IEC 62496-2-2:2011

Optical circuit boards - Part 2-2: Measurements - Dimensions of optical circuit boards

IEC 62496-2-2:2011 specifies the measurement procedures for dimensions related to interface information of optical circuit boards (OCB), defined in IEC 62496-4.

Cartes à circuits optiques - Partie 2-2: Mesures - Dimensions des cartes à circuits optiques

La CEI 62496-2-2:2011 spécifie les méthodes de mesure pour les dimensions liées aux informations d'interface des cartes à circuits optiques (OCB), définies dans la CEI 62496-4.

General Information

• Status: Published
• Publication Date: 26-Jan-2011
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.180.01 - Fibre optic systems in general
• Technical Committee: TC 86 - Fibre optics
• Drafting Committee: JWG 9 - TC 86/JWG 9
• Current Stage: PPUB - Publication issued
• Start Date: 31-Jan-2011
• Completion Date: 27-Jan-2011

Overview

IEC 62496-2-2:2011 is an international standard published by the International Electrotechnical Commission (IEC) that specifies measurement procedures for determining the dimensions of optical circuit boards (OCBs). As a part of the IEC 62496 series, this document focuses specifically on the dimensional aspects of OCBs, critical for ensuring compatibility and performance at optical interface points defined in IEC 62496-4.

Optical circuit boards are essential components in integrated photonic systems, enabling optical signal transmission and switching. Accurate measurement of their dimensions guarantees interoperability and functional integrity across diverse applications such as telecommunications, data centers, and sensor technology.

Key Topics

• Measurement Procedures: The standard defines detailed methodologies for measuring critical dimensions of optical circuit boards, including:

  • Core shape measurement through near-field pattern observation.
  • Coordinates of input/output (I/O) ports for both end face and surface I/O types.
  • Outer shape verification using optical observation systems or reference dimensional drawings.
  • Misalignment angles of I/O ports ensuring precise optical coupling.
  • Mirror angle assessment for accurate reflection and routing of optical signals.
  • Hole measurements using optical or laser scanning technologies.

• Equipment and Methods: IEC 62496-2-2 prescribes the use of sophisticated observation systems such as optical microscopes with high-resolution objectives, confocal microscopes, laser scanners, and optical position adjusting systems. These tools provide reproducible and accurate measurements under standardized environmental conditions aligned with IEC 60068-1.

• Measurement Conditions: All dimensional measurements are recommended to be performed under controlled environmental conditions, ensuring consistency and reliability of data. The standard allows alternative conditions when necessary, provided measurement accuracy is maintained.

• Terminology and Normative References: The document clarifies key terms, including "optical position adjusting system" for alignment and "dimensional drawing" for body shape accuracy. It also references related standards such as IEC 62496-4 for interface standards and IEC 60793-1-45 for mode field diameter measurement.

Applications

IEC 62496-2-2:2011 provides practical measurement guidance to manufacturers, test laboratories, and quality assurance teams involved in the production and verification of optical circuit boards used in:

• Telecommunication Networks: Ensuring precise alignment and interconnection in optical switching modules and transceiver systems.
• Data Centers: Supporting high-speed optical interconnection boards to manage increasing data throughput demands.
• Integrated Photonic Devices: Facilitating precise dimensional control in photonic integrated circuits where optical signal integrity depends on accurate component geometry.
• Sensor Systems: Enabling reliable optical signal pathways in sensing applications where dimensional accuracy impacts performance.
• Research and Development: Offering standardized measurement procedures essential for the design validation and development of new optical circuit board technologies.

Implementing the measurement procedures improves optical coupling efficiency, reduces signal loss, and enhances product interoperability in a global supply chain.

Related Standards

• IEC 62496-4: Defines the interface standards and general guidance for optical circuit boards, complementing the dimensional measurement procedures in IEC 62496-2-2.
• IEC 60068-1: Provides environmental testing guidelines to ensure reliable measurement conditions.
• IEC 60793-1-45: Specifies the measurement methods for mode field diameter, closely related to core shape characterization in OCBs.
• IEC 62496-2-1: Covers measurements related to optical attenuation and isolation of optical circuit boards, complementing dimensional analysis.
• ISO 10360-2: Details acceptance tests for coordinate measuring machines used in linear dimension measurements, applicable in OCB dimensional inspection.

