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Gwenn AMICESenior Applications engineer
Fiber Optical Deployment and Troubleshooting With Great Power Comes Great Responsibility
Fiber links characterisation , certification and troubleshooting using Fiber certifier and multi-pulse iOLM
• With the needs for speed beyond the Gigabit Ethernet, optical fiber is replacing Cat 5/6/7 everywhere.
• In this session, we will give you 5 tricks that will help you to avoid 95% of the troubles in your fiber optic networks.
• The subjects covered in this technology session are the following: Cleaning and inspection of optical connectors, stress and macro-bends detection, link certification, accurate references, troubleshooting using intelligent optical link mapper tools or an OTDR.
Multimode or Singlemode fiber?
Source: Open Optics MSA Design Guide: http://www.openopticsmsa.org/pdf/Open_Optics_Design_Guide.pdf
Will Wide Band MM Fiber WBMMF (OM5?) enable coherent CFPs inside DC (4 colors @ 840-950 nm) or singlemode fiber will dominate?
10G line rate for 100G links, OM4 distance limit: 300 meters25G line rate for 100G links, OM4 distance limit: 100 meters100G line rate for 100G links, OM4 distance limit: 50 meters
Interfaces for Multimode
Multi-fiber connections• Due to Modal dispersion the maximum
achievable transmission rate in Multimode fiber is limited by the distance
Installation best practices• Where are the troubles coming from?
• Connector cleaningness and macrobending
95%
FIRST-TIME-RIGHT SYSTEM ACCEPTANCE STEPS
1 Connector inspection & cleaning
2 Cable certification, Tier-1 testing (OLTS @ new build)
3 Performance assessment, Tier-2 testing (OTDR/ iOLM) -
4 Documentation & reporting
Loss measurement in MM: Encircled flux, the new standard
› Encircled flux is a new method to define the launch conditions of a light source› EF measurement is based on the power distribution measurement on the
connector end face of the light source, reference jumper or conditioner
MM IL measurement is highly sensitive to the source launch conditionsExample: IL of a link varies greatly depending on whether a VCSEL or LED is used to perform the measurement
TIP#1: Make sure your unit is EF compliant
Why should anyone change?When upgrading from 1GigE to 10GigE and 100GigE loss budgets are much tighter
~ 3.5 dB @ 1GbE
~ 2.6 dB @ 10 GbE
~ 1.5dB @ 40/100GbE
• A 1dB uncertainty is lethal!
• Connector cleaning/ inspection is key!
PERFORMANCE EXPECTATION FROM MTP CONNECTION
MTP performance is primarily driven by three factors:
1. Selecting quality connector components: US Conec’s SM Elite and MM Elite grade of MTP connectors (optimized for 10G, 40G, 100G applications) have tighter tolerances on several key attributes, including guide pin & fiber hole diameter and location.
2. Achieving physical contact: Physical contact is heavily dependent on how well the MT ferrule is terminated and polished (i.e. the endface geometry). Physical contact is also dependent on using the proper spring force inside the MTP.
3. Ensuring endface cleanliness: Defects or debris on a physical contact connector can significantly degrade performance.
MM MT Elite®
Multimode MT FerruleSM MT Elite®
Single-mode MT Ferrule
Insertion loss (IL)
0.1dB Typical0.35dB Maximum2,3,5
0.10dB Typical0.35dB Maximum1,4,5
Return loss (RL)
> 20dB 5 > 60dB (8° Angle Polish) 5
1 As tested per ANSI/EIA-455-171 Method D32 As tested per ANSI/EIA-455-171 Method D13 As tested with proposed encircled flux launch condition on 50um fiber and 850nm per IEC 61280-4-14 Compliant with proposed IEC 61755-3-31/GRADE B5 For 32-fiber MM MTs, or 24-fiber SM MTs, performance assumes physical contact on all fibers. For these higher fiber counts, physical contact may be difficult to achieve.
New MTP-16TM Multi-fiber Optical Connector Supports Next Generation 400G Applications
MPO Connector endfaceMultiple fibers connector
• 3 levels of magnifications to cover a larger surface• MTP/MPO SM connectors are usually APC,MM are flat polished
100X 200X 400X
Low mag view:Allows to see what fiber is being inspected in High magnification
Blue Arrow indicates the fiber active in high mag view
“MF” mode
MPO Analysis as per IEC or Custom
TIPs #2To avoid 85% of the issues in the field:• Never assume that connectors are clean• Always inspect connectors• Always clean• Never use wet cleaning without drying the connector after• Never clean an MTP connector is it doesn’t need to be cleaned
Link Characterisationwhat does the standard say?
• ISO/IEC-14763.3• All optical fibre links must be tested for:
– Continuity and maintenance of polarity; – Length; – Propagation delay; – Optical attenuation of link, 2 x wavelengths, 2
x direction. • Using LSPM (OLTS) equipment. Where
LSPM results exceed the Power Loss Budget, the link shall be investigated with an OTDR to determine the location of the faulty component.
