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Table of contents

Testing Theory - Performance of Optical Fiber Cabling............................................................. 3

Industry performance standards...................................................................................... 3
Network application standards......................................................................................... 6
Coming Soon....................................................................................................................11
Fluke Networks Fiber Optic Test and Troubleshooting Solutions...............................................12
Online Resources..............................................................................................................13
Testing Theory - Performance of Optical Fiber Cabling
Certification is the most complete form of field-testing. As alluded to earlier, the
certification test procedure ensures that the installed cabling conforms to the
transmission performance standards defined in the industry standards such as the
applicable International Organization for Standard/International Electrotechnical
Commission (ISO/IEC) and TIA standards.

Industry Performance Standards

Two groups of standards should be considered to obtain a complete specification and
ensure that the installed cabling will support the requirements for the intended network
applications. The goal of certification testing after all is to gain the confidence that the
cabling system will not be the source of any network malfunction even before the network
equipment is installed. The two groups of standards recognize each other’s requirements
but do not provide a perfect overlap.

Generic Installation Standards

The generic standards address the general installation rules and performance
specifications. The applicable standards are the ISO std 11801-1:2017(en) and ISO/
IEC 14763-3 Edition 2.0, Information Technology – Implementation and operation of
customer premises cabling – Part 3: Testing of optical fibre cabling, and the ANSI/TIA
568.3-D, Optical Fiber Cabling and Component Standard. The latter specifies performance
and transmission requirements for premises optical fiber cable, connectors, connecting
hardware, and patch cords. Transition methods used to maintain optical fiber polarity and

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ensure connectivity between transmitters and receivers using simplex, duplex, and array
connectivity are also described.
These standards address field-test specifications for post-installation transmission
performance which depends on cable characteristics, length, connecting hardware, cords,
cross-connect wiring, the total number of connections, and the care with which they are
installed and maintained. For example, severe cable bends, poorly installed connectors
and a very common problem – the presence of dust, dirt and other contaminants on the
end-face of fibers in connections – negatively influence link attenuation.

The installation standards specify as a minimum transmission performance that the

measured link loss be less than the allowed maximum (loss limit), which is based on
the number of connections, splices and the total length of optical fiber cable. This
certification must be executed with an accurate Optical Loss Test Set (OLTS) or a Light
Source and Power Meter (LSPM). These test tools will be described in more detail later
as well as the Optical Time Domain Reflectometer (OTDR). An OTDR provides a good
indication of total link loss but is not sufficiently accurate for link loss certification
testing. Certification includes the requirement of documentation of the test results;
this documentation provides the information that demonstrates the acceptability of the
cabling system or support of specific networking technologies.
The link attenuation allowance calculation:

Link Attenuation Allowance (dB) = Cable Attenuation Allowance (dB) + Connector

Insertion Loss Allowance (dB) + Splice Insertion Loss Allowance (dB)

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Where:
Cable Attenuation Allowance (dB) = Maximum Cable Attenuation Coefficient (dB/km) × Length (km)
Connector Insertion Loss Allowance (dB) = Number of Connector Pairs × Connector Loss Allowance (dB)
Splice Insertion Loss Allowance (dB) = Number of Splices × Splice Loss Allowance (dB)
Table 1 (see eBook #1 of this series) lists the cable attenuation coefficient by cable type; this coefficient
is 3.5 dB/km at 850 nm for all multimode optical fiber types recommended for premises cabling systems.
Indoor rated singlemode fiber has an attenuation coefficient of 1 dB/km or lower while outdoor rated
singlemode fiber has a coefficient of 0.5 dB/km or lower. The standards also specify the maximum
connector loss allowance as 0.75 dB and the maximum splice loss allowance as 0.3 dB. Well-executed
cabling installations should generally deliver connections that exhibit significantly lower connection
losses. The same statement applies to splice losses. Note that the length of the fiber link must be known
or must be measured by the test tool to determine the loss limit.

Table 2 shows an example application of the loss limit calculations. The calculation is performed for a 300
meter OM3 fiber link segment with just two end connectors and no splices that is used with an 850 nm
light source.
Max. loss per
Calculated loss
unit length or Length / number
(dB)
per item
Max. loss in fiber 3.5 dB/km 0.3 km 1.05
Max. loss in connections 0.75 dB 2 connections 1.5
Max. loss in splices 0.3 dB 0 splices 0.0
Link loss limit 2.55

Table 2 -Loss limit calculation for a 300 meter multimode link with 850 nm light source.