---

Keywords: IEC 62496-2-2, optical circuit boards, OCB dimensional measurement, optical interface standards, optical core shape, I/O port coordinates, optical position adjusting system, optical coupling, confocal microscope, laser scanning, IEC standards optical technology.

Standards Content (Sample)

IEC 62496-2-2 ®
Edition 1.0 2011-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical circuit boards –
Part 2-2: Measurements – Dimensions of optical circuit boards

Cartes à circuits optiques –
Partie 2-2: Mesures – Dimensions des cartes à circuits optiques

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IEC 62496-2-2 ®
Edition 1.0 2011-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical circuit boards –
Part 2-2: Measurements – Dimensions of optical circuit boards

Cartes à circuits optiques –
Partie 2-2: Mesures – Dimensions des cartes à circuits optiques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 33.180.01 ISBN 978-2-88912-316-2
– 2 – 62496-2-2  IEC:2011
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Measurement condition . 7
5 Objects to be measured and their procedures . 7
6 Measurement procedures for dimensions . 7
6.1 Core shape . 7
6.1.1 Measuring equipment . 7
6.1.2 Procedure . 9
6.2 Coordinates of I/O ports . 9
6.2.1 Measurement procedure for end face I/O type OCB . 9
6.2.2 Measurement procedure for surface I/O port type OCB . 11
6.3 Outer shape of optical circuit board . 14
6.3.1 Method 1 (reference) – Use of observation system . 14
6.3.2 Method 2 (alternative) – Use of dimensional drawing . 15
6.4 Misalignment angle of I/O ports . 16
6.4.1 Observation of cross section . 16
6.5 Mirror angle . 19
6.5.1 Method 1 (reference) – Use of observation system . 19
6.5.2 Method 2 (alternative) – Use of confocal microscope . 20
6.6 Hole . 21
6.6.1 Method 1 (reference) – Use of observation system . 21
6.6.2 Method 2 (alternative) – Use of laser scanning . 22
Annex A (informative) Pattern pitch . 24
Bibliography . 27

Figure 1 – Example of measuring equipment capable of observing core shape . 8
Figure 2 – Example of sample set-up for observation of core shape (end face I/O
type OCB or a sliced sample). 8
Figure 3 – Example of sample set-up using a halogen lamp house with light-guide
fibre for observation of core shape (surface I/O type OCB) . 9
Figure 4 – Example of optical position adjustment system for end face I/O type OCB . 10
Figure 5 – Example of optical position adjustment system for surface I/O type OCB . 13
Figure 6 – Example of verification with a dimensional drawing for a fibre flexible
OCB . 16
Figure 7 – Misalignment angle of I/O ports in end face I/O type OCB . 17
Figure 8 – Misalignment angle of I/O ports in surface I/O type OCB . 17
Figure 9 – Parameters for misalignment angle in end face I/O type OCB . 18
Figure 10 – Parameters for misalignment angle in surface I/O type OCB . 18
Figure 11 – Schematic diagram of the mirror angle measurement using a confocal
microscope . 21
Figure 12 – Example of the profile at a mirror portion using a confocal microscope . 21
Figure A.1 – Pattern pitch and objects of measurement (an example of single layer) . 24
Figure A.2 – Pattern pitch and objects of measurement (an example of multi-layer) . 25

62496-2-2  IEC:2011 – 3 –
Table 1 – Objects to be measured and their methods . 7

– 4 – 62496-2-2  IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL CIRCUIT BOARDS –
Part 2-2: Measurements –
Dimensions of optical circuit boards

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization
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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.
International Standard IEC 62496-2-2 has been prepared by IEC technical committee 86:
Fibre optics.
The text of this standard is based on the following documents:
FDIS Report on voting
86/378/FDIS 86/385/RVD
Full information on the voting for the approval of this standard 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 the IEC 62496 series, published under the general title Optical circuit
boards, can be found on the IEC website.

