IEC 62496-2-1:2011

Optical circuit boards - Part 2-1: Measurements - Optical attenuation and isolation

IEC 62496-2-1:2011 describes the various methods to measure the optical attenuation and isolation of optical circuit boards (OCBs).

Cartes à circuits optiques - Partie 2-1: Mesures - Affaiblissement et isolation optiques

la CEI 62496-2-1:2011 décrit les différentes méthodes utilisées pour mesurer l'affaiblissement et l'isolation optiques des cartes à circuits optiques (OCB, Optical Circuit Boards).

General Information

• Status: Published
• Publication Date: 27-Jul-2011
• 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-Jul-2011
• Completion Date: 28-Jul-2011

Overview

IEC 62496-2-1:2011 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies precise methods for measuring optical attenuation and optical isolation in optical circuit boards (OCBs). This standard is part of the IEC 62496 series focused on optical circuit board technology and is essential for ensuring performance consistency and quality control in fiber optic components used in advanced photonic and telecommunications systems.

The document covers standardized procedures, apparatus specifications, and measurement techniques-providing clear guidelines for accurate characterization of OCBs. It addresses both multimode and single-mode fiber measurements, offering detailed information for manufacturers, testing laboratories, and quality assurance engineers working in the field of optical circuit technology.

Key Topics

• Measurement Scope
  The standard describes different measurement methods to evaluate:

  • Optical attenuation (loss of optical power signal strength)
  • Optical isolation (ability to minimize cross-talk and back reflection between optical paths)

• Apparatus Requirements
  It defines suitable equipment for carrying out tests, including:

  • Optical sources with specific launch conditions (restricted launch for multimode fibers to control mode power distribution)
  • Power meters calibrated for optical power detection
  • Optical fibers and mode filters essential for maintaining repeatability and precision
  • Optical direction changing devices and temporary joints for setup flexibility

• Launch Conditions
  Detailed launch conditions ensure repeatable measurements:

  • Multimode fiber launch setups comply with IEC 62614 encircled flux requirements to achieve restricted mode launching
  • Single-mode fiber measurements follow IEC 61300-1 Annex B specifications for optimum coupling

• Measurement Procedures
  Various measurement approaches are standardized:

  • Cut-back method
  • Insertion methods (A, B, C, and D)
  • Mirror loss measurement
    These methods account for different configurations of OCBs and test system setups, ensuring comprehensive adaptability.

• Safety and Precautions
  The standard mandates compliance with IEC 60825-1 for laser safety, and emphasizes fiber positioning stability during measurement to avoid bending loss and data inconsistencies.

Applications

IEC 62496-2-1:2011 is highly relevant for industries and applications requiring precise optical circuit board characterization:

• Telecommunications
  Ensures optical circuit boards in networking equipment meet stringent attenuation and isolation requirements for high-speed data transmission.

• Integrated Photonics Manufacturing
  Assists in quality assurance during the fabrication of photonic integrated circuits and optical interconnects.

• Research & Development
  Facilitates comparative analysis of new OCB designs and materials for improved signal integrity and reduced losses.

• Test Laboratories
  Supports standard test methods for evaluating product conformity and optimizing optical component performance.

• Automotive and Aerospace
  Critical for applications involving reliable optical signal routing under harsh conditions where low attenuation and high isolation impact system resilience.

Related Standards

To support accurate implementation, IEC 62496-2-1 references and aligns with other important international standards in the optical and fiber optics domain:

• IEC 60793-2-10 & IEC 60793-2-50: Specifications for multimode and single-mode optical fibers
• IEC 60825-1: Safety requirements for laser equipment
• IEC 61300 series: Fiber optic interconnecting devices-test and measurement procedures
• IEC 62496-1: General specifications for optical circuit boards
• IEC 62614: Launch condition requirements for multimode attenuation measurements
• ISO 3599 & ISO 6906: Precision measurement tools relevant for dimensional control during optical assembly

Summary

IEC 62496-2-1:2011 provides essential guidelines for measuring optical attenuation and isolation in optical circuit boards, underpinning quality and performance assurance in the photonics industry. By adhering to this standard, organizations can ensure consistency and interoperability in optical components, thereby supporting the growing demands of high-speed optical communication and integrated photonics technologies.

Keywords: IEC 62496-2-1, optical circuit boards, OCB, optical attenuation, optical isolation, optical fiber measurement, multimode fiber, single-mode fiber, photonics testing, fiber optics standards, IEC standards, optical interconnects.

