IEC TR 61282-3:2002

RAPPORT CEI
TECHNIQUE IEC
TR 61282-3
TECHNICAL
REPORT
First edition
2002-08
Fibre optic communication system
design guides –
Part 3:
Calculation of polarization mode dispersion
Guides de conception des systèmes
de communication à fibres optiques –
Partie 3:
Calcul de la dispersion en mode de polarisation

Numéro de référence
Reference number
CEI/IEC/TR 61282-3:2002
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

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RAPPORT CEI
TECHNIQUE IEC
TR 61282-3
TECHNICAL
REPORT
First edition
2002-08
Fibre optic communication system
design guides –
Part 3:
Calculation of polarization mode dispersion
Guides de conception des systèmes
de communication à fibres optiques –
Partie 3:
Calcul de la dispersion en mode de polarisation

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– 2 – TR 61282-3  IEC:2002(E)

CONTENTS
FOREWORD . 3

INTRODUCTION .5

1 Scope and object . 6

2 Basic design models for total system PMD performance . 6

2.1 Notation. 6

2.2 Calculation of system PMD . 7

2.2.1 System maximum PMD . 8

2.2.2 Calculation of system maximum DGD. 8
3 Calculation of cabled fibre PMD.10
3.1 Method 1: Calculating PMD , the PMD link design value.11
Q
3.1.1 Determining the probability distribution of the link PMD coefficients .11
3.1.2 Determining the value of PMD .13
Q
3.2 Method 2: Calculating the probability of exceeding DGDmax.15
3.2.1 Combining link and Maxwell variations.16
3.2.2 Convolution: Theory of method 2 .17
3.3 Equivalence of methods .18
3.3.1 Equivalence of the default specifications .19
3.3.2 Discussion regarding the basis of the default specifications
for method 2 .20
3.3.3 Calculation of the parameters of figure 4 .20
4 Calculation of optical component PMD.20
4.1 Calculation for random components .21
4.2 Calculation for deterministic components .21
4.2.1 Worse case calculation .21
4.2.2 Calculation for embedded deterministic components.22
5 Summary of acronyms and symbols .22
Annex A (informative) PMD concatenation fundamentals.24
A.1 Definitions .24
A.2 Concatenation – General .25
A.3 Application to random elements .25

A.4 Application to deterministic elements .26
Annex B (informative) Combining Maxwell extrema from two populations .28
B.1 Maxwell distribution definitions.28
B.2 Convolution definition .29
B.3 Convolution of optical fibre cable and random components .29
B.4 Evaluation of the double convolution .30
Annex C (informative) Worked example.32
Annex D (informative) Relationship of probability to system performance .33
Annex E (informative) Concatenation experiment.34
Bibliography .36

TR 61282-3  IEC:2002(E) – 3 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
FIBRE OPTIC COMMUNICATION SYSTEM DESIGN GUIDES –

Part 3: Calculation of polarization mode dispersion

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
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for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this technical report may be the subject of
patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example “state of the art”.
Technical reports do not necessarily have to be reviewed until the data they provide are
considered to be no longer valid or useful by the maintenance team.
IEC 61282-3, which is a technical report, has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.

The text of this technical report is based on the following documents:
Enquiry draft Report on voting
86C/296/DTR 86C/346/RVC
Full information on the voting for the approval of this technical report can be found in the report
on voting indicated in the above table.
Annexes A, B, C, D and E are for information only.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
This document, which is purely informative, is not to be regarded as an International Standard.

– 4 – TR 61282-3  IEC:2002(E)

The committee has decided that the contents of this publication will remain unchanged until

2006 At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or

• amended.
A bilingual version of this publication may be issued at a later date.

TR 61282-3  IEC:2002(E) – 5 –

INTRODUCTION
Polarization mode dispersion (PMD) is usually described in terms of a differential group delay

(DGD), which is the time difference between the principal states of polarization of an optical

signal at a particular wavelength and time. PMD in cabled fibres and optical components

causes an optical pulse to spread in the time domain, which may impair the performance of

a fibre optic telecommunication system, as defined in IEC 61281-1.

– 6 – TR 61282-3  IEC:2002(E)

FIBRE OPTIC COMMUNICATION SYSTEM DESIGN GUIDES –

Part 3: Calculation of polarization mode dispersion

1 Scope
The purpose of this technical report is to provide guidelines for the calculation of polarization

mode dispersion (PMD) in fibre optic systems to accommodate the statistical variation of PMD
and differential group delay (DGD) in optical fibre cables and components.
This guideline describes methods for calculating PMD due to optical fibre cables and optical
components in an optical link. Example calculations are given to illustrate the methods for
calculating total optical link PMD from typical cable and optical component data. The
calculations include the statistics of concatenating individual optical fibre cables drawn from
a specified distribution. The calculations assume that all components have PMD equal to the
maximum specified value.
NOTE The statistical specification of the distribution of the PMD of optical fibre cables is a current work item to
amend IEC 60794-3, in SC86A/WG3 [2] . The agreements following the last ballot (86A/501/CD) are aligned with
the methods given in this technical report.
The calculations described cover first order PMD only. This study of PMD continues to evolve,
therefore the material in this technical report may be modified in the future. The following
subject areas are currently beyond the scope of this technical report, but remain under study:
– calculation of second and higher order PMD;
– accommodation of components with polarization dependent loss (PDL) – if it is assumed
that PDL is negligible in optical fibre cables;
– system impairments (power penalty) due to PMD;
– interaction with chromatic dispersion and other nonlinear effects.
Measurement of PMD is beyond the scope of this technical report. Guidelines on the
measurement of PMD of optical fibre and cable are given in IEC 61941. The measurement of
optical amplifier PMD will be documented in IEC 61290-11-1 . The measurement of component
PMD will be documented in IE
...