62496-2-2  IEC:2011 – 5 –
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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – 62496-2-2  IEC:2011
OPTICAL CIRCUIT BOARDS –
Part 2-2: Measurements –
Dimensions of optical circuit boards

1 Scope
This part of IEC 62496 specifies the measurement procedures for dimensions related to
interface information of optical circuit boards (OCB), defined in IEC 62496-4.
2 Normative references
The following referenced 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 60068-1, Environmental testing – Part 1: General and guidance
IEC 60793-1-45, Optical fibres – Part 1-45: Measurement methods and test procedures –
Mode field diameter
IEC 61189-2, Test methods for electrical materials, printed boards and other
interconnection structures and assemblies – Part 2: Test methods for materials for
interconnection structures
IEC 62496-2-1, Optical circuit boards – Part 2-1: Measurements – Optical attenuation and
isolation
IEC 62496-4, Optical circuit boards – Part 4: Interface standards – General and guidance
ISO 10360-2, Geometrical product specifications (GPS) – Acceptance and reverification
tests for coordinate measuring machines (CMM) – Part 2: CMMs used for measuring linear
dimensions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
optical position adjusting system
consists of a light source, fibre position adjustment stage, OCB holder, input/output fibre
and a power meter. The optimum fibre launch position, at which the optical output power is
maximised, is determined through alignment of the input/output fibres to the OCB and
monitoring the output power from the OCB
3.2
dimensional drawing
illustration, including dashed lines, which defines classified OCB or OCB body shape
accuracy using the origin point or alignment mark as the standard point
___________
To be published.
62496-2-2  IEC:2011 – 7 –
4 Measurement condition
All the measurements are made under the conditions specified in IEC 60068-1, unless
otherwise specified. Measurements may be made under different conditions to the standard
conditions if the standard conditions are difficult to achieve, as long as the actual
measurement condition does not give rise to any doubt as to the result of the measurement.
5 Objects to be measured and their procedures
Objects to be measured as dimensions of OCB are stated in IEC 62496-4. The objects and
their methods are summarized in Table 1. This standard specifies mainly mechanical
procedures using observation systems for dimensions of OCBs.
Table 1 – Objects to be measured and their methods
Method 1
Method 2 (alternative)
(reference)
Optical
Observation Dimensional Confocal Laser
position
system drawing microscope scanning
adjustment
Core shape O
Coordinates of I/O
O O
port
Outer shape of
O O
OCB
Misalignment
O
angles of I/O
Mirror O  O
Hole O  O
6 Measurement procedures for dimensions
6.1 Core shape
6.1.1 Measuring equipment
6.1.1.1 General
The measuring equipment consists of observation, shape measuring and data processing
systems. The measurement system shall give reproducible results. An example of a total
measuring system is illustrated in Figure 1. Structural parameters for circlar core shape are
obtained by near field pattern observation of cross section specified in IEC 60793-1-45.
6.1.1.2 Observation system
The observation system detects a core shape by an optical microscope with resolution of
less than 1 % of designated dimension. It is necessary to select appropriate lighting,
magnification, detection system and fibre positioning system to obtain sufficient
measurement accuracy, but x10 to x80 for the object lens and x10 for the eyepiece seem
appropriate. A camera is also used for the observation of large core shape. An example of
sample set-up for the observation is illustrated in Figures 2 and 3. A light is launched in the
vicinity of one of I/O ports. The output light from the sample is detected from the other one
by the observation system. A movable stage or the observation system can have the
measuring function. The movable stage should be controllable in x, y and z axes and
vertical and horizontal rotations, independently.

– 8 – 62496-2-2  IEC:2011
6.1.1.3 Data processing system
The data processing system has the capability of analyzing image information taken from
the observation system and calculates structural parameters of core shape.

