IEC 62496-2-4:2013

Optical circuit boards - Basic test and measurement procedures - Part 2-4: Optical transmission test for optical circuit boards without input/output fibres

IEC 62496-2-4:2013 specifies the test method to decide whether to pass or fail an optical circuit board using direct illumination by a light. The input ports are directly illuminated and the optical intensity from the output ports of the optical circuit board is monitored using an area image sensor. Excess optical losses are the calculated from total detected intensities of light from a sample to be measured and from a control sample. This method is used to illuminate uniformly the input port of the optical circuit board (OCB) with a larger area than the core area, obtain the radiance of an area image from the corresponding output port of the OCB using an area image sensor, and evaluate whether to pass or fail using the radiance obtained compared to that of a control sample. The advantage of this test method is that the alignment procedure between a launch fibre and the OCB is not necessary. Key words: test method to decide whether to pass or fail an optical circuit board, OCB, area image sensor

Cartes à circuits optiques - Procédures fondamentales d'essais et de mesures - Partie 2-4: Essai de transmission optique des cartes à circuits optiques sans fibres d'entrée/sortie

La CEI 62496-2-4:2013 spécifie la méthode d'essai utilisée pour déterminer l'acceptation ou le rejet d'une carte à circuits optiques en la soumettant à l'éclairement direct d'une lampe. On soumet les ports d'entrée à un éclairage direct et on surveille l'intensité optique issue des ports de sortie de la carte à circuits optiques à l'aide d'un capteur d'image bidimensionnel. On calcule ensuite les affaiblissements optiques excédentaires à partir de la somme des intensités lumineuses détectées sur un échantillon à mesurer et sur un échantillon témoin. Cette méthode permet d'éclairer uniformément le port d'entrée de la carte à circuits optiques (OCB) sur une surface supérieure à celle du c ur, d'obtenir la luminance de l'image bidimensionnelle issue du port de sortie correspondant de l'OCB à l'aide d'un capteur d'image bidimensionnel, et d'évaluer s'il faut accepter ou rejeter la carte en comparant la luminance obtenue à celle d'un échantillon témoin. Cette méthode d'essai a pour avantage de ne pas nécessiter d'alignement entre une fibre d'injection et l'OCB. Mots clés: essai utilisée pour déterminer l'acceptation ou le rejet d'une carte à circuits optiques, OCB, capteur d'image bidimensionnel

General Information

• Status: Published
• Publication Date: 17-Jun-2013
• 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: 15-Jul-2013
• Completion Date: 18-Jun-2013

Overview

IEC 62496-2-4:2013 is an international standard developed by the International Electrotechnical Commission (IEC) focusing on optical circuit boards (OCBs). This standard defines a basic test and measurement procedure for assessing optical transmission in OCBs without input/output (I/O) fibres. The method prescribed uses direct illumination of the optical input ports and captures the emitted optical intensity from output ports through an area image sensor. By evaluating the relative optical losses compared to a control sample, the test determines if an optical circuit board passes or fails quality criteria.

The core advantage of this standard’s test method is the elimination of complex alignment processes between launch fibres and OCBs, permitting a more efficient, uniform, and reliable inspection process.

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Key Topics

• Direct Illumination Testing
  IEC 62496-2-4 specifies that the input ports of the OCB are uniformly illuminated over an area larger than the core to avoid the need for launch fibre alignment.

• Optical Intensity Monitoring Using Area Image Sensors
  Two-dimensional array sensors such as CCD or CMOS capture the radiance of the output ports, enabling high-resolution imaging and intensity measurement.

• Calculation of Excess Optical Loss
  The test calculates relative optical losses by comparing the total detected optical intensity of the sample with that of a known control sample, offering a quantitative pass/fail evaluation.

• No Input/Output Fibre Requirement
  The test targets optical circuit boards without attached fibres, enhancing testing efficiency for surface or end-face input/output designs.

