
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Loss Mechanisms in Connections
Loss from End SeparationLoss from Angular
MisalignmentLoss from Lateral Displacement
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OTDR Troubleshooting
Cable Plant
Dead Zone Fiber
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Backscatter plot from a fiber under test with an OTDR
Fiber end
Distancefromlaunch
Fiber
Faulty region ofhigh attenuation
Splice
Light pulselaunched into fiber
undertest
Reflectedpower Backscatter
Reflectionfrom joint
Fault loss
Fresnel end reflection
Time
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WHAT IS BACK REFLECTION ?WHAT IS BACK REFLECTION ?
Refractive Barriers Caused by Polishing
Air
Reflected Signals Travel Backward Toward Light Source
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ANGLED PC FERRULESANGLED PC FERRULES
Back Reflection is Directed Away from the Core and Cladding
8 ° Angle, PC PolishAngle PC (APC)
60dB
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Summary• Identified performance characteristics and industry
standard specifications of optical fiber types and connecting hardware
• Defined power budgets• Determined how to calculate unused margins• Identified attenuation specifications for both
horizontal and backbone optical fiber cabling links• Identified the industry standards methods for the
certification of an optical fiber cabling system• Determined how to recognize common faults in an
optical fiber cabling system