White Paper

March 2012

RANDOM MATING ILVS.
IL BY MASTER JUMPER
Ky Ly - Senior Staff Engineer

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RANDOM MATING ILVS.
IL BY MASTER JUMPER

Contents

4

Introduction

4

Insertion Loss5

Random Mating

5

Connector IL Difference

7Solution

8

Conclusion

Insertion loss

Introduction
The best laid plans of mice and men often go awry. Whetherit is a System Designer, System Installer or Service Engineer,
they all rely on connectorized fiber optic patchcords
deployed into the field to meet the required performance
expectations. Even when the individual components
comply with industry standards, performance can still fallshort of expectations.
Typically, Insertion Loss (IL) and Return Loss (RL) performance
shortfalls are merely symptoms of the fiber optics industry’s
Achilles’ heel, namely, lack of due care and attention during
installation, and connector intermateability. Both canmanifest themselves as poor IL and/or RL performance.
When connectorized fiber optic jumpers from differing
manufacturers are used together as interconnects within asystem, the resulting IL and/or RL performance expectations
may not always be met. Theory suggests if all patchcords
from all manufacturers are compliant to industry standards,
then all are equal. This is not always the case. Specifications
are not finite and have defined tolerances, and suchtolerances however tight, will allow for inconsistencies, evenwith patchcords produced by the same manufacturer.
Overcoming such inconsistencies depend on more thanjust tight control of tolerances, they also depend on design
considerations to allow for the best intermateability possible.

4RANDOM MATING IL VS. IL BY MASTER JUMPERFor Insertion loss specification, the Telcordia GR-326
Core issue 4 states the IL should have the mean of 0.2dB
and the max of 0.4dB. In IEC Specification it states themean of 0.25dB and the max of 0.5dB. To adhere tothese specifications, the “best case” scenario of Master orReference patchcord and adaptor are used for testing in acontrolled environment.
It is a common misconception that the IL performanceobtained under such conditions truly replicate in the field
performance and, therefore, manufacturers often quote
the IL values. Although such values are a good referenceof performance under controlled conditions, they are notgood indicators of in the field performance, where genericpatchcords are mated together using generic adapters. In
such conditions, the majority of cases the IL will increase
and, in some cases, the increase can be significant.

Random Mating
Random Mating, a method of cross-mating patchcords
from differing manufacturers or manufactured batches
without the use of Master Patchcords or adapters, as
specified by IEC 61300-3-34 Attenuation of Random Mated
Connectors, and compliance with performance grades
outlined in IEC 61753-1, provides the best replication of IL
results seen in the field. Using this method, even a productcomplying with GR-326-COREs 0.2dB Mean IL and 0.4dB
Max IL against Master specification can have an IL in excessof 1.0dB.

Connector IL difference
By observing only the difference in IL measurements
tested against a Master Patchcord, it can be difficult todifferentiate good and bad quality connectors. However, it
is much easier to differentiate between the two using theRandom Mating method.
As an Example: The following graphs representing sample
batches 1 and 2, both of which comply with the GR326-CORE specification of Max IL 0.4dB against Master
Patchacord. However, when randomly mated the Max IL ofbatch 1 exceeds 1.0dB, whereas batch 2 is 0.25dB.

The IL distribution characteristics obtained from Random
Mating, illustrate the probability of obtaining a certain IL
level when connectors are randomly mated, providing aguarantee of manufacturer independent intermateability.
So it is imperative that patchcords perform in accordancewith these specifications to guarantee intermateability
with generic patchcords

Attenuation Grade

Grade A

Grade B

Grade C

Grade D

Attenuation Random Mated IEC 61300-3-34

Not Defined Yet
Not Defined Yet)0.12dB Mean IL)0.25dB Max IL for >97% of samples)0.25dB Mean IL)0.50dB Max IL for >97% of samples)0.50dB Mean IL)1.0dB Max IL for >97% of samples*IEC 61753-1 specifies four Random Mating IL performance
grades, of which grade A has yet to be defined.