• Measurement Conditions and Equipment Setup
  Includes specifications on light source systems, observation optics, data processing units, and sample holding mechanisms, ensuring repeatability and accuracy of results.

• Image Processing and Data Analysis
  Procedures for capturing images, binarization for port range detection, and calculation of summed pixel intensity form an essential aspect of the evaluation process.

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Applications

• Quality Assurance for Optical Circuit Boards
  Manufacturers can employ this test to verify that OCBs meet optical transmission standards before integration into larger optical communication systems.

• Production Line Inspection
  The standard facilitates quick and repeatable pass/fail results, ideal for inline testing and maintaining consistent manufacturing quality control.

• Non-Contact Inspection of OCBs
  Since fibre alignment is unnecessary, this method is beneficial for testing boards with delicate surfaces or complex geometries where physical fibre coupling is impractical.

• Evaluation of Optical Losses in Photonic Components
  The standard helps in diagnosing loss factors in OCBs, contributing to overall system performance optimization in optical communication networks.

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Related Standards

• IEC 62496 Series
  Part of the umbrella series covering basic test and measurement procedures for optical circuit boards, with additional parts addressing different configurations and test methods.

• IEC 60068-1: Environmental Testing
  Normatively referenced for environmental conditions during testing, ensuring robustness and reliability of test results under controlled environments.

• Other IEC Fibre Optics Standards
  Coordination with IEC Technical Committee 86 standards, which govern testing of fibre optic components and systems, to maintain harmonization across optical testing protocols.

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Keywords: optical circuit board test method, OCB optical transmission testing, area image sensor optical measurement, IEC 62496-2-4, optical loss measurement, non-contact optical testing, fibre-free optical board inspection, optical quality assurance, IEC optical standards, photonic device testing.

Standards Content (Sample)

IEC 62496-2-4 ®
Edition 1.0 2013-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical circuit boards – Basic test and measurement procedures –
Part 2-4: Optical transmission test for optical circuit boards without input/output
fibres
Cartes à circuits optiques – Procédures fondamentales d'essais et de mesures –
Partie 2-4: Essai de transmission optique des cartes à circuits optiques sans
fibres d'entrée/sortie
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IEC 62496-2-4 ®
Edition 1.0 2013-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical circuit boards – Basic test and measurement procedures –

Part 2-4: Optical transmission test for optical circuit boards without input/output

fibres
Cartes à circuits optiques – Procédures fondamentales d'essais et de mesures –

Partie 2-4: Essai de transmission optique des cartes à circuits optiques sans

fibres d'entrée/sortie
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX S
ICS 33.180.01 ISBN 978-2-83220-868-7

– 2 – 62496-2-4 © IEC:2013
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviations . 6
3.1 Terms and definitions . 6
3.2 Abbreviations . 7
4 Measurement conditions . 7
5 Inspection methods . 8
5.1 Equipment . 8
5.1.1 Light source system . 9
5.1.2 Observation system . 10
5.1.3 Data processing unit . 11
5.1.4 Unit for holding the sample . 12
5.2 Measurement procedures of relative optical loss . 12
5.2.1 Preparation of light source . 12
5.2.2 Preparation of the optical observation system measuring equipment . 13
5.2.3 Measuring coordinates of I/O ports . 13
5.2.4 Capturing of optical images for control sample and samples to be
measured . 13
5.2.5 Image data processing (detection of I/O port range) . 14
5.2.6 Calculation of relative loss . 14
5.3 Evaluation of pass or fail . 15
Annex A (informative) Example of an optical transmission test for an OCB without I/O
fibres . 16
Annex B (informative) Measurement of input and output ports in offset positions . 19
Bibliography . 21