• TIA-568-C.3 • Source and power meter methodology should
be used to test end to end loss, link length and polarity check (Tier one )
• OTDR should be used to verify the loss and reflectance of localized event (Tier two) with a visual picture of the installed fiber optic network
OLTS vs. OTDR vs. iOLMOLTS OTDR iOLM
Number of technician required 2 1 1
Need to reference tester Yes No NoTechnical expertise needed to
perform testLow Medium to high Low
Number of acquisition/test per fiber 1An average of 3 to fully characterize all the
elements. For each acquisition, we can estimate an average of 30 sec/wavelength
1 (average of 45 sec, include all wavelengths)
Average test time per fiber* 3s dual λ bidir Typically 2 to 5 minutes depending on the link complexity and technician 's skills 45 seconds to 1 minute
Graphical representation of the link Link view, simplified Traditional graphical representation Link view detailed
Provide Insertion Loss Yes bidirectional Yes YesProvide Length of the fiber Yes Yes Yes
Automatic-Diagnostics Macrobend detection and pass/fail status Macrobend detection and pass/fail status Yes, global and individual pass/fail status plus diagnosis information for each failure
Allow locating faults No Yes YesLive testing No Yes Yes
Offer easy transpose fiber detection Yes No Yes with receive box
Loop back mode No No Yes
LS&PM uncertainty• The measurement uncertainty of LS&PM is mainly
induced by the reference process, the source stability and the uncertainty of the power meter
Typical Uncertainty with one patch cord reference: +/- 0.2dBTypical Uncertainty with two patch cord reference: +/- 0.35dB
DUPLEX Testing›Two fibers›FasTesT to power meter port›DataCenter approved method
SIMPLEX Testing›One fiber›FasTesT to FasTesT port›TelCo approved method
Methods
Optical loss test set: AutomatedReference methodology
http://www.thefoa.org/tech/ref/testing/5ways/fiveways.html
• Patent pending method• Allows to exclude the coupler loss from the reference values• GREATLY improves on IL accuracy• Extremely useful for short fiber test
Optical loss test set: Single fiber reference
TIP#3: Make sure your reference is valid
Single fiber reference.• The problem with Single fiber reference is that you need a second patchcord to
connect the remote patch panel .
CertificationSelecting certification standards
• The comities and standards you can choose from are grouped by categories.• You can select more than one standard and you can select standards from different
categories at the same time: the most restrictive values of the selected standards are then used to determine if the test results is a pass or a fail status.
End to end loss using the IOLM›In order to fully characterize a link end to end a launch fiber and a receive fiber need to be used.›The launch fiber will help the IOLM measuring the first connection.
›The receive fiber will help the IOLM measuring the last connection.›Launch and receive fiber needs to be from the same fiber type in order to reduce the uncertainty due to MFD mismatch.
End to end loss using the IOLM
TIP#4: Even if the loss is within the budget, distributed loss must be performed to
FTTH PtP Link: Loss measurements
32
FUT150m
Jumper5m
SC/PC
Launch150m
Receive500m
Jumper5m
SC/PC
iOLM
FTTH characterization (PON 1x32)
33
OTDR/IOLMLaunch150m
Fusion0.7dB
25mSC/APC
1:32
50m
SC/APC
Macrobend3dB 280m 800m
12mA1
A2
End to end loss using the IOLMIOLM Specification (dB)
Typical Notes
Link IL uncertainty 0.08 Link loss for 3m<L<500m.Single connector IL uncertainty 0.08 15m≤ L <500m
Reflectance uncertainty 0.75 From -45 to -65 dB
Short link ORL uncertainty 1(L<15 m). Includes two connectors and fibre loss
uncertainties. Events may be merged.
Certification using iOLM
Preset test configs Complete report with selected standard
Certified configurations
Thresholds values on report – Jan15
New challenges for the OTDR
Short links requirements:• High resolution• Fast acquisition time• Length measurement accuracy• Loss accuracy• Close events• Macro bend detection
Long links requirements:• High Dynamic range• High sensitivity• First 10Km high res• Macro bend detection• Loss accuracy• ORL accuracy
Data centers, FTTH, C-RAN, FTTA, FTTB, Backhaul, Front haul
DWDM, RAMAN, ROPA, 100G, 200G BackbonesR
esol
utio
n Dynam
icOTDR short pulses OTDR long pulses
Intelligent optical link mapper: IOLM
OTDR medium pulses… …
OP
TIM
OD
E
iOLM Loopback Uni-dir or Bi-Dir
Original measurement
Pass/Fail, display, SOR/iOLM files, and PDF report for Fiber 2
Pass/Fail, display, SOR/iOLM files, and PDF report for Fiber 1
Split
iLoopAutomatically separates the two fibers for individual results
iLOOP testing for FTTx or DC
© 2016 EXFO Inc. All rights reserved. | 41
• SAVE 50% ON YOUR TESTING TIME BY TESTING 2 FIBERS AT ONCE
• SPLIT MEASUREMENTS AND PASS/FAIL WITH NO POST-PROCESSING
• GET INDIVIDUAL FILES, REPORTS, SOR TRACES
• TEST FROM THE FDP OR PT
Macrobend detection in OLTS
TIP#5: In Single mode 1310 loss should be higher than 1550nm, if not you have a macro bend in your link