Standards Content (Sample)

IEC 62496-2-1 ®
Edition 1.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical circuit boards –
Part 2-1: Measurements – Optical attenuation and isolation

Cartes à circuits optiques –
Partie 2-1: Mesures – Affaiblissement et isolation optiques

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IEC 62496-2-1 ®
Edition 1.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical circuit boards –
Part 2-1: Measurements – Optical attenuation and isolation

Cartes à circuits optiques –
Partie 2-1: Mesures – Affaiblissement et isolation optiques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 33.180.01 ISBN 978-2-88912-572-2

– 2 – 62496-2-1 © IEC:2011
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Precautions . 6
4 Apparatus . 7
4.1 Launch conditions and source (S) . 7
4.2 Power-meter (D) . 7
4.3 Optical fibre (OF) . 8
4.4 Mode filter (MF) . 8
4.5 Optical direction changing device (OD) . 9
4.6 Temporary joint (TJ) . 9
5 Procedure . 10
5.1 Pre-conditioning . 10
5.2 Visual inspection . 11
5.3 Connectivity inspection . 11
5.4 OCB configurations and measurement methods . 11
5.5 Attenuation measurement with a power-meter . 13
5.5.1 General . 13
5.5.2 Cut-back method . 13
5.5.3 Insertion method (A) . 15
5.5.4 Insertion method (B) . 23
5.6 Isolation measurement with a power-meter . 25
5.6.1 Insertion method (C) . 26
5.6.2 Insertion method (D) . 31
5.7 Mirror loss measurement . 32
6 Details to be specified . 33
Bibliography . 34

Figure 1 – Launch apparatus for butt-joint connection, (a) without OD, (b) with OD . 10
Figure 2 – Cut-back method – Configuration A . 14
Figure 3 – Cut-back method – Configuration B . 15
Figure 4 – Insertion method (A) – Configuration A . 16
Figure 5 – Insertion method (A), multi port sequential measurements – Configuration A . 17
Figure 6 – Insertion method (A) – Configuration B . 18
Figure 7 – Insertion method (A) – Configuration C-1 . 19
Figure 8 – Insertion method (A) – Configuration C-2 . 20
Figure 9 – Insertion method (A) – Configuration D . 21
Figure 10 – Insertion method (A) – Configuration E . 22
Figure 11 – Insertion method (A) – Configuration E . 23
Figure 12 – Insertion method (B) – Configuration A . 24
Figure 13 – Insertion method (B) – Configuration C-1 . 25
Figure 14 – Insertion method (C) – Configuration A . 26
Figure 15 – Insertion method (C) – Configuration B . 27
Figure 16 – Insertion method (C) – Configuration C-1 . 28

62496-2-1 © IEC:2011 – 3 –
Figure 17 – Insertion method (C) – Configuration D . 29
Figure 18 – Insertion method (C) – Configuration E . 30
Figure 19 – Insertion method (C) – Configuration E . 31
Figure 20 – Insertion method (D) – Configuration A . 32
Figure 21 – Mirror loss measurement . 33

Table 1 – Preferred source and launch conditions . 7
Table 2 – Preferred launching and receiving fibres . 8
Table 3 – Measurement methods of attenuations . 11
Table 4 – Measurement methods of isolations . 12

– 4 – 62496-2-1 © IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL CIRCUIT BOARDS –
Part 2-1: Measurements –
Optical attenuation and isolation

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 62496-2-1 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
86/396/FDIS 86/401/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.

62496-2-1 © 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.
– 6 – 62496-2-1 © IEC:2011
OPTICAL CIRCUIT BOARDS –
Part 2-1: Measurements –
Optical attenuation and isolation