Observation
Observation
system
system
OCB
OCB
Data processing sytem
Data processing system
Movable stage with scale
Movable stage with scale IEC  001/11

Figure 1 – Example of measuring equipment capable of observing core shape

Observation by microscope
End face tyoe OCB
Light source
or
Sliced OCB
Exposure
Light-guide
(optional)
Movable stage
IEC  002/11
Figure 2 – Example of sample set-up for observation of core shape
(end face I/O type OCB or a sliced sample)

62496-2-2  IEC:2011 – 9 –
Electric circuit layer
Observation by
microscope
Light-guide
Output light from OCB
(optional)
Exposure
Light source
Surface I/O
type OCB
Mirror
Mirror
Waveguide layer
Movable stage
IEC  003/11
Figure 3 – Example of sample set-up using a halogen lamp house with light-guide
fibre for observation of core shape (surface I/O type OCB)
6.1.2 Procedure
a) Preparation
When the core shape which is not an I/O port is measured, an OCB is cut with a blade to a
smooth surface at a right angle to the core pattern. The OCB is set-up to observe I/O ports
or a sliced surface, as illustrated in Figures 2 and 3. The magnification of an optical
microscope is calibrated before measurement.
b) Measurement
Adjust the focus of the optical microscope at the position where the core shape can be
observed by moving the movable stage or the optical microscope. The core shape is
determined by processing of image information coming from the observation system. It is
possible to confirm the distance to the object under measurement if the optical microscope
has a distance measuring capability. The six structural parameters for a square core shape
are obtained by data analysis of the core shape according to definitions of their parameters
in IEC 62496-4.
6.2 Coordinates of I/O ports
6.2.1 Measurement procedure for end face I/O type OCB
6.2.1.1 Method 1 (reference) – Use of observation system
6.2.1.1.1 Measuring equipment
The measuring equipment stated in 6.1.1 shall be used.
6.2.1.1.2 Procedure
One example of measurement procedure is described below.
a) Preparation
The sample is fastened to the movable stage using a jig to attain flatness and to prevent it
from moving while measuring.
b) Measurement
– 10 – 62496-2-2  IEC:2011
Align the direction of the coordinate axis and that of the movement of the movable stage to
obtain horizontal reference. Move the microscope to the coordinate origin to define its
coordinate to origin point. The origin point should be selected to the centre of the origin
point structure for an external coordinate system, and to the core centre when the origin is
specified by a coordinate of a specific core centre for internal coordinate system. Then
measure the coordinates of the core centres as I/O ports. There are some cases where the
observation of the I/O ports by a microscope is difficult, especially for surface I/O type. A
light is launched to the opposite port of the object of the OCB, and the image of exiting light
is observed.
6.2.1.2 Method 2 (alternative) – Use of optical position adjusting system
6.2.1.2.1 Measuring equipment
An optical position adjusting system consists of a light source, automatic fibre position
adjustment stage, OCB holder, input/output fibre and a power meter. A schematic of the
system illustrated in Figure 4 is a typical example of measurement systems for optical
attenuation of an OCB stated in IEC 62496-2-1.

LiLiLight sght sght sourourourcecc ee
FiFiFbbibrerere ffofoorrr ou ou outputtputtput
OCB sample
OOCBCB s samamplplee
PPPowowowererer m m metereteete rr
Fibre for input
FiFibbrere foforr i inputnput
Control
ContrControlol
system
sysyststeemm
OCB holder
OOCBCB hol holderder
Fibre adjusting stage
FiFibbrere adjadjusustiting sng stagetage

IEC  004/11
Figure 4 – Example of optical position adjustment system for end face I/O type OCB
a) Light source
Prepare a light source as stated in IEC 62496-2-1.
b) Fibre position adjustment stage
Fibre position adjustment stage consists of a jig for fixing an input/output fibre near an OCB
and a movable stage. The movable stage should be controllable in x, y and z axes and
vertical and horizontal rotations, independently. The preferred resolutions of the
micromanipulators operated by stepping motors are ≤0.1 µm and ≤1.5 µm for the single
mode and the multimode measurements, respectively. The repeatablilty of measurement is
less than 1 % of designated dimension.