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Wavelength and directional requirements:

1. Horizontal cabling or Cabling Subsystem 1 link segments (TIA-568.3-D) need to be

tested in one direction at one wavelength, either 850 nm or 1300 nm for multimode,
and either 1310 nm or 1550 nm for single-mode.
2. Backbone/riser cabling (Cabling Subsystem 2 and Cabling Subsystem 3 link segments)
shall be tested in at least one direction at both operating wavelengths to account for
attenuation differences associated with wavelength. Multimode link segments shall
be tested at 850 nm and 1300 nm; singlemode link segments shall be tested at 1310
nm and 1550 nm. Links that use keyed connectors to implement the fiber polarity can
only be tested in the direction prescribed by the keying of the connectors.
.

Network Application Standards

For certification, the network application standards such as the IEEE standard 802.3
for Ethernet or the ANSI standard for Fiber Channel (FC) must also be considered.
High throughput applications (Gb/s range and above) require more stringent limits
on channel length and channel loss that is depending on the type and bandwidth
rating of the optical fiber and the light sources used in the network devices. Table 3
shows the maximum supported distance and the maximum allowable channel loss for a
number of common network applications and for the different fiber types we described
earlier in Table 1. The maximum channel length (maximum distance supported) is a
proxy specification for dispersion. As long as the channel length does not exceed the
maximum stated in the standard, dispersion will not cause a communication breakdown.

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Field certification shall verify that fiber optic channel length does not exceed the
maximum supported distance (the length limit). The installation standards discussed
above require the measurement of cable length in order to calculate the ‘maximum link
attenuation allowance’ but the installation standards impose a generic maximum length,
which may far exceed the length specified for the application. This means that ANSI/
TIA-568.3-D testing may not guarantee that your fiber application will work. ANSI/
TIA-568.3-D only guarantees the workmanship of the installation. ANSI/TIA-568.0-D
Section 1 cautions the user to consult application standards. In section 5.10.1 it states:
“Cabling lengths are dependent upon the application and upon the specific media chosen
(see Annex C). The length includes the cords and jumpers used for cross-connections,
interconnections, and connections at the equipment outlet.”

Tables 3 and 4 document that the length is limited and that it decreases for higher data
rate applications depending on the bandwidth rating of each fiber type (a function of the
modal dispersion characteristics of the fiber).

OS1 OS2
Wave- Dist. Loss Dist. Loss
Application
length (m) (dB) (m) (dB)
10GBASE-L 1310 10000 6.2 10000 6.2
40GBASE-LR4 1310 10000 6.6 10000 6.6
100GBASE-LR4 1310 10000 6.3 10000 6.3

Table 3 – Maximum Channel Distance and Loss for single mode optical fiber application by fiber type.

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 OM1 OM2 OM3 OM4 OM5
Wave- Dist. Loss Dist. Loss Loss Dist. Loss Dist. Loss
Application Dist. (m)
length (m) (dB) (m) (dB) (dB) (m) (dB) (m) (dB)
1000BASE-SX 850 275 2.6 550 3.6 800 4.5 880 4.8 n/a n/a
10GBASE-S 850 33 2.4 82 2.3 300 2.6 450 3.1 400 2.9
40GBASE-SR4 850 n/a n/a n/a n/a 100 1.9 125 1.9 150 1.5
100GBASE-SR4 850 n/a n/a n/a n/a 70 1.8 100 1.9 100 1.9
100GBASE-SR10 850 n/a n/a n/a n/a 100 1.9 125 1.9 150 1.5
10G Fiber Channel
1200-MX-SN-I 850 33 2.4 82 2.2 300 2.6 300 2.6 n/a n/a
(10,512 Mbaud)
16G Fiber Channel
1600-MX-SN 850 n/a n/a 35 1.6 100 1.9 125 1.9 n/a n/a
(10,512 Mbaud)

Table 4 – Maximum Channel Distance and Loss for multimode optical fiber application by fiber type.

Channel
Permanent link

Network Network
equipment equipment
CP
Fixed cabling
Equipment Equipment
cord cord
Patch cord

Figure 11 – The channel represents the end-to-end link connecting transmitter and receiver. The fixed cabling – a
subsegment of the channel – is called the permanent link. The figure shows a generic horizontal link model that
contains optional connections such as the CP (Consolidation Point).

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The channel is the total cabling link including all patch cords (also called equipment cords)
that link the active devices. Figure 11 depicts the difference between channel and permanent
link. The permanent link describes the link that is considered a permanent part of the building
or datacenter infrastructure. The network equipment is connected to the permanent link using
patch cords. Care should be taken to select cords made of the same fiber type as the permanent
link optical fiber cabling.

Often an optical fiber link is constructed with several segments or sections and the network
equipment is often not installed yet when the cabling installation is certified. It is not sufficient
to test each segment against the installation standards. Ensuring that the installed cabling
system will support the intended network application requires that the installed channels
(end-to-end fiber links) meet the length and loss requirements defined in the application
specification as shown in Tables 3 and 4.