1 Scope
IEC 62496-2-1 describes the various methods to measure the optical attenuation and isolation
of optical circuit boards (OCBs).
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 60793-2-10, Optical fibres - Part 2-10: Product specifications - Sectional specification for
category A1 multimode fibres
IEC 60793-2-50, Optical fibres - Part 2-50: Product specifications - Sectional specification for
class B single-mode fibres
IEC 60825-1, Safety of laser products – Part 1: Equipment classification and requirements
IEC 61300-1, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 1: General and guidance
IEC 61300-3-1:2003, Fibre optic interconnecting devices and passive components – Basic
test and measurement procedures – Part 3-1: Examinations and measurements – Visual
examination
IEC 61300-3-4, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 3-4: Examinations and measurements – Attenuation
IEC 62496-1:2008, Optical circuit boards – Part 1: General
IEC 62614, Fibre optics – Launch condition requirements for measuring multimode
attenuation
ISO 3599, Vernier callipers reading to 0,1 and 0,05 mm
ISO 6906, Vernier callipers reading to 0,02 mm
3 Precautions
The requirements of IEC 60825-1 and the following test requirements shall be met.
The position of the fibres in the test should be fixed during the measurement to avoid changes
in attenuation caused by bending loss.

62496-2-1 © IEC:2011 – 7 –
4 Apparatus
4.1 Launch conditions and source (S)
For multimode measurements, a restricted launch, not an overfilled launch, shall be used.
Encircled flux, which is given in IEC 62614, shall be available for the purposes of launching
fibre qualification in case of a 50 or 62,5 graded index launch fibre. The required launch
conditions can be achieved by including appropriate equipment inside the light source, or by
applying mode filters on or in series with the launch cord.
For single-mode measurements, the launch condition shall be in accordance with Annex B of
IEC 61300-1.
The source unit consists of an optical emitter, the associated drive electronics and fibre pigtail.
Preferred source and launch conditions are given in Table 1.
Table 1 – Preferred source and launch conditions
No. Type Centre Spectral Stability Output Launch Source
o
wavelength width at 23 C power conditions type
nm nm dB/h
Laser diode or
a
S1 Multimode 660 ± 30 ± 0,05 TBD
≥30
LED
Laser diode or
a
S2 Multimode ± 0,05 TBD
780 ± 30 ≥30
LED
Laser diode or
a
S3 Multimode IEC 62614
850 ± 30 ≥30 ± 0,05
LED
Laser diode or
a
S4 Multimode TBD
980 ± 30 ≥30 ± 0,05
LED
Laser diode or
a
S5 Multimode 1 300 ± 30 ≥30 ± 0,05 IEC 62614
LED
IEC 61300-1, Laser diode or
a
S6 Single-mode 1 310 ± 30 ≤10 ± 0,05
Annex B.2.2 LED
IEC 61300-1, Laser diode or
a
S7 Single-mode 1 550 ± 30 ≤10 ± 0,05
Annex B.2.2 LED
a
The source output power shall be ≥20 dB above the minimum measured power level.
NOTE 1 Due to their long coherence length, laser source units create a speckle pattern across the core of a
multimode fibre that is unstable and which may render difficult or impossible the task of creating case 2 launch
conditions in a multimode component. Consequently, for measuring multimode components, lasers, should be
avoided in favour of LEDs or other incoherent source units.
NOTE 2 For S5 and S6, where an LED is used, the spectral width is more typically ≤150 nm.
NOTE 3 It is recognized that new components may require the use of other source types such as tunable lasers.
It is therefore recommended in these cases that the preferred source characteristics be specified on the basis of
the component to be measured.
4.2 Power-meter (D)
The power-meter unit consists of an optical detector, the mechanism for connecting to it and
associated detection electronics. The connection between the detector and a receiving fibre
will either be with an adaptor that accepts a bare fibre or a connector plug of appropriate
design.
The measurement system shall be stable within specified limits over the period of time
required to measure an optical power. For measurements where the connection to the
detector must be broken between the measurement of the optical power, the measurement