62496-2-2  IEC:2011 – 11 –
c) OCB holder
The OCB holder is to fix an OCB and should be provided with a rotation control stage for
alignment of coordinate axes.
d) Input/output fibres
Select appropriate optical fibres for introduction and detection of input into and output from,
respectively, I/O ports, according to IEC 62496-2-1. The input light should be stabilized in
its mode using a mode filter according to IEC 62496-2-1. It is recommended that the core
diameters and numerical aperture (NA) of input/output fibres are similar to those for optical
circuit of interest.
e) Power meter
Prepare a power meter according to IEC 62496-2-1. Measure the power of an optical output
and feed-back to the fibre position adjustment stage in order to obtain the position where
the maximum optical power output is available in a short time.
6.2.1.2.2 Procedure
a) Preparation
Preparation of measurement is as described in 6.2.1.1.
b) Measurement
1) Internal coordinate system
An OCB is placed on the OCB holder and input and output fibres are brought close
to the I/O port which is origin point. A light is launched in one port and detects from
the corresponding port by output fibre. Input fibre is moved in order to search the
position where the output power is the maximum value. Measure the coordinate of
input fibre as an origin point. Then input and output fibres are moved to I/O ports
which are to be measured. The position where the output power is maximum value
is obtained as coordinates in this way for other cores. These positions should be
calculated as the coordinate of I/O ports based on origin point measured in advance.
2) External coordinate system
The input fibre is moved to obtain the coordinate of externally formed origin point by
an observation system. Input and output fibres are brought close to the optical I/O
port of interest. A light is launched in one port and detects from the corresponding
port by output fibre. Input fibre is moved in order to search the position where the
output is the maximum. The position where the output power is maximum value is
obtained in this way for other cores. These positions should be calculated as the
coordinate of I/O ports based on externally formed origin point measured in
advance.
6.2.2 Measurement procedure for surface I/O port type OCB
6.2.2.1 Method 1 (reference) – Use of observation system
6.2.2.1.1 Equipment
Measuring equipment is illustrated in 6.2.1.1.

– 12 – 62496-2-2  IEC:2011
6.2.2.1.2 Procedure
a) Preparation
The magnification of the optical microscope to be used is calibrated in advance. The
sample is fastened to the measuring stage using a jig to attain flatness and to prevent it
from moving while measuring.
b) Measurement
Align the direction of the coordinate axis and that of the movement of the movable stage to
obtain horizontal reference. Move the microscope to the coordinate origin to define its
coordinate to origin point. The origin point should be selected to the centre of the origin
point structure for an external coordinate system, and to the core centre when the origin is
specified by a coordinate of a specific I/O port for an internal coordinate system. Measure
the coordinate of each I/O port. There are cases where the direct observation of the plane
by a microscope is difficult. A light may be launched in the port on the other side of the
board and the near field pattern of the exiting light may be observed.
6.2.2.2 Method 2 (alternative) – Use of optical position adjusting system
6.2.2.2.1 Equipment
An optical position adjusting system consists of a light source, automatic fibre position
adjustment stage, OCB holder, input/output fibre and a power meter. A schematic of the
system illustrated in Figure 5 is one of measurement systems for optical attenuation of an
OCB specified in IEC 62496-2-1.

62496-2-2  IEC:2011 – 13 –
Optical microscope
Control
system
Power
Optical
Fibre for output
Fibre for input
meter
source
Rotation
Rotation
z z
Rotation
Rotation
Rotation
Rotation
OCB
θ
x x
y y
・・・ Movable stage
Sensor for butting between Stage for OCB
fibre and OCB
IEC  005/11
Figure 5 – Example of optical position adjustment system for surface I/O type OCB
a) Light source
Prepare a light source as stated in IEC 62496-2-1.
b) Observation optics
The system can capture images of I/O ports, references of coordinate origin and the
direction of the axis and can display an image on a screen (not shown in Figure 5).
c) Movable stage
The movable stage should be controllable in x, y and z axes and vertical and horizontal
rotations. The stage should be controlled automatically in all four parameters of x, y and z
axes and rotation, θ, for an automatic driving stage. The preffered resolutions of the
micromanipulators operated by stepping motors are ≤0.1 µm and ≤1.5 µm for the single
mode and the multimode measurements, respectively. The sample stage should be
provided with a rotation control stage for coordinate axes alignment. The repeatability of
measurement is less than 1 % of designated dimension.