RANDOM MATING IL VS. IL BY MASTER JUMPER

5Batch n°1 Low Cost Vendor, SC UPC Patchcord

Process Data
Sample Mean
Sample Number
StDev (Overall)
Max.IL

0.00

0.25

0.50

0.75

1.00

Process Data
0.12 dB
20
0.060 dB
0.3 dB

1.25

1.50

Sample Mean
Sample Number
StDev (Overall)
Max.IL

0.00

0.25

0.50

0.75

1.00

0.34 dB
360
0.292 dB
1.64 dB

1.25

1.50

IL measured by Random Mating
Exceed IEC Random Mating Grade D

IL measured against Master Patchcord
Meets GR-326 Max IL 0.4dB

Batch n°2 High Quality Vendor, using Senko Premium SM UPC Connector
Process Data
Sample Mean
Sample Number
StDev (Overall)
Max.IL

0.00

0.08

0.16

0.24

0.32

Process Data
0.08 dB
28
0.051 dB
0.2 dB

0.40

IL measured against Master Patchcord
Meets GR-326 Max IL 0.4dB

6RANDOM MATING IL VS. IL BY MASTER JUMPER

0.48

Sample Mean
Sample Number
StDev (Overall)
Max.IL

0.00

0.08

0.16

0.24

0.32

0.09 dB
360
0.060 dB
0.3 dB

0.40

IL measured by Random Mating
Exceed IEC Random Mating Grade B

0.48

Solution
SENKO has refined the designs of its Premium connector
range to give better performance on Random Mating.
A number of improvements have been made, including
but not limited to, better ferrule bore concentricity,
ferrule flange key re-design to improve Key Error, andtherefore, Apex Offset repeatability and controlled
free-floating ferrule. This has enabled much improved
manufacturer independent IL results. The graphs
illustrate the performance difference between SENKO’sconnectors and that of High Quality and Low Cost
alternatives.

Insertion Loss data against MasterGR 326
Max IL(0.4dB)

IECMax IL(0.5dB)

120%Points where Max IL is reached for each connector brand

100%
80%
60%
40%
20%
0%

SENKO has categorized its connectors to reflect the IEC
Random Mating specified grades A*, B, and C, allowing
the end-user to make an informed decision whenselecting connectors, of how finished patchcords using
SENKO connectors will perform.

Random mating Insertion Loss
IEC
Grade A
(0.15dB)

IEC
Grade B
(0.25dB)

IEC
Grade C(0.50dB)

IEC
Grade D(1.0dB)

120%
Points where Max IL is reached for each connector brand

100%
80%
60%
40%
SENKO Low Loss

20%SENKO Premium
SENKO Standard

0%

High quality Competitor
Low quality Competitor

RANDOM MATING IL VS. IL BY MASTER JUMPER

7Conclusion
In the Random Mating tests conducted, performanceof SENKO’s new connectors exceeded the highest
requirements specified by both Telcordia GR-326-CORE
and IEC industry standards. Products from a High Quality
competitor only able to meet the IECs Grade C rating,comparable to that of SENKO’s standard connectors.
In comparison however, SENKO’s Premium connectorsdelivered outstanding Random Mating IL results.

RANDOM MATING IEC VALUE
IEC Random Mating Grade A
IEC Random Mating Grade B
IEC Random Mating Grade C

IEC Random Mating Grade D

The performance of SENKO’s Premium and Premium
Low Loss connectors was such, that they easily exceeded
IECs 61753-1 Grade B requirement. In fact, performanceof the Premium Low Loss connector could even meetthe projected Grade A requirement. Such conclusive
results highlight the effectiveness of the new designs,
and a guarantee of compliance with industry standards
for IL against Master Patchcord, Random Mating IL andrepeatability.

SENKO UPC Connector) 0.07dB Mean*) 0.15dB Max*) 0.12dB Mean) 0.25dB Max) 0.25dB Mean) 0.50dB Max) 0.50dB Mean) 1.00dB Max

SENKO APC Connector

Typical Competitor

Premium Low Loss SM UPC Connector
Premium Low Loss SM APC Connector
Premium SM UPC Connector
Premium SM APC Connector
Standard SM UPC Connector

Typical High Quality UPC Connector
Standard SM APC Connector
Low cost quality UPC Connector* Maximum IL, 97% to meet the specification.
* For Random Mating Grade A, specification is not determined yet. Above spec for grade A is a proposed spec.
* Insertion Loss are only guaranteed when product terminated with Senko’s recommended procedure.

8RANDOM MATING IL VS. IL BY MASTER JUMPER