– 8 – 62496-2-1 © IEC:2011
repeatability shall be within 0,05 dB. A detector with a large sensitive area may be used to
achieve this requirement.
The precise characteristics of the detector shall be compatible with the measurement
requirements. The dynamic range of the power-meter shall be capable of measuring the
power level exiting from the OCB at the wavelength being measured. The preferred dynamic
range is from 40 dBm to -75 dBm.
4.3 Optical fibre (OF)
Optical fibres used for optical measurements shall meet the requirement of all categories of
class A fibres (multimode) given in IEC 60793-2-10, or class B fibres (single-mode) given in
IEC 60793-2-50. The preferred launching and receiving fibres are given in Table 2.
To measure an OCB consisting of a multimode waveguide, the launching fibre core diameter
should preferably be the same as the core inner diameter of the OCB or less, and the
numerical aperture (NA), which is the sine of the acceptance angle of a waveguide or fibre,
should be smaller than that of OCB. In this case, the most reproduceable attenuation value
could be obtained.
When using a launch fibre with a much smaller core diameter than that of the OCB, such as a
single-mode fibre, it is likely that a lower attenuation value will be obtained. The NA of a
single-mode fibre is much lower than the NA of the multimode OCB such that the launch beam
is less affected by the roughness of the core wall.
When measuring an OCB that employs optical fibre, a launching fibre shall be selected that
has the same geometrical and optical characteristics as that used in the OCB.
Table 2 – Preferred launching and receiving fibres
OCB medium Launching fibre Receiving fibre
Multimode fibre, 50 GI Multimode fibre, Multimode fibre with core diameter that
completely circumscribes the OCB output
or 62,5 GI Multimode fibre,
port, and with the same NA as the OCB
output port or more
Multimode waveguide or
Single-mode fibre
or
Direct detection by power-meter
Single-mode fibre, Single-mode fibre Multimode fibre,
Single-mode fibre
or
or
Single-mode waveguide
Direct detection by power-meter

4.4 Mode filter (MF)
The function of a mode filter is to eliminate measurement inaccuracies.
For single-mode measurements the mode filter shall include at least two metres of fibre with
two 50 mm-diameter loops.
Mode filters shall be placed between the source and the OCB and, where specified by the test
method, before the detector.
62496-2-1 © IEC:2011 – 9 –
4.5 Optical direction changing device (OD)
An optical direction changing device (OD) is a device by which the direction of incident light is
changed by 90 °. It may, for example, be a bending fibre, a flexible film waveguide, a fibre
with a flat (45 °) angled or curved mirror, or a waveguide with a flat (45 °) angled or curved mirror.
4.6 Temporary joint (TJ)
This is a method, device or mechanical fixture for temporarily aligning two fibre ends, a fibre
end and a waveguide end, or a waveguide end and a detector to form a stable, reproducible
and low-loss joint. It is used when the OCB cannot be directly connected to the measurement
system with a standard connector. It may, for example, be a fusion splice, a mechanical splice
realised with a precision V-groove, a butt joint realised with a micromanipulator, or a spatial
coupling. The temporary joint shall be stable to within ± 10 % of the measurement accuracy
required in dB over the time taken to measure optical power P. A suitable refractive index
matching material may be used to improve the stability of the TJ.
For the butt joint, the alignment of the system shall be adequate to ensure the reproducibility
or launched power. Figure 1(a) shows an example of the launch apparatus. Launching and
receiving fibres are mounted on XYZ and θ θ θ translation stages (micromanipulators), and
x y z
the OCB shall be placed between these fibre ends. The refractive index matiching material is
used between the OCB and the fibres. 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 input port of the OCB is connected to the fibre from the source (S), and the receiving fibre
to the detector (D) is positioned to the output port of the OCB. First, launching fibre position
shall be tuned to realize the minimum attenuation, i.e. maximize optical power captured by
receiving fibre. Then, receiving fibre position shall be tuned to realize the minimum
attenuation. After that, the launching and receiving fibre tuning shall be alternated until the
attenuation converges to the smallest value. A suitable refractive index matching material
filling the two gaps between the OCB and the two fibre ends may also improve the
measurement stability.
Alternatively, if it is not easy to detect the initial output power from the OCB by the receiving
fibre, the following method shall be used. The input port of the OCB is connected to the fibre
from the source, and then a large area detector is positioned over the output port. First
launching fibre position shall be tuned to realize the minimum attenuation, i.e. maximize
optical power captured by receiving detector. Then once launch fibre position is optimised,
replace detector at receiving end with receiving fibre, which is connected to detector, and tune
receiving fibre position until power captured by receiving fibre is maximized. After that, tune
the positions of the launching and receiving fibres in alternation until the attenuation
converges to the smallest value.
Figure 1(b) shows an example of the launch apparatus including an optical direction changing
device (OD). Launching and receiving fibres are joined to the ODs with 45 ° angled mirrors,
and are mounted on XYZ and θ θ θ translation stages (micromanipulators). The OCB shall be
x y z
placed perpendicular to the launching/receiving fibre directions. The input and output ports of
the OCB are connected to the 45 ° angled mirrors in OD. The launching and receiving fibre
tuning shall be performed in the same way as mentioned above.
NOTE Care should be taken in using the refractive index matching material. Residual matching material after the
measurement affects the performance of the following test. It also affects the reliability of the connecting part if the
measured OCB is connected with the fibre optic interconnecting device and so on. For the measurement of the
OCB with a 45 ° angled mirror, it is possible that the excess matching material attaches to the mirror surface. This
affects the performance of the measurement.