– 14 – 62496-2-2  IEC:2011
d) Input and output optical fibres
Select appropriate optical fibres for input and output light signal suitable to the core shape.
The core diameter of the fibre launching an optical signal into an OCB should preferably be
such that it is inscribed within the core shape, i.e. the fibre core profile is completely
contained within the waveguide core shape The core diameter of the fibre extracting an
optical signal from the OCB should preferably be such that it bounds the core shape i.e. the
waveguide core shape is completely contained within the fibre core profile. The input signal
should be stabilized in its mode using a mode filter.
e) Detection of contact of a fibre to an OCB
The touching of input/output fibres to an optical circuit board sample is automatically
detected and the distance from a port is kept constant to prevent damage to I/O ports.
f) Power meter
Prepare a power meter according to IEC 62496-2-1. Measure the optical power of an output
and feed-back to the movable stage in order to obtain the position where the maximum
optical power output is available in a short time.
g) Control system
This system controls the movable stage by the information of receiving optical power the
power monitor generates. Position information of input/output fibres at the maximum optical
power is recorded simultaneously. The control system also performs initialization of the
entire system, sending of image information to the monitor and automatic buckling
detection.
6.2.2.2.2 Procedure
a) Preparation
After the start of the system, check the absolute coordinate positions in the system of
driving stage, optical system for observation and input/output fibres (initialize); and warm up
the light source and power meter. A sample is fixed on an OCB holder.
b) Measurement
Adjust the coordinate axes of the sample and of the equipment using the coordinate giving
the direction of an axis. Move the sample to the position showing the coordinate origin
(displaying on the monitor a coordinate system giving the coordinate origin to adjust the
position), and then move the input/output fibres to the I/O ports whose positions are to be
measured. Adjust the optical centre to a port automatically and record its coordinate to the
control system. When there are multiple I/O ports, adjust one fibre first and then adjust the
next fibre. Repeat the adjusting process for all I/O ports. Coordinates of all the I/O ports
may be obtained by movement of a cable and adjustment of its position to a port when the
equipment can record approximate positions of all the ports.
6.3 Outer shape of optical circuit board
6.3.1 Method 1 (reference) – Use of observation system
6.3.1.1 Equipment
The equipment consists of the observation system, dimension measurement system and
data processing.
62496-2-2  IEC:2011 – 15 –
a) Observation
It is desirable that the observation system is equipped with both transmission light and
reflection light.
b) Dimension measurement
The dimension measurement system uses a movable stage with a digital scale as defined in
ISO 10360-2, or a digital scale having similar or better resolution. It is also possible that the
observation system of the equipment is equipped with a dimension measurement capability
of the same dimension measurement. It is also possible that the data processing section
has the same capability. In the case where the dimension measurement requires a similar
accuracy for the measurement of the printed wiring board, the measurement methods
stated in IEC 61189-2 shall be used.
c) Data processing
The data processing of the equipment has the capability of analyzing the image signal
taken from the observation system. It is desirable to have the ability to detect the brightness
difference of images. The data processing section may be omitted when the observation
system has dimension measuring capability.
6.3.1.2 Procedure
An example of the procedure is stated below.
a) Preparation
Magnification of the microscope is calibrated before measurement. The measurement stage
should be capable of being firmly fixed, or adhere a sample using a jig.
b) Measurement
Adjust the focusing position of the microscope and move the dimension measuring stage or
the microscope to a position where an edge of an optical circuit board can be clearly
observed. Obtain the outer dimension of the sample by the processing of imaging data from
a microscope or a camera. It is possible to confirm the measuring distance when the
microscope has a function of dimension measurement. In the case where the dimension
measurement requires a similar accuracy for the measurement of the printed wiring board,
the measurement methods stated in IEC 61189-2 shall be used.
6.3.2 Method 2 (alternative) – Use of dimensional drawing
The shape of the OCB or OCB body is checked by verification with the dimensional drawing
with dashed lines, which mean classified shape accuracy using the origin point or the
alignment mark as the standard point. An example of verification with a dimensional
drawing for a fibre flexible OCB is found in Figure 6. If the OCB body is within classified
shape accuracy, the OCB body is passed. The dimensional drawing is drawn on a
transparent sheet so that the verification is very easy.

