IEC TR 62343-6-6:2011

IEC/TR 62343-6-6
®

Edition 1.0 2011-01
TECHNICAL
REPORT


Dynamic modules –
Part 6-6: Failure mode effect analysis for optical units of dynamic modules


IEC/TR 62343-6-6:2011(E)

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2011 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00

---------------------- Page: 2 ----------------------
IEC/TR 62343-6-6
®

Edition 1.0 2011-01
TECHNICAL
REPORT

Dynamic modules –
Part 6-6: Failure mode effect analysis for optical units of dynamic modules


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
T
ICS 33.180.20 ISBN 978-2-88912-327-8

® Registered trademark of the International Electrotechnical Commission

---------------------- Page: 3 ----------------------
– 2 – TR 62343-6-6 © IEC:2011(E)
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Consideration of types of dynamic modules . 6
4 Typical failure points . 6
5 Failure modes and known failure mechanisms . 6
Bibliography . 25

Table 1 – Categorization based on the structure and how to evaluate . 7
Table 2 – Failure mode and known failure mechanisms for the optical units of dynamic
devices . 8

---------------------- Page: 4 ----------------------
TR 62343-6-6 © IEC:2011(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

DYNAMIC MODULES –

Part 6-6: Failure mode effect analysis
for optical units of dynamic modules


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of 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, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. 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".
IEC 62343-6-6, which is a technical report, has been prepared by subcommittee 86C: Fibre
optic systems and active devices, of IEC technical committee 86: Fibre optics.

---------------------- Page: 5 ----------------------
– 4 – TR 62343-6-6 © IEC:2011(E)
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
86C/944/DTR 86C/959/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 62343 series, published under the general title Dynamic modules, can
be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. 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.

---------------------- Page: 6 ----------------------
TR 62343-6-6 © IEC:2011(E) – 5 –
DYNAMIC MODULES –

Part 6-6: Failure mode effect analysis
for optical units of dynamic modules



1 Scope
This part of IEC 62343, which is a technical report, describes failure mode effect analysis
(FMEA) for optical units of dynamic modules. FMEA is one of the effective and useful analysis
methods to determine the reliability evaluation test items and conditions which are defined in
future reliability qualification documents. In order to estimate the lifetime for a module, there
is a typical procedure. The first step is to identify the dominant failure modes. The second
step is to determine the acceleration tests according to these failure modes. The third step is
to carry out the test. The fourth step is to estimate the acceleration factors. Finally, the fifth
step is to calculate the lifetime of the dynamic module. The IEC 61300-2 series defines
environment and mechanical tests. This technical report describes the dominant failure mode
for dynamic modules and relevant tests from the IEC 61300-2 series.
2 Normative references
The following reference documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 61300-2-1, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 2-1: Tests – Vibration (sinusoidal)
IEC 61300-2-4, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 2-4: Tests – Fibre/cable retention
IEC 61300-2-9, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 2-9: Tests – Shock
IEC 61300-2-17, Fibre optic interconnecting devices and passive components – Basic test
and measurement procedures – Part 2-17: Tests – Cold
IEC 61300-2-18, Fibre optic interconnecting devices and passive components – Basic test
and measurement procedures – Part 2-18: Tests – Dry heat – High temperature endurance
IEC 61300-2-19, Fibre optic interconnecting devices and passive components – Basic test
and measurement procedures – Part 2-19: Tests – Damp heat (steady state)
IEC 61300-2-22, Fibre optic interconnecting devices and passive components – Basic test
and measurement procedures – Part 2-22: Tests – Change of temperature
IEC 61300-2-44, Fibre optic interconnecting devices and passive components – Basic test
and measurement procedures – Part 2-44: Tests – Flexing of the strain relief of fibre optic
devices
IEC 62005-3, Reliability of fibre optic interconnecting devices and passive components –
Part 3: Relevant tests for evaluating failure modes and failure mechanisms for passive
components