Figure 1 – Optical transmission test system without I/O fibres for surface I/O type OCB . 8
Figure 2 – Optical transmission test system without I/O fibres for end-face I/O type
OCB . 9
Figure 3 – Schematic diagram of measurement of uniformity of illumination area . 10
Figure 4 – Example of obtained uniformity of illumination area . 10
Figure 5 – Example of obtained sensitivity of an image sensor (input uniformity within
1 %) . 11
Figure 6 – Position alignment of light source . 13
Figure 7 – Example of captured image and extracted I/O port range by image
binarization . 14
Figure 8 – Calculation of the total detected intensity of extracted I/O port range from
detected intensity for each pixel . 15
Figure A.1 – Example of relative optical loss measurement . 17
Figure A.2 – Example of reproducibility of relative optical loss measurement . 18
Figure B.1 – Ray traces for OCBs with mirror having designated mirror angle (left) and
not designated one (right) . 19
Figure B.2 – Difference of focus positions between without offset and with offset . 20
Figure B.3 – Optical images at surface of OCB plane (without offset) and offset
position (with offset). 20

62496-2-4 © IEC:2013 – 3 –
Table A.1 – Observation system . 16
Table A.2 – Light source . 16
Table A.3 – Samples to be measured . 16

– 4 – 62496-2-4 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL CIRCUIT BOARDS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 2-4: Optical transmission test for optical circuit boards
without input/output fibres
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 62496-2-4 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
86/449/FDIS 86/456/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.

62496-2-4 © IEC:2013 – 5 –
A list of all parts of the IEC 62496 series, published under the general title Optical circuit
boards – Basic test and measurement procedures, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
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 – 62496-2-4 © IEC:2013
OPTICAL CIRCUIT BOARDS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 2-4: Optical transmission test for optical circuit boards
without input/output fibres
1 Scope
This part of IEC 62496 specifies the test method to decide whether to pass or fail an optical
circuit board using direct illumination by a light. The input ports are directly illuminated and
the optical intensity from the output ports of the optical circuit board is monitored using an
area image sensor. Excess optical losses are the calculated from total detected intensities of
light from a sample to be measured and from a control sample. This method is used to
illuminate uniformly the input port of the optical circuit board (OCB) with a larger area than the
core area, obtain the radiance of an area image from the corresponding output port of the
OCB using an area image sensor, and evaluate whether to pass or fail using the radiance
obtained compared to that of a control sample.
The advantage of this test method is that the alignment procedure between a launch fibre and
the OCB is not necessary.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms, definitions and abbreviations apply.
3.1.1
shading
non-uniformity of detected intensity of an image caused by non-uniformity of the sensitivity of
elements of an area image sensor and vignetting depending on the optical system
Note 1 to entry: Correction of the non-uniformity of the detection sensitivity of elements of a uniform one is called
"shading correction".
3.1.2
gamma value
factor “γ” for a camera expressed by the following equation:
γ
(input optical intensity signal) = A × (output image signal)
where A is a proportionality constant
Note 1 to entry: The input optical intensity is linearly proportional to the output image signal when γ = 1.

62496-2-4 © IEC:2013 – 7 –
3.1.3
telecentric optical system
optical system where the optical input pupil and output pupil are placed at infinitely far
positions and the main optical signal is parallel to the optical axis
3.1.4
distortion
(distortion aberration)
type of aberration
Note 1 to entry: The optical image is not in proportion to the original target but is distorted. There are two types of
distortion: one is the barrel type, where light is distorted outward; the other is the bobbin or pincushion type, where
light is distorted inward near the edge of a lens.
3.1.5
area image sensor
arrayed photo-detector in two dimensions, which can capture area image at once
Note 1 to entry: There are two types of area image sensor: one is the CCD (charge coupled device); the other is
the CMOS (complementary metal oxide semiconductor).
3.1.6
control sample
sample having optical insertion loss already obtained by measurement procedure specified in
IEC 62496-2-1 [1]
Note 1 to entry: The core shape and numerical aperture of the control sample should be same as those of the
samples to be measured.
3.1.7
relative optical loss
difference between the total detected intensity obtained from the output port area of the
sample to be measured and that for a control sample
Note 1 to entry: The unit of relative optical loss is the decibel.
3.2 Abbreviations
ACC automatic current control
APC automatic power control
CCD charged couple device
CMOS complementary metal oxide semiconductor
LED light emitting diode
NA numerical aperture
OCB optical circuit board
4 Measurement conditions
All measurements are made under the conditions specified in IEC 60068-1, unless otherwise
specified.
___________
Figures in square brackets refer to the Bibliography.