– 16 – 62496-2-2  IEC:2011
Y-axis
YY--aaxixiss
YY--axaxiiss Dimensional drawing for
Dimensional drawing for
OOututOllutiine ne line oofof O Of OCCCBBB B B bodyodyody
shape acshape accuracycuracy
(boundary for classification)
(boundary for classification)
DDiimmensensiionaonall
Dimensional
drdrawawiingng
drawing
X-axis
X-axis
X-axis
XX--aaxixiss
OCB port
OOCCBB por portt
Origin point
OOrriiggiin pon poiintnt
Origin point
Alignment mark
Origin point Alignment mark
Transparent sheet
Transparent sheet
IEC  006/11 IEC  007/11
a) Dimensional drawing b) Verification of outer dimension
of OCB body
Figure 6 – Example of verification with a dimensional drawing for a fibre flexible OCB
6.4 Misalignment angle of I/O ports
6.4.1 Observation of cross section
Since the normal direction to a plane of I/O port is generally not aligned on a cross section
passing the core of optical circuit (z axis), as seen in Figures 7 and 8, the misalignment
angle could not be measured directly from one cross section. Thus, the misalignment angle
is estimated from observation of two orthogonal cross sections, as seen in Figure 9 a) and
b) and Figure 10 a) and b).
62496-2-2  IEC:2011 – 17 –
y
– x
π – θ
t
– z
z
θ
t
Optical axis
Optical circuit
I/O port
IEC  008/11
Figure 7 – Misalignment angle of I/O ports in end face I/O type OCB

Optical axis
z
θ
t
I/O port
Optical circuit
IEC  009/11
Figure 8 – Misalignment angle of I/O ports in surface I/O type OCB
In end face I/O type OCB, a vertical cross section passing the core axis of a waveguide is
observed to measure the vertical misalignment angle, θ (V). Also, a horizontal cross section
t
passing cores of arrayed waveguides is observed to measure the horizontal misalignment
angle, θ (H). On these cross sections, the angles between the outline of the I/O port and the
t
line perpendicular to the core axis are measured. Alternatively, the angles between the
perpendicular line to the outline of the I/O port and the extrapolated line (x axis) of the core
axis (z axis) are measured.
In surface I/O type OCB, a vertical cross section passing the core axis of a waveguide is
observed to measure the longitudinal misalignment angle, θ (Lg). Another vertical cross
t
section perpendicular to the previous cross section to measure θ (Lg) and across the
t
arrayed waveguides is observed to measure the lateral misalignment angle, θ (Lt). On these
t
cross sections, the angles between the perpendicular line to the outline of the I/O port and
the extrapolated line (-z axis) of the core axis (z axis) are measured.

– 18 – 62496-2-2  IEC:2011
y
θ (H)
t
y
θ (V)
t
x
x
z Optical circuit
z
Optical axis Optical axis
θ (V)
t θ (H)
Optical circuit
t
Side view
I/O port
Top view
I/O port
IEC  010/11
IEC  011/11
a) Vertical misalignment b) Rotation misalignment