---------------------- Page: 7 ----------------------
– 6 – TR 62343-6-6 © IEC:2011(E)
3 Consideration of types of dynamic modules
There are many types of dynamic modules: dynamic channel equalizer, tuneable optical
chromatic dispersion compensator, dynamic gain tilt equalizer, wavelength selective switch,
wavelength blocker, optical performance monitor, optical switch, and so on. The main feature
of dynamic modules is to control their performances during operation. In order to achieve their
features, many kinds of control mechanisms are used for dynamic modules; MEMS (micro
electro mechanical system), stepping motor, electromagnet, thermo optics, magnet optics,
electro optics, LCD (liquid crystal devices), and so on.
Table 1 shows the first guidance of categorization of dynamic modules to consider how to
evaluate. Dynamic modules without an electrical circuit board can be considered similar to
passive optical components for purposes of evaluation. On the other hand, for dynamic
modules with a control circuit board, it is necessary to give special consideration. There are
mainly two types of internal design for dynamic modules: those for which it is easy to divide
the constituting parts to consider their reliability, and those which it is not easy to divide. It is
necessary to consider how to evaluate according to these structures.
NOTE This technical report describes FMEA only for optical units for dynamic modules. It is necessary to
evaluate whole dynamic modules including control circuit boards and firmware if used.
4 Typical failure points
In addition to control circuit boards and control of moving parts, a typical optical unit for a
dynamic module consists of the following parts: optical element, outer package, fibre pigtails,
optical semiconductor chips, and joint points of these elements. These elements have their
own failure mode; for example, break for pigtails, displacement for joint points, and so on.
Moreover, these elements may have their acceleration factor of degradation; for example,
joint points fixed by adhesive are generally weak against high humidity, and so on. This
failure mode analysis can be referred to FMEA for passive optical components (refer to
IEC 62005-3).
There are special considerations for dynamic modules. The following are some examples.
When a hermetic sealing structure is used, the damp heat test may be omitted because it can
generally prevent humidity from entering the package. When using MEMS, operating shock
and vibration tests are necessary because MEMS are sensitive to mechanical shock and
vibration. When temperature control is used, the temperature cycling test is recommended
because temperature control functions generally produce thermal stress. The temperature
cycling test can accelerate thermal stress.
5 Failure modes and known failure mechanisms
For some dynamic modules, failure mode and effect analysis (FMEA) was carried out. Table 2
shows known failure mechanisms, failure effects, failure modes, relevant tests and IEC test
document numbers for dynamic modules. If new technology and new dynamic modules
become commercially available, they will be added to Table 2 in later revisions. Relevant
tests are listed with the failure effect and the dominant failure mechanism. As other relevant
tests or methods of failure mode excitation become known, these will also be added.

---------------------- Page: 8 ----------------------
TR 62343-6-6 © IEC:2011(E) – 7 –
Table 1 – Categorization based on the structure and how to evaluate
Electrical circuits How to evaluate Examples
Without
VOA, 1x2/2x2 optical switch,
electrical N.A. As optical component
DGTE
circuits
As optical and electrical units VOA, VOA-MUX, DCDC, DCE,
Easy to divide optical and
individually, and as integrated dynamic Matrix switch, channel monitor,
With
electrical unit
module performance monitor
electrical
circuit
Difficult to divide optical To evaluate as integrated dynamic Wavelength blocker, wavelength
and electrical unit module selectable switch
NOTE 1 Optical active and passive components should comply to the reliability qualification requirement defined in the
IEC 62572 series for active components and IEC 62009-9 series for passive optical components, respectively. In cases
in which it is difficult to divide optical and electrical units, integrated modules should be tested.
NOTE 2 Electrical circuit boards should be qualified individually. The following standard series are useful references for
the quality of electrical circuit boards: IEC 61188, IEC 61189, IEC 61190, and IEC 61191.
NOTE 3 Three pieces should be tested.

---------------------- Page: 9 ----------------------
– 8 – TR 62343-6-6 © IEC:2011(E)

Table 2 – Failure mode and known failure mechanisms for the optical units of dynamic devices
Constitution Known failure Degradation acceleration IEC
Dynamic devices Failure modes Relevant tests
parts mechanisms factors references
Uncontrollable Mechanical stress Shock (storage) 61300-2-9
Variable MEMS type MEMS Stacking the moving part
Vibration (storage) 61300-2-1
optical
Excess driving power Maximum absolute rating Under study
attenuators
test (electrical)
On/off driving test Under study
Insertion loss increase Mechanical stress Shock (storage) 61300-2-9
Distortion of hinge/mirror
Attenuation change Vibration (storage) 61300-2-1