– 8 – 62496-2-4 © IEC:2013
5 Inspection methods
5.1 Equipment
The test equipment shall consist of a light source system, an observation system, a sample
holder and a data processor (image intake and image processor). The construction illustrated
in Figure 1 should be used to the surface I/O port type OCB. The system illustrated in
Figure 2 should be used for end-face I/O type OCB.
Movement and adjustment of positions of irradiation for and detecting images from the sample
should be carried out by the adjustment mechanisms provided to the light signal illuminator,
observation optics and sample holder.

Key
A1 light source system p1 stage controller
A2 data processing system S1 stage
A3 observation system c1 camera
L1 light source OC optical circuit board
HS unit for holding sample LA uniform light
DP data processor CI captured image

Figure 1 – Optical transmission test system without I/O fibres for surface I/O type OCB

62496-2-4 © IEC:2013 – 9 –
Key
A1 light source system p1 stage controller
A2 data processing system S1 stage
A3 observation system c1 camera
L1 light source OC optical circuit board
HS unit for holding sample LA uniform light
DP data processor CI captured image

Figure 2 – Optical transmission test system without I/O fibres for end-face I/O type OCB
5.1.1 Light source system
5.1.1.1 Light source
The light source to be used is an incoherent light source, such as an LED, in order to prevent
inducing a speckle pattern to the output image pattern to give a large numerical aperture
divergent input to ensure fully filled waveguide modes. It is desirable that the light source is
equipped with an APC to stabilize the output optical power by signal feedback from an
optical power monitor. ACC is substituted for APC if the required optical stability is attained
without use of an APC.
5.1.1.2 Holding and position adjustment of the light source
Holding and position adjustment functions of the light source shall be provided to adjust and
control the light source position to the light input port of the sample to be measured.
5.1.1.3 Illumination condition
An illumination method shall be used that provides uniform light illumination to the optical
circuit within a specified illumination intensity range. Ensure numerical aperture (NA) is
greater than that of the optical circuit. The uniformity of illumination is confirmed by measuring,
using a scanning optical fibre having similar core shape and NA to those of the OCB pointing
in the same direction as the waveguide or fibres in the OCB to be measured or by using the
OCB to be measured as a probe. A schematic diagram of measurement of uniformity of the
illumination area is shown in Figure 3. An example of the measurement result is shown in

– 10 – 62496-2-4 © IEC:2013
Figure 4. The uniformity of the illumination to be used should be sufficient for the required
accuracy of the measurement.
L1
PM
OP
IEC  1436/13
Key
L1 light source
OP optical fibre as a probe
PM optical power meter
Figure 3 – Schematic diagram of measurement of uniformity of illumination area