– 10 – 62496-2-1 © IEC:2011
TJ TJ
×
×
S D
MF MF
6 7 6
IEC  1551/11
（a） without OD
S D
1 5
2 2
TJ TJ
OD
OD
TJ
TJ
（b） with OD
IEC  1552/11
Key
1  Launching fibre mount
2  Fibre end
3  Fibre/channel waveguide
4  Printed circuit board
5  Receiving fibre mount
6  XYZ and θ θ θ translation stage (micromanipulator)
x y z
7 Optical circuit board
8 45 ° angled mirror
Figure 1 – Launch apparatus for butt-joint connection,
(a) without OD, (b) with OD
5 Procedure
5.1 Pre-conditioning
The optical interfaces of the OCB shall be clean and free from any debris likely to affect the
performance of the test and any resultant measurements. The manufacturer’s cleaning
procedure shall be followed.
NOTE Care should be exercised throughout the test to ensure that mating surfaces are not contaminated with oil,
grease, or refractive index matching material previously used in the test. It is recognized that bare fingers can
deposit a film of grease.
62496-2-1 © IEC:2011 – 11 –
5.2 Visual inspection
It is recommended that a visual inspection is made of the optical interfaces of the OCB in
accordance with IEC 61300-3-35 prior to the start of the test.
5.3 Connectivity inspection
Before the measurement, the relationship between the input and output ports of the OCB shall
be confirmed, that is, a from/to port table should be obtained. It is recommended that light is
transmitted through each optical path, and output light from each output port is observed with
a CCD camera or by a visual inspection.
NOTE 1 The preferred light source is a laser diode, LED, or lamp source (halogen or Xe). The wavelength is
arbitrary.
NOTE 2 When visible light or red light is used, a visual inspection may be useful.
5.4 OCB configurations and measurement methods
Table 3 and Table 4 show measurement methods of attenuation and isolation for each OCB
coinfigurations, respetively.
Table 3 – Measurement methods of attenuations
Measurement methods
OCB configuration Description
Reference Alternative
Configuration A Fibre to fibre Cut-back Insertion (A)
(4.1.2, IEC 62496- (OCB containing fibre or
1:2008) whose ends are outside Insertion (B)
the board)
Configuration B Flat end to flat end Insertion (A) Cut-back
(4.1.2, IEC 62496- (OCB made of optical
1:2008) fibre or channel
waveguide)
Configuration C-1 Mirror/grating to Insertion (A) Insertion (B)
(4.1.2, IEC 62496- mirror/grating
1:2008) (OCB made of channel
waveguide)
Configuration C-2 Mirror/grating to Insertion (A) None
(4.1.2, IEC 62496- mirror/grating
1:2008) (OCB made of slab
waveguide)
Configuration D Flat end to flat end in Insertion (A) None
(4.1.2, IEC 62496- groove or via-hole
1:2008) (OCB made of optical
fibre or channel
waveguide)
– 12 – 62496-2-1 © IEC:2011
Measurement methods
OCB configuration Description
Reference Alternative
Configuration E Mirror/grating to/from flat Insertion (A) None
(4.1.2, IEC 62496- end
1:2008) (OCB made of channel
waveguide)
NOTE This is one of
various types of
configuration E.
Table 4 – Measurement methods of isolations
Measurement methods
OCB configuration Description
Reference Alternative
Configuration A Fibre to fibre Insertion (C) Insertion (D)
(4.1.2, IEC 62496- (OCB containing fibre
1:2008) whose ends are outside
the board)
Configuration B Flat end to flat end Insertion (C) None
(4.1.2, IEC 62496- (OCB made of optical
1:2008) fibre or channel
waveguide)
Configuration C-1 Mirror/grating to Insertion (C) None
(4.1.2, IEC 62496- mirror/grating
1:2008) (OCB made of channel
waveguide)
Configuration C-2 Mirror/grating to None None
(4.1.2, IEC 62496- mirror/grating
1:2008) (OCB made of slab
waveguide)
Configuration D Flat end to flat end in Insertion (C) None
(4.1.2, IEC 62496- groove or via-hole
1:2008) (OCB made of optical
fibre or channel
waveguide)
Configuration E Mirror/grating to/from flat Insertion (C) None
(4.1.2, IEC 62496- end
1:2008) (OCB made of channel
waveguide)
Note: this is one of
various types of
configuration E.
NOTE There is no measurement method of isolation for configuration C.