Return loss decrease Thermal stress Shock and vibration Under study
Dynamic range of attenuation (operating)
decrease Change of temperature 61300-2-22
PDL increase Excess driving power Maximum absolute rating Under study
WDL increase test
On/off driving test Under study
Insertion loss increase High humidity (non- Damp heat
Reflectance of mirror 61300-2-19
Attenuation change hermetic sealed)
changing
Return loss decrease
PDL increase
WDL increase
Insertion loss increase Thermal stress Change of temperature 61300-2-22
Collimator
Dislocation of fixing
Attenuation change High temperature 61300-2-18
points of optical parts

Dynamic range of attenuation High humidity (non- Damp heat 61300-2-19
decrease hermetic sealed and using
PDL increase adhesive)
WDL increase Mechanical stress Shock (storage) 61300-2-9
Vibration (storage) 61300-2-1
Insertion loss increase
Pigtail Fibre broken, micro-
Mechanical stress for Fibre cable retention 61300-2-4
No operation
bending
pigtail
Optical fibre cable flexing 61300-2-44
Insertion loss increase Thermal stress Change of temperature 61300-2-22
Liquid LCD Degradation of LCD
Attenuation change High temperature 61300-2-18
crystal type
Return loss decrease High humidity (non- Damp heat 61300-2-19
Dynamic range of attenuation hermetic sealed)
decrease Mechanical stress Shock (storage) 61300-2-9
PDL increase Vibration (storage) 61300-2-1
WDL increase
Uncontrollable Excess driving power Maximum absolute rating Under study
Electrical polarization of
test
LCD
On/off driving test Under study
Uncontrollable Low temperature Cold 61300-2-17
Freezing of LCD
Same as MEMS type
Collimator
Same as MEMS type
Pigtail

---------------------- Page: 10 ----------------------
TR 62343-6-6 © IEC:2011(E) – 9 –

Table 2 (continued)
Constitution Known failure Degradation acceleration IEC
Dynamic devices Failure modes Relevant tests
parts mechanisms factors references
Insertion loss increase Change of temperature 61300-2-22
Variable Magnet Magnet optic part Dislocation of magnet, Thermal stress
Attenuation change High temperature 61300-2-18
optical optic type Faraday rotator and
High humidity (non-
Return loss decrease Damp heat 61300-2-19
attenuators birefringent crystal
hermetic sealed and using
Dynamic range of attenuation
adhesive)
decrease
PDL increase Mechanical stress Shock (storage) 61300-2-9
WDL increase Vibration (storage) 61300-2-1

Collimator
Same as MEMS type
Pigtail
Uncontrollable Mechanical stress Shock (storage) 61300-2-9
Mechanical Moving part Stacking the moving part
Vibration (storage) 61300-2-1
type
High humidity (non- Damp heat  61300-2-19

hermetic)  Under study
Excess driving power Maximum absolute rating

test (electrical) Under study

On/off driving test

Driving power increase Shock (storage) 61300-2-9
Degradation of moving Mechanical stress
Vibration (storage) 61300-2-1
part


Shock and vibration Under study

(operating)
Thermal stress
Change of temperature 61300-2-22

Excess driving power
Maximum absolute rating Under study

test Under study
On/off driving test
High humidity (non-
Damp heat 61300-2-19
hermetic sealed)

Insertion loss increase Mechanical stress Shock (storage) 61300-2-9
Distortion of mirror
Return loss decrease Vibration (storage) 61300-2-1

Crosstalk increase Thermal stress Change of temperature 61300-2-22
PDL increase Maximum absolute rating Under study
Excess driving power test
On/off driving test Under study
Insertion loss increase High humidity (non- Damp heat
Reflectance of mirror 61300-2-19
Attenuation change hermetic sealed)
changing
Return loss decrease
PDL increase
WDL increase
Same as MEMS type
Collimator
Same as MEMS type
Pigtail

---------------------- Page: 11 ----------------------
– 10 – TR 62343-6-6 © IEC:2011(E)

Table 2 (continued)
Constitution Known failure Degradation acceleration IEC
Dynamic devices Failure modes Relevant tests
parts mechanisms factors references
Insertion loss increase Change of temperature 61300-2-22
Variable Planar Waveguide Refractive index changing Thermal stress
Attenuation change High temperature 61300-2-18
optical waveguide
 High humidity (non-
Return loss decrease Damp heat
...