–2,5
–2,0
–1,5
99-100
–1,0
98-99
–0,5
0,0
97-98
0,5
96-97
1,0
1,5
95-96
2,0
2,5
X (mm)
IEC  1437/13
NOTE 1 The unit in the legend is in percentage.
NOTE 2 The maximum intensity is normalized to 100 %.
Figure 4 – Example of obtained uniformity of illumination area
5.1.2 Observation system
5.1.2.1 Optical system for observation of the image from the output ports
It is desirable to use a telecentric optical system to attain good measurement accuracy within
the image measuring area. It is also recommended to use an optical system with minimum
shading in the system to keep uniformity of the optical performance within the measuring
area.
2,5 mm
3,5 mm
–2,5
–2,0
–1,5
–1,0
–0,5
0,0
0,5
1,0
1,5
2,0
2,5
Y (mm)
62496-2-4 © IEC:2013 – 11 –
The NA of the optical system should be larger than that of the optical wiring to receive all the
light output coming from the output port. The magnification of the observation system shall be
chosen depending on the core size to be measured and the specification of the area image
sensor (pixel number and size). The number of pixels in the output emission area, which is
the extracted area by the image binarization method for one core shape of OCB, should be
larger than 200.
5.1.2.2 Area image sensor
The area image sensor used in the measuring system may be a digital still camera using an
area image sensor or a digital video camera. The area image sensor shall have the necessary
sensitivity to the light used for optical information transmission. The image sensor to be used
shall have a sufficient range of linearity to attain enough resolution of detected intensity for
analysis of data. The area image sensor linearity between input optical light signal and output
image signal shall be suitably ensured. Figure 5 shows an example of the sensitivity of an
image sensor.
9999 --100100
500 98-99
98 - 99
97-98
97 - 98
96-97
96 - 97
959 5--9696
94-95
94 - 95
–100
9393 --9494
–200
–300
92-93
92 - 93
–400
9191 --9292
–500
90 - 91
90-91
–600
X (µm)
IEC  1438/13
NOTE 1 The unit in the legend is in percentage.
NOTE 2 The maximum intensity is normalized to 100 %.
Figure 5 – Example of obtained sensitivity of an image sensor
(input uniformity within 1 %)
5.1.2.3 Holding and position adjustment of the optical system
Holding and position adjustment functions of the optical system shall be provided to adjust
and control the optical system position to the light output port of the sample to be measured.
5.1.3 Data processing unit
The data processing unit shall be used to judge if a test sample meets the requirements
based on the selection of the optical output area from which light is emitted, calculation of
total detected intensity in the area from which light is emitted, and relative optical loss
evaluation in the output port area from which light is emitted. The analysis may be made after
recording an optical image. However, it is desirable to perform necessary image processing
while the measuring point is moved from one point to another, if the analysing equipment has
650 µm
650 µm
–400
–300
–200
–100
Y (µm)
– 12 – 62496-2-4 © IEC:2013
sufficient capability of data processing. It is also desirable to have the capability of shading
corrections to compensate non-uniformity on the plane caused by non-uniformity of the optical
observation system and of the image sensor used. The processing system should have the
capability of initializing the entire observation system, motion control of the sample holding
stage and recording of observed data.
5.1.4 Unit for holding the sample
5.1.4.1 Moving the sample
The sample holding mechanism shall have a stage in the X-direction (in the direction of input
and output ports) to change the measurement position of a sample. A θ-stage should also be
provided in the stage if angle alignment is required in the sample holding stage. Y-direction
movement of the stage and/or system for the illuminating light source and observing stage
should also be used when light control may not be made by X-direction movement of the
stage only. It may also be possible to use a sample holding stage without motion capability
depending on whether the construction of the observing stage by the movement mechanisms
of the light source and of the observing optical scheme are sufficient to adjust the observation
scheme. If necessary, other direction movements such as Z-direction and two rotational axes
are provided in the mechanism as an option.
5.1.4.2 Holding the sample
A sample holding stage shall be capable of holding various samples to be measured. A
flexible sample should be fixed on a rigid board or a holder designed for especially flexible
OCB without any bending in order to avoid developing a misalignment of optical axes between
the I/O ports of OCB and optical systems of irradiation and observation. A sample shall be
held on the sample holding stage firmly using suction and/or holding tape. In the case of
surface ports, the distance between the stage for the sample to be measured and optical
observation stage should not be varied within the observation range to keep the focus of the
observing surface and not to de-focus an image.
5.2 Measurement procedures of relative optical loss
5.2.1 Preparation of light source
The light source should be sufficiently warmed up before use for stability. Calibrate the output
power of the light source using a standard sample for the system. Obtain the total detected
intensity at the output port as in the case of a usual test. The conditions of the gain and
exposure time for the area image sensor shall be the same. Check the entire optical system
when the total detected intensity is significantly different from the value for usual
measurement.
The position of the light source shall be checked. The centre of illumination shall be at the
centre of the injection light point (centre of tolerance curve) as shown in Figure 6. The centre
of illumination is found by a similar method to calculation of the centre of mass or inertia or
put it half way between the –3 dB points. The first is better but the second is more convenient.
For example, when the tolerance curve is set at the colour keys 99 % to 100 % shown in
Figure 4, the centre of illumination is at the position (0,5, –0,25).