62496-2-1 © IEC:2011 – 13 –
5.5 Attenuation measurement with a power-meter
5.5.1 General
The attenuation consists of "propagation loss" and "coupling loss", where the propagation loss
is the residual loss other than the coupling loss, which may stem from scattering and
absorption in the waveguide. The coupling loss occurs at the interfaces of the input and
output ports, where it depends on the mode field of the launching and receiving fibres.
Accordingly, the types, diameters, and NAs of the launching and receiving fibres that are
employed to measure the attenuation shall be described in the test report.
The attenuation measurement is based on the use of an optical power-meter.
Measuring the attenuation, A, requires two kinds of power to be measured using the power-
meter:
A = -10 log (P /P ) dB (1)
1 0
where
P is the power measured through the OCB. This power is the output power from a given port

of the OCB;
P is the power measured without the OCB in the circuit.
NOTE Before the measurement, a connectivity inspection shall be performed if the OCB has multiple input and
output ports.
5.5.2 Cut-back method
5.5.2.1 For configuration A, the attenuation measurement shall be in accordance with 5.4.1
of IEC 61300-3-4.
A mechanical splice realised with a precision V-groove or a fusion splice is used as a TJ. The
input port of the OCB is connected to the fibres from the source with the TJ. The given output
port is connected to the detectors, and P is measured. The fibre is cut at a cutting point (CP),
and P is measured (see Figure 2).
– 14 – 62496-2-1 © IEC:2011
××
DD
PP
MFMF
TTJJ
××
SS
MFMF
CPCP
aa
aa
aa--aa crcrooss sess sectctiioonn
TTJJ
SS
××× DD PP
IEC  1553/11
MFMFMF
Key
1 Optical circuit board
2 Fibre
Figure 2 – Cut-back method – Configuration A
5.5.2.2 For configuration B, the propagation loss can be measured with the cut-back method.
A butt joint is used as a TJ.
The attenuation, A , of an OCB of length L is measured. The OCB is cut at the output end
1 1
and A of the OCB, whose length is L , is measured. It is desirable to choose a cut-off length
2 2
such that there is a difference in the attenuation of more than 0,2 dB before and after the cut-
off of the waveguide. The cutting, dicing or routing tool should be of suitable quality to ensure
a consistent roughness profile with each application. The length of the cut waveguide is
measured using callipers as specified in ISO 3599 or ISO 6906. The attenuation should be
measured at least three times for each waveguide length.
The measured attenuations, A to A , are plotted against the waveguide lengths. The slope,
1 n
which shows the attenuation dependence on waveguide length, is calculated with the least
square fitting method and indicates the propagation loss (dB/cm) (see Figure 3). The slope
axis intercept indicates indicates the coupling loss.

62496-2-1 © IEC:2011 – 15 –
AA
TJTJTJ
TJTJTJ
DD
SS ××××
××××
MFMFMFMF
MFMFMFMF
LL
AA
TJTJTJ
TJTJTJ
DD
SS ×××× ××××
MFMFMFMF
MFMFMFMF
LL
AA
ｎｎ
TJTJTJ
TJTJTJ
DD
SS ××××
××××
MFMFMFMF MFMFMFMF
LL
AA
AA
AA [[ddBB]]
AA
ｎｎ
LL LL LL
ｎｎ 22 11
IEC  1554/11
LL [[ccm]m]
Key
1 Slope = propagation loss
2 Slope axis intercept = coupling loss
Figure 3 – Cut-back method – Configuration B
5.5.3 Insertion method (A)
The input port of the OCB is connected to the fibres from the source with TJ. The given output
port is connected to the fibres to the detectors with the TJ and P is measured. The fibres are
connected by TJ between the source and the detector and P is measured without the OCB
(see Figures 4 to 11). Several methods of connection between the fibres and the OCBs are
mentioned as follows:
5.5.3.1 For configuration A, a mechanical splice realised with a precision V-groove or a
fusion splice is used as a TJ. A schematic view of the connection method is shown in Figure 4.
The measured attenuation includes the coupling loss of TJ1. This method is much simpler and
easier than the cut back method. When mechanical splices realised with precision multi V-
grooves are used as TJs, output power measurements from multi output ports can be
achieved sequentially (see Figure 5).

