IEC TR 62343-6-6:2017

IEC TR 62343-6-6 ®
Edition 2.0 2017-01
TECHNICAL
REPORT
Dynamic modules –
Part 6-6: Design guide – Failure mode effect analysis for optical units of dynamic
modules
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IEC TR 62343-6-6 ®
Edition 2.0 2017-01
TECHNICAL
REPORT
Dynamic modules –
Part 6-6: Design guide – Failure mode effect analysis for optical units of dynamic

modules
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.20 ISBN 978-2-8322-3719-9

– 2 – IEC TR 62343-6-6:2017 © IEC 2017
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Consideration of types of dynamic modules . 6
5 Typical failure points. 6
6 Failure modes and known failure mechanisms . 7
Bibliography . 29

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

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DYNAMIC MODULES –
Part 6-6: Design guide – 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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
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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.
This second edition cancels and replaces the first edition published in 2011. It constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of the LCOS based and the DLP based wavelength selective switch (WSS);

– 4 – IEC TR 62343-6-6:2017 © IEC 2017
b) addition of the multicast optical switch module (MCOS).
The text of this technical report is based on the following documents:
DTR Report on voting
86C/1396/DTR 86C/1421/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 in the 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.

DYNAMIC MODULES –
Part 6-6: Design guide – 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 that 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.
IEC 61300-2 (all parts) defines environment and mechanical tests. This Technical Report
describes the dominant failure mode for dynamic modules and relevant tests from
IEC 61300-2 (all parts).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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

– 6 – IEC TR 62343-6-6:2017 © IEC 2017
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
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 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; micro electro
mechanical system (MEMS), stepping motor, electromagnet, thermo optics, magnet optics,
electro optics, liquid crystal device (LCD), and so on.
Table 1 shows the first guidance of categorization of dynamic modules and their mode of
evaluation. 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 the reliability, and those for which it is not easy to divide. It
is necessary to consider how to evaluate according to these structures.
This document 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.
5 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 and displacement for joint points. Moreover,
these elements may have their acceleration factor of degradation; for example, joint points
fixed by adhesive are generally weak against high humidity. 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 using MEMS, operating shock and vibration test 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.

6 Failure modes and known failure mechanisms
For some dynamic modules, FMEA is 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 of this document. 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.
Table 1 – Categorization based on the structure and mode of evaluation
Electrical circuits How to evaluate Examples
Without N.A. As optical component VOA, 1x2/2x2 optical switch, DGTE
electrical
circuits
With Easy to divide optical As optical and electrical units VOA, VOA-MUX, TDC (DCDC),
electrical and electrical unit individually, and as integrated DCE, matrix switch, channel
circuit dynamic module monitor, performance monitor
Difficult to divide To evaluate as integrated dynamic Wavelength blocker (WB),
optical and electrical module Wavelength selective switch (WSS)
unit
Optical active and passive components should comply with the reliability qualification requirement defined in
IEC 62572 (all parts) for active components and IEC 62005-9 (all parts) for passive optical components,
respectively. In cases in which it is difficult to divide optical and electrical units, integrated modules should be
tested.
Electrical circuit boards should be qualified individually. The following standards series are useful references for
the quality of electrical circuit boards: IEC 61188 (all parts), IEC 61189 (all parts), IEC 61190 (all parts), and
IEC 61191 (all parts).
Three pieces should be tested.