62496-2-4 © IEC:2013 – 13 –
Intensity
LA CL
Y
X
OC
X-axis position
IEC  1439/13
Key
LA uniform light area
CL centre of ilulmination area
OC OCB to be measured
Figure 6 – Position alignment of light source
5.2.2 Preparation of the optical observation system measuring equipment
The area image sensor should be sufficiently warmed up before use for stability. The focus
adjustment of the observation optical system is the adjustment of the focus point to the output
port of the OCB. If the focal point position changes, the focal point position shall be adjusted
to bring it back to original position.
Adjust the light power of the source, gain of the image sensor and exposure time for proper
image data acquisition. Select a proper number of measurements. The detected intensity of
the measurement image shall be adjusted as not to saturate the measuring detected intensity.
5.2.3 Measuring coordinates of I/O ports
The measuring coordinates of I/O ports to be measured shall be defined using designed or
effective position data.
5.2.4 Capturing of optical images for control sample and samples to be measured
Obtain an optical image of a control sample for relative optical loss evaluation of optical loss
of measurement samples to the control sample. Set the control sample to the measurement
point on the stage (or move the light source and observing optical scheme to the
measurement point of the control sample). Capture the output optical image coming from the
output port by an observation optical system.
Move the measuring sample to the original measurement position (or move the light source
and observation scheme to the measurement position of the sample). Obtain the optical
image from the sample, as in the case for the control sample. Move the observing optical
Intensity
Y-axis position
– 14 – 62496-2-4 © IEC:2013
system to the next observing position and obtain an optical image as before. Repeat the
procedure to the end of the measurement.
5.2.5 Image data processing (detection of I/O port range)
The optical data thus obtained are processed to extract an area by image binarization, which
is defined as an I/O port range. The I/O port range is the inside area of the obtained output
optical signal coming through the samples. An example of an extracted I/O port range by
image binarization is shown in Figure 7. The selection rule of the I/O port range shall be
agreed between user and supplier and be clearly specified between them.

Key
CI captured image
EP extracted area (I/O port range)
IP intensity profile of captured image
Figure 7 – Example of captured image and extracted I/O port range
by image binarization
There is a possibility of a problem detecting the correct optical image in the I/O port range
when the optical intensity in the cladding is very large.
5.2.6 Calculation of relative loss
Calculate the total detected intensity of the I/O port range from the above-mentioned image
processing obtaining the detected intensity of each pixel for all pixels, as shown in Figure 8.
The total detected intensity B is the sum of the detected intensity of all the pixels within the
image in the output image range as follows:

where b is the detected intensity for number i pixel.
i
The number of pixels for one I/O port range should be larger than 200.