You may select one of two methods to assure that the installed channel meets the application
requirements before you turn up the network service:

1. Calculate the channel loss by adding the data for each link segment in the channel and
adding the expected loss contribution of the interconnecting patch cords. ISO/IEC 14763-
3 Ed2: 2014 makes explicit assumptions about the loss of a TRC connection with a link
(0.5 dB for multimode fiber and 0.75 dB for singlemode fiber) versus the maximum loss of
connections made with commercial patch cords (0.75 dB for both multimode and singlemode
fibers).
2. Measure the channel loss as demonstrated in figure 12. The end-connections of the channel
– connections made with the network equipment – are now made with TRCs that introduce a
negligible loss. This method should be used when total fiber channels are tested and not just

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 segments thereof. Furthermore the test setup must include the final patch cords as well as the
TRCs. Keep in mind that the accuracy of the measurements will depend heavily on a correct
fiber reference setting.
Channel

Tester Tester
Main Unit Remote Unit
CP
Test reference
cord Patch cord Test reference
cord
Figure 12 – The end connections in Fig 12 are not part of the channel specification. By replacing the patch
cords with the Test Reference Cords (TRCs) for the channel loss and length measurement, the “error” in the loss
measurement is represented by the difference in length between one TRC and the sum of the two patch cords used
to complete the channel.

Optical fiber link polarity

Local area network installations support bi-directional communication by using separate optical
fibers in each direction. The cabling system shall provide means to maintain correct signal
polarity so that the transmitter on one end of the channel will connect to the receiver on the
other end of the channel. Several methods are used to maintain polarity for optical fiber cabling
systems. Guidelines are described and illustrated in Annex B of TIA-568-C.0. Duplex connector
types and array connector systems that allow the fiber ordering arrangement to be maintained
relative to the plug’s keying features should be selected.

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Coming Soon

Soon the following eBooks will become accessible:

#3: Optical Fiber Cabling Certification
Select the performance standard
Certification- Process and equipment requirements
Measurement units
Set the reference - principle
Launch conditions
#4: Fiber Certification with an OLTS in Practice

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 Inspection and Cleaning MPO Testing Loss Length Testing Plant Characterization and Troubleshooting
(Tier 1 Certification) (Tier 2 Certification)
Fluke Networks
Fiber Test and
Troubleshooting
Solutions
FI-500 FI-7000 FI-3000 Fiber Optic MultiFiber™ CertiFiber® Pro SimpliFiber® Pro VisiFault™ Fiber OptiFiber® OptiFiber® Pro
FiberInspector™ FiberInspector™ FiberInspector™ Cleaning Kits Pro Optical Loss Power Tester and Visual QuickMap™ Pro PON/FTTx
Micro Pro Ultra MPO Tester Test Set Fiber Test Kits Fault Locator OTDR HDR OTDR
Check end-face contamination      
or damage
End-face inspection grading     
Port Illumination  
Auto-focus  
Clean contamination 
Check connectivity      
Check polarity    
Verify loss over entire   
link to ensure loss
budget not exceeded
Dual-fiber loss testing   
Singlemode Tier 1 certification   
Multimode Encircled Flux EF compliant with EF TRC’s 
Compliant Tier 1 Certification at the
bulkhead
Locate faults    
Tier 2 certification  
Pass/fail results      
Document test results       
Fiber types supported Multimode MPO, MPO MPO, MPO Multimode Multimode Multimode Multimode Multimode Singlemode
Singlemode Multimode Multimode Multimode Singlemode Singlemode Singlemode Singlemode (1310, 1550,
Singlemode Singlemode Singlemode 1490 & 1625 nm)
Source type LED, FP Laser LED, FP Laser LED, FP Laser Laser Laser LED, FP Laser
Laser

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 Other highly technical resources:
To download the Fiber Test & Troubleshooting eBook visit:
www.flukenetworks.com/request/fiber-test-troubleshooting-ebook
To download the Twisted Pair Balance Measurements eBook visit:
www.flukenetworks.com/request/free-e-book-balance-measurements-handbook
Want to talk to an expert then locate you local contact number on:
www.flukenetworks.com/contact

Online Training Videos Cabling Chronicles Blog

These videos provide basic training for the Find out what’s new in the world of testing and
complete VersivTM Cabling Certification System. standards with articles written by Fluke Networks’
For each product, a set of videos cover the experts.
following topics:
www.flukenetworks.com/blog/cabling-chronicles
• Unboxing – what comes with the product and
what to do with it Knowledge Base
• Setting Up a Test Get the most out of your Fluke Networks
• Running a Test investment with tips and tricks plus product
updates from our team of support experts.
• Saving and Managing Results (using
LinkWare™ PC and LinkWare™ Live) www.flukenetworks.com/knowledge-base
www.youtube.com/FlukeNetworksVideo
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