– 8 – IEC TR 62343-6-6:2017 © IEC 2017

Table 2 – Failure mode and known failure mechanisms for the optical units of dynamic devices
Dynamic devices Constitution Known failure Failure modes Degradation acceleration Relevant tests IEC references
parts mechanisms factors
Variable optical MEMS type MEMS Stacking the moving part Uncontrollable Mechanical stress Shock (storage) IEC 61300-2-9
attenuators
Excess driving power Vibration (storage) IEC 61300-2-1
Maximum absolute rating Under study
test (electrical)
Under study
On/off driving test
Distortion of hinge/mirror Insertion loss increase Mechanical stress Shock (storage) IEC 61300-2-9
Attenuation change Thermal stress Vibration (storage) IEC 61300-2-1
Return loss decrease Excess driving power Shock and vibration Under study
(operating)
Dynamic range of IEC 61300-2-22
attenuation decrease Change of temperature
Under study
PDL increase Maximum absolute rating
Under study
test
WDL increase
On/off driving test
Reflectance of mirror Insertion loss increase High humidity (non-hermetic Damp heat IEC 61300-2-19
changing sealed)
Attenuation change
Return loss decrease
PDL increase
WDL increase
Collimator Dislocation of fixing points Insertion loss increase Thermal stress Change of temperature IEC 61300-2-22
of optical parts Attenuation change
High humidity (non-hermetic High temperature IEC 61300-2-18
Dynamic range of sealed and using adhesive)
Damp heat IEC 61300-2-19
attenuation decrease
Mechanical stress
Shock (storage) IEC 61300-2-9
PDL increase
Vibration (storage) IEC 61300-2-1
WDL increase
Pigtail Fibre broken, micro- Insertion loss increase Mechanical stress for pigtail Fibre cable retention IEC 61300-2-4
bending
No operation Optical fibre cable IEC 61300-2-44
flexing
Dynamic devices Constitution Known failure Failure modes Degradation acceleration Relevant tests IEC references
parts mechanisms factors
Liquid LCD Degradation of LCD Insertion loss increase Thermal stress Change of temperature IEC 61300-2-22
crystal type
Attenuation change High humidity (non-hermetic High temperature
IEC 61300-2-18
sealed)
Return loss decrease Damp heat IEC 61300-2-19
Mechanical stress
Dynamic range of Shock (storage) IEC 61300-2-9
attenuation decrease
Vibration (storage) IEC 61300-2-1
PDL increase
WDL increase
Electrical polarization of Uncontrollable Excess driving power Maximum absolute rating Under study
LCD test
Under study
On/off driving test
Freezing of LCD Uncontrollable Low temperature Cold IEC 61300-2-17
Collimator Same as MEMS type
Pigtail Same as MEMS type
Magnet optic Magnet optic Dislocation of magnet, Insertion loss increase Thermal stress Change of temperature IEC 61300-2-22
type part Faraday rotator and
Attenuation change High humidity (non-hermetic High temperature IEC 61300-2-18
birefringent crystal
sealed and using adhesive)
Return loss decrease Damp heat IEC 61300-2-19
Mechanical stress
Dynamic range of Shock (storage) IEC 61300-2-9
attenuation decrease
Vibration (storage) IEC 61300-2-1
PDL increase
WDL increase
Collimator Same as MEMS type
Pigtail Same as MEMS type
Mechanical Moving part Stacking the moving part Uncontrollable Mechanical stress Shock (storage) IEC 61300-2-9
type
High humidity (non-hermetic) Vibration (storage) IEC 61300-2-1
Excess driving power Damp heat IEC 61300-2-19
Maximum absolute rating Under study
test (electrical)
Under study
On/off driving test
– 10 – IEC TR 62343-6-6:2017 © IEC 2017

Dynamic devices Constitution Known failure Failure modes Degradation acceleration Relevant tests IEC references
parts mechanisms factors
Degradation of moving part Driving power increase Mechanical stress Shock (storage) IEC 61300-2-9
Thermal stress Vibration (storage) IEC 61300-2-1
Excess driving power Shock and vibration Under study
(operating)
High humidity (non-hermetic IEC 61300-2-22
sealed) Change of temperature
Under study
Maximum absolute rating
Under study
test
IEC 61300-2-19
On/off driving test
Damp heat
Distortion of mirror Insertion loss increase Mechanical stress Shock (storage) IEC 61300-2-9
Return loss decrease Thermal stress Vibration (storage) IEC 61300-2-1
Crosstalk increase Excess driving power Change of temperature IEC 61300-2-22
PDL increase Maximum absolute rating Under study
test
Under study
On/off driving test
Reflectance of mirror Insertion loss increase High humidity (non-hermetic Damp heat IEC 61300-2-19
changing sealed)
Attenuation change
Return loss decrease
PDL increase
WDL increase
Collimator Same as MEMS type
Pigtail Same as MEMS type
Planar Waveguide Refractive index changing Insertion loss increase Thermal stress Change of temperature IEC 61300-2-22
waveguide Attenuation change
High humidity (non-hermetic High temperature IEC 61300-2-18
type (thermal
Return loss decrease sealed and using adhesive)
optic effect)
Damp heat IEC 61300-2-19
Dynamic range of Mechanical stress
Shock (storage) IEC 61300-2-9
attenuation decrease
Vibration (storage) IEC 61300-2-1
PDL increase
Dynamic devices Constitution Known failure Failure modes Degradation acceleration Relevant tests IEC references
parts mechanisms factors
Electrode degradation Dynamic range of High humidity (non-hermetic Damp heat IEC 61300-2-19
attenuation decrease sealed and using adhesive)
Maximum absolute rating Under study
Excess driving power test
Under study
Diving test
Fixing point Dislocation by the Insertion loss increase Thermal stress Change of temperature IEC 61300-2-22
between degradation of adhesive
High humidity (non-hermetic Damp heat IEC 61300-2-19
waveguide
sealed and using adhesive)
and fibres
Pigtail Same as MEMS type
Optical Mechanical Moving part Stacking the moving part Uncontrollable Same as VOA mechanical type
switches type
Degradation of moving part Driving power increase Same as VOA mechanical type
Switching time increase
Distortion of mirror Insertion loss increase Same as VOA mechanical type
Return loss decrease
Crosstalk increase
PDL increase
Reflectance of mirror Insertion loss increase Same as VOA mechanical type
changing
Return loss decrease
PDL increase
WDL increase
Collimator Same as VOA MEMS type Insertion loss increase Same as VOA mechanical type
Crosstalk increase
PDL increase
WDL increase
Pigtail Same as VOA MEMS type
Planar Waveguide Refract
...