– 16 – 62496-2-1 © IEC:2011
TJ
D
× P
MF
TJ1
×
S
MF
a
a
a-a cross section
TJ2
×
×
P
S D
IEC  1555/11
MF
MF
Key
1 Optical circuit board
2 Fibre
Figure 4 – Insertion method (A) – Configuration A

TTTJ1J1J1
SSS
××××
MFMFMFMF
62496-2-1 © IEC:2011 – 17 –
TTTJ1J1J1
SSS
××××
MFMFMFMF
TTTJ2J2J2
××××
×××× DDD
××××
××××
TTTJ1J1J1 MFMFMF
SSS
××××
MFMFMFMF
IEC  1556/11
Key
1 Optical circuit board
Figure 5 – Insertion method (A), multi port
sequential measurements – Configuration A
5.5.3.2 For configuration B, a butt joint is used as a TJ. A schematic view of the connection
method is shown in Figure 6.
The measured attenuation includes the coupling losses of TJ1 + TJ2 - TJ3. This depends on
the mode field of the launching and receiving fibre and the diameter/size of the
fibre/waveguide.
TTTJ1J1J1
SSS
××××
MFMFMFMF
– 18 – 62496-2-1 © IEC:2011
TTJ2J2
DDDD
××××××
PP
MFMFMFMFMFMF
TTJ1J1
××××××
SSSS
MFMFMFMFMFMF
aaaa
aaaa
aa--aa crcrooss sess sectctiioonn
TTJ3J3
××××××
××××××
PP
SSSS DDDD
IEC  1557/11
MFMFMFMFMFMF MFMFMFMFMFMF
Key
1 Optical circuit board
2 Fibre/channel waveguide
3 Printed circuit board
Figure 6 – Insertion method (A) – Configuration B
5.5.3.3 For configuration C-1, a butt joint is used as TJ. The OCB is placed perpendicular to
the launching/receiving fibre directions. The launching fibre is butt-jointed to the input port
(mirror/grating), and the output power from the given output port is confirmed with a CCD
camera (see 5.3). Then, the receiving fibre is butt-jointed to the output port (mirror/grating)
(see Figure 7).
The measured attenuation includes the mirror loss and the coupling losses of TJ1+ TJ2 - TJ3.
The coupling loss depends on the mode field of the launching and receiving fibres, the core
size of waveguide, and the thickness of the cladding on the core.

62496-2-1 © IEC:2011 – 19 –
a
a
P
MF 6
MF
b
DéDettaaiil bl of b
a-a cross section
Section a-a
P
TJ3
× ×
S D
MF MF
IEC  1558/11
Key
1 Optical circuit board
2 Mirror/grating
3 Channel waveguide
4 Printed circuit board
5 Core
6 Cladding
Figure 7 – Insertion method (A) – Configuration C-1
5.5.3.4 For configuration C-2, a butt joint is used as a TJ. The preferred receiving fibre shall
have a core diameter that completely circumscribes the OCB output port under measurement
(i.e. the cross-sectional profile of the output port is completely contained within the cross-
sectional profile of the receiving fibre core). A schematic view of the connection method is
shown in Figure 8.
The measured attenuation includes the mirror loss and the coupling losses of TJ1 + TJ2 - TJ3.
The coupling loss depends on the mode field of the launching and receiving fibres, and the
thickness of the cladding on the core.
TJ1
×
S
TJ2
× D
– 20 – 62496-2-1 © IEC:2011
a
a
P
Section a-a
a-a cross section
TJ3
×
S × D
P
MF IEC  1559/11
MF
Key
1 Output port
2 Input port
3 Optical circuit board
4 Mirror
5 Printed circuit board
6 Slab waveguide
Figure 8 – Insertion method (A) – Configuration C-2
5.5.3.5 For configuration D, a butt joint is used as a TJ. The fibre from the source is
connected to the OD of the input port with a TJ1. The OD of the given output port is
connected to the fibre from the detector with the TJ2. The ODs are connected to the input port
and output port of OCB with the TJ3 and the TJ4, respectively (see Figure 9).
The measured attenuation includes the excess losses of the ODs and the coupling losses of
TJ1 + TJ2 + TJ3 + TJ4 - TJ5. The coupling loss depends on the mode field of the launching
and receiving fibre, and the core sizes of the ODs.
TJ2
×
D
TJ1
× S
62496-2-1 © IEC:2011 – 21 –
a-a cross section
IEC  1560/11
Key
1 Open groove or via-hole
2 Optical circuit board
3 Fibre/waveguide
4 Light path
Figure 9 – Insertion method (A) – Configuration D
5.5.3.6 For configuration E (from mirror/grating to flat end type), a butt joint is used as a TJ.
The launching fibre is perpendicular to the OCB plane and is butt-jointed to the mirror/grating,
and the receiving fibre is butt-jointed to the flat end (see Figure 10).
The measured attenuation includes the mirror loss and the coupling losses of TJ1 + TJ2 - TJ3.
The coupling loss depends on the mode field of the launching and receiving fibres, and the
thickness of the cladding on the core.