Figure 9 – Parameters for misalignment angle in end face I/O type OCB

y
I/O port
x
I/O port
Cross section line for
side view
θ (Lt)
t
Optical circuit
z
Optical axis
Top view
z
θ (Lg)
t Front view Top view
y
x
Cross section line
for front view
Optical axis
Side view
IEC  012/11 IEC  013/11
a) Longitudinal misalignment angle b) Lateral misalignment angle
Figure 10 – Parameters for misalignment angle in surface I/O type OCB
6.4.1.1 Equipment
The equipment consists of an observation system, angle measurement system and data
processing section.
a) Observation
The observation system recognizes the optical waveguide core, outline of I/O port and
optical circuit board by means of an optical microscope or a camera.
b) Angle measurement
62496-2-2  IEC:2011 – 19 –
The angle measurement uses an angle measuring stage. It is also allowed that an angle
stage is overlapped on the image of the outline of the I/O port and waveguide core to
measure related misalignment angles. The data processing section may also have angle
measuring capability. It is also possible to determine an angle from a printed image on
paper using measures.
c) Data processing
This section has the capability of analyzing image information coming from the observation
system.
6.4.1.2 Procedure
A typical measuring procedure is described below.
a) Preparation
The magnification of the optical microscope is calibrated beforehand. Cut or lap the optical
circuit board to expose the core of an optical waveguide and the outline of an I/O port. Set
the measuring sample to the angle measuring stage.
b) Measurement
Adjust the microscope of an angle measuring stage to the position where the core of
waveguide and the outline of I/O port can be identified. Measure the angle from the image
data generated from the angle measuring stage or the camera.
c) Calculation
To obtain the misalignment angle θ from the components of angle measured from two
t
orthogonal cross sections, a calculation is required using the relation of three dimensional
angles in a rotation of Cartesian coordinate. It is possible to use an approximation equation
such as
2 2 2 2
sinθ ≈ sin θ (V) + sin θ (H) and sinθ ≈ sin θ (Lg) + sin θ (Lt) (1)
t t t t t t
These approximation equations are applicable when the components of the angle are small.
6.5 Mirror angle
6.5.1 Method 1 (reference) – Use of observation system
6.5.1.1 Equipment
The equipment consists of an observation system, dimension measurement system and
data processing section. A schematic diagram of the measuring equipment is illustrated in
Figure 1.
a) Observation
The observation system recognizes the optical waveguide, core, optical circuit board and
mirror by means of an optical microscope or a camera. It is desirable that the observation
system is equipped with both transmission light and reflection light. When using a lens, it
should be an aberration-free lens.
b) Dimension measurement
– 20 – 62496-2-2  IEC:2011
The dimension measurement uses a measuring stage having a scale to measure a
dimension. It is also possible that a sample stage or the observation stage has the
capability of measuring a distance. The data processing section may also have dimension
measuring capability. It is also possible to determine a distance from a printed image on
paper using measures.
c) Data processing
This section has the capability of analyzing image information coming from the observation
system. It is desirable that this section have the image analyzing capability of detecting
brightness information. It is possible to omit this data processing section in the equipment
when the observation system has the capacity of dimension measurement.
6.5.1.2 Procedure
A typical measuring procedure is described below.
a) Preparation
The magnification of the optical microscope is calibrated beforehand. Cut or lap the optical
circuit board to give a smooth and mirror faced cross section of the board that exposes the
optical waveguide and the face of exiting optical signal after reflecting from a mirror. Set the
measuring sample to the distance measuring stage.
b) Measurement
Adjust the focal point of an optical microscope and move the microscope of a distance
measuring stage to the position where either of mirror surface and core, optical waveguide
or optical circuit board can be identified. Derive the core dimension from the image data
generated from the distance measuring stage or the camera. It is also possible to confirm
the measuring object by the naked eye when the microscope is equipped with the
dimension measurement capability.
6.5.2 Method 2 (alternative) – Use of confocal microscope
6.5.2.1 Equipment
A confocal microscope with an objective lens of a high NA value (e.g. 0,95) and having a
software to analyze images obtained by the confocal microscope is used in measurement.
Figure 11 illustrates the schematic diagram for the measurement. The mirror face is open
as illustrated in the figure (the surface is not buried in transparent substance and
observable by the microscope).
a) Observation
The objective lens is of a magnification of x50 to x150 with an NA of 0,95, and should have
a large displacement distance and small aberration of any kind.
b) Data processing
The analyzing software should be able to define the reference face, to obtain coordinate
profile of the cross section of the lens, and be able to determine the angle stated in the
objects to be measured according to IEC 62496-4.
6.5.2.2 Procedure
a) Preparation
62496-2-2  IEC:2011 – 21 –
A sample is placed on the sample stage (its mirror surface is exposed upward) against the
objective lens.
b) Measurement
Move the sample (or the stage) as in the case using an microscope and have the mirror
face within the scope of the microscope. Select an appropriate magnification (x50 to x150
and NA of 0,95) and obtain the 3D profile of the sample in confocal observation mode, and
record the data. The profile at a mirror portion using confocal micros
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