62496-2-4 © IEC:2013 – 15 –
1 pixel
b b b b …
1 2 3 4
b
…
n
IEC  1441/13
Key
b luminance for number i pixel
i
Figure 8 – Calculation of the total detected intensity of extracted I/O port range
from detected intensity for each pixel
Process the image of a standard sample image and calculate the total detected intensity. The
total detected intensity here obtained is B . Measure the light output coming through a
control
sample. The total detected intensity in this case is B . The relative optical loss of the
sample
sample to the standard sample is as follows:
Relative optical loss = –10 log {(B )/(B )}(dB)
sample control
5.3 Evaluation of pass or fail
Pass or fail of the sample is judged from the attained relative optical loss to the control
sample. The criteria of relative optical loss are based on the agreement between user and
supplier.
– 16 – 62496-2-4 © IEC:2013
Annex A
(informative)
Example of an optical transmission test for an OCB without I/O fibres
A.1 Measurement system
A.1.1 Observation system
Table A.1 shows an example of specifications for an observation system.
Table A.1 – Observation system
Magnification × 5
NA of receptor 0,4
Effective observation range 1,28 × 0,96 (mm)
Pixel pitch after magnification
0,93 (µm/pixel)
Intensity level 12 bit
A.1.2 Light source
Table A.2 shows an example of specifications for a light source.
Table A.2 – Light source
Light source (wavelength)
LED ( 850 nm, △=100 nm)
Uniform illumination range
1 mmφ (± 1 %)
The value is greater than the effective observing
range
NA of illumination 0,57
A.2 Samples to be measured
Table A.3 shows samples to be measured. One of 10 samples was used as a control sample.
Table A.3 – Samples to be measured
OCB type Surface I/O type with 45° mirrors at both ends
Core size Core height: 50 µm
Core width (top and bottom): 70 µm
NA of OCB 0,3
Number of samples 10
A.3 Measurement example of relative loss
Figure A.1 shows relative optical losses obtained with the number 3 sample, which has the
lowest optical loss, as a control sample in this measurement.

62496-2-4 © IEC:2013 – 17 –
A relatively large loss for the number 6 sample was observed in comparison with other
samples. If the pass/fail criterion is 0,5 dB, the number 6 sample becomes “not good”. Photos
of captured reflected light images for the number 1 and number 6 samples are also shown.

A B
0,0
Pass
–0,5
–1,0
Fail
–1,5
–2,0
–2,5
–3,0
1 2 3 4 5 6 7 8 9 10
Number of the OCB
Photos of images by mirror-reflection light
Input A Input B
Number Number Number Number
1A 1B 6A 6B
OK NG
IEC  1442/13
Figure A.1 – Example of relative optical loss measurement
A.4 Reproducibility of relative optical loss measurement
The reproducibility of the measured data of relative optical loss was checked by measuring an
optical board repeatedly ten times and comparing the measured value for each time with the
average. The sample was removed from the sample holder and replaced every time. The
vertical extent of the range of data points indicates the sizes of error bars which could be
used for this measurement.
Relative optical loss  (dB)
– 18 – 62496-2-4 © IEC:2013
120,0
110,5
110,0
100,5
100,0
99,5
99,0
98,5
98,0
1 2 3 4 5 6 7 8 9 10
Number of the OCB
IEC  1443/13
Figure A.2 – Example of reproducibility of relative optical loss measurement
Total counts normalized by
the average value  (%)
62496-2-4 © IEC:2013 – 19 –
Annex B
(informative)
Measurement of input and output ports in offset positions
B.1 Measurement of the position of an I/O port at an offset position
B.1.1 General
A photodetector may be mounted on the surface I/O type OCB in an example case. The
detecting plane of the photodetector is not on the surface of the OCB. Thus, there is gap
between the surface of OCB and the detecting plane of the photodetector. Measurement of
the centre of a light spot emitted from the OCB at the detecting plane of photodetector is
required. There is a possibility that the position of the output light signal may shift from the I/O
port positions when the position of the output light is offset from the port, caused by a
deviation of the mirror angle with respect to the surface plane of the OCB as shown in Figures
B.1, B.2 and B.3. The shift of the spot position at the position where an image recording
device is placed (offset position) can be calculated by comparison of the offset position of the
light beam and the positions of I/O ports of the OCB for measurement. The position of the
centre of the light spot at an offset position is calculated as the centre of the observed light
spot.
SF
AP
RY1 RY1
OF
RY2
OC OC
ML2
ML1
IEC  1444/13
Key
OC optical circuit board
ML1 mirror with designated mirror angle with respect to surface of OCB
ML2 mirror with non designated mirror angle with respect to surface of OCB
RY1 ray during propagation into core, reflecting at mirror and emtited from OCB with ML1
RY2 ray during propagation into core, reflecting at mirror and emitted from OCB with ML2
SF shift due to difference of mirror angles between ML1 and ML2
AP effective position of optical device mounted on OCB
OF gap between surface of OCB and AP
Figure B.1 – Ray traces for OCBs with mirror having designated
mirror angle (left) and not designated one (right)
B.1.2 Procedure
An optical image is obtained as the light is focused on the OCB. The focal point is shifted in
the direction of the output optical beam as specified. The brightness of the output spot is
somewhat decreased due to divergence of the output light beam. The power of the light
source and gain and shutter speed of the area image sensor may be adjusted if it is difficult to
detect the position of the output light spot using the same conditions as for the surface
observation of the OCB. Coordinates of the I/O ports of the OCB and centre coordinate of the
spot at offset are obtained from the images obtained before and after the offset to calculate
the variation.
– 20 – 62496-2-4 © IEC:2013
LE
AP
OC FP
FP
OF
ML
ML
IEC  1445/13
Key
LE lens
FP focus point
ML mirror
OC optical circuit board
ML mirror
AP effective position of optical device mounted on OCB
OF gap between surface of OCB and AP
Figure B.2 – Difference of focus positions between without offset and with offset