– 22 – 62496-2-1 © IEC:2011
a
a
MF
P
TJ2
D ×
MF
b
4 3
DeDétatail oil bf b
Section a-a
a-a cross section
P
TJ3
S × × D
IEC  1561/11
MF MF
Key
1 Optical circuit board
2 Mirror/grating
3 Channel waveguide
4 Printed circuit board
5 Core
6 Cladding
Figure 10 – Insertion method (A) – Configuration E
5.5.3.7 For configuration E (from flat end to mirror/grating type), a butt joint is used as a TJ.
The launching fibre is butt-jointed to the flat end, and the receiving fibre is perpendicular to
the OCB plane and is butt-jointed to the mirror/grating (see Figure 11).
The measured attenuation includes the mirror loss and the coupling losses of TJ1 + TJ2 - TJ3.
The coupling loss depends on the mode field of the launching and receiving fibres, and the
thickness of the cladding on the core.
TJ1
× S
62496-2-1 © IEC:2011 – 23 –
a
a
P
MF
TJ1
×
S
MF
b
4 3
DeDétail otail bf b
Section a-a
a-a cross section
P
TJ3
×
S × D
IEC  1562/11
MF
MF
Key
1 Optical circuit board
2 Mirror/grating
3 Channel waveguide
4 Printed circuit board
5 Core
6 Cladding
Figure 11 – Insertion method (A) – Configuration E
5.5.4 Insertion method (B)
5.5.4.1 General
The input port of the OCB is connected to the fibre from the source with the TJ. The given
output port is connected to the detector, and P is measured. P is also measured (see
1 0
Figures 12 and 13). The methods of connection between the fibres and the OCBs are
mentioned as follows:
5.5.4.2 For configuration A, a mechanical splice realised with a precision V-groove or a
fusion splice is used as a TJ. Schematic view of connection method is shown in Figure 12.
The measured attenuation includes the coupling loss of TJ1. The method is much simpler and
easier than cut back method and insertion method (A).
TJ2
× D
– 24 – 62496-2-1 © IEC:2011
×
D
P
MF
TJ1
×
S
MF
a
a
Section a-a
a-a cross section
× P
S D
IEC  1563/11
MF
Key
1 Optical circuit board
2 Fibre
Figure 12 – Insertion method (B) – Configuration A
5.5.4.3 For configuration C-1, a butt joint is used as TJ1 between the OCB and the launching
fibre. A spatial coupling method is used as TJ2 between the OCB and the detector.
The OCB is placed perpendicular to the direction of the launching fibre, and the launching
fibre is butt-jointed to the mirrors/gratings. The detector is directly placed on a given output
port (see Figure 13).
The measured attenuation includes the mirror loss, and the coupling losses of TJ1 + TJ2. The
coupling loss of TJ1 depends on the mode field of the launching and receiving fibre, the core
size of waveguide, and the thickness of the cladding on the core. The coupling loss of TJ2 will be
largely caused by Fresnel reflections, rough facet surface scattering, as well as possible abberations
and diffraction effects, which will depend on the spatial coupling method.

62496-2-1 © IEC:2011 – 25 –
a
a
P
MF 6
D
b
Section a-a
Détail b
a-a cross section Detail of b
P
×
S
D
IEC  1564/11
MF
Key
1 Optical circuit board
2 Mirror/grating
3 Channel waveguide
4 Printed circuit board
5 Core
6 Claddi
...