BO AO
CI1
∆Y
CI2
∆X
IEC  1446/13
Key
BO captured image without offset
AO captured image with offset
CI1 centre positon of I/O port range without offset
CI2 centre position of I/O port range with offset
NOTE ∆X and ∆Y are shifts of the centre position of I/O port range along the X- axis and Y axis, respectively,
which are due to the offset.
Figure B.3 – Optical images at surface of OCB plane (without offset)
and offset position (with offset)
When the sample has warpage in the vicinity of I/O ports with respect to the sample holding
stage, the obtained position of the I/O ports has uncertainty. Care should be taken to avoid
this kind of error. For example, an angle deviation of 5° and an offset of 100 µm at the setting
of the sample may give a coordinate shift of approximately 9 µm.

62496-2-4 © IEC:2013 – 21 –
Bibliography
[1] IEC 62496-2-1, Optical circuit boards – Basic test and measurement procedures – Part
2-1: Measurements – Optical attenuation and isolation
Additional non-cited references
IEC 60793-2, Optical fibres – Part 2: Products specification –
IEC 62496 (all parts), Optical circuit boards – Basic test and measurement procedures
IVES, D.J., FERGUSON, R. HARRIS,S. “Development of a variable launch attenuation and
isolation measurement system for optical waveguides,” Applied Optics, vol. 50, no. 22,
pp. 4268-4275, Aug. 2011.
_____________
– 22 – 62496-2-4 © CEI:2013
SOMMAIRE
AVANT-PROPOS . 24
1 Domaine d'application . 26
2 Références normatives . 26
3 Termes, définitions et abréviations . 26
3.1 Termes et définitions . 26
3.2 Abréviations . 27
4 Conditions de mesure . 28
5 Méthodes d'examen. 28
5.1 Equipement . 28
5.1.1 Système de source de rayonnement lumineux . 29
5.1.2 Système d'observation . 31
5.1.3 Système de traitement de données . 32
5.1.4 Système de maintien de l'échantillon . 32
5.2 Procédures de mesure de l'affaiblissement optique relatif . 32
5.2.1 Préparation de la source de lumière . 32
5.2.2 Préparation de l'équipement de mesure du système d'observation
optique . 33
5.2.3 Coordonnées de mesure des ports d’E/S . 33
5.2.4 Capture d'images optiques pour l'échantillon témoin et les
échantillons à mesurer . 34
5.2.5 Traitement des données d'image (détection de la plage des
ports d’E/S) .
...