IEC TR 62150-7:2024

IEC TR 62150-7 ®
Edition 1.0 2024-09
TECHNICAL
REPORT
colour
inside
Fibre optic active components and devices – Test and measurement procedures –
Part 7: Calculation methodology of laser safety class for optical transceivers and
transmitters
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IEC TR 62150-7 ®
Edition 1.0 2024-09
TECHNICAL
REPORT
colour
inside
Fibre optic active components and devices – Test and measurement procedures –

Part 7: Calculation methodology of laser safety class for optical transceivers

and transmitters
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.20  ISBN 978-2-8322-9657-8

– 2 – IEC TR 62150-7:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Calculation methodology. 7
4.1 General . 7
4.2 Wavelength . 8
4.3 Time base . 8
4.4 Hazard for eye and skin . 8
4.5 Class categories . 9
4.6 Measurement conditions 1, 2, and 3 . 9
4.7 Correction factors . 12
4.8 Class 1 and Class 1M power calculations . 13
5 Example of calculations . 14
5.1 Class 1 power for MMF applications between 700 nm and 1 050 nm
wavelength . 14
5.2 Class 1 power for SMF applications between 1 200 nm and 1 400 nm
wavelength . 15
5.3 Class 1 power for SMF applications between 1 400 nm and 1 650 nm
wavelength . 16
6 Specific interface applications . 17
6.1 Applications with wavelength-division multiplexing (WDM) . 17
6.2 Fibre array applications. 17
Annex A (informative) Hazard level calculations . 19
A.1 General . 19
A.2 Example of calculations . 19
A.2.1 MMF applications at wavelengths between 700 nm and 1 050 nm . 19
A.2.2 SMF applications at wavelengths between 1 200 nm and 1 400 nm . 21
A.2.3 SMF applications at wavelengths between 1 400 nm and 1 650 nm . 22

Figure 1 – Graphic illustration of distance to source and aperture stop . 9
Figure 2 – Class 1 power P for MMF applications . 15
imax
Figure 3 – Class 1 power P for SMF applications (1 200 nm < λ < 1 400 nm) . 16
imax
Figure 4 – Class 1 power P for SMF applications (1 400 nm < λ < 1 650 nm) . 16
imax
Figure A.1 – Maximal power in MMF for Class 1 and Hazard level 1 (700 nm to
1 050 nm) . 21
Figure A.2 – Maximal power in SMF for Hazard levels 1 and 1M (1 200 nm to
1 400 nm) . 22
Figure A.3 – Maximal power in SMF for Hazard levels 1 and 1M (1 400 nm to
1 650 nm) . 23

Table 1 – Laser wavelength categorization for each specific parameter . 8
Table 2 – Wavelength ranges for fibre optic telecommunication systems . 8
Table 3 – Class 1 and Class 1M power criteria . 9

Table 4 – Measurement aperture diameters and distances for evaluation. 10
Table 5 – Values of 1/η under Conditions 1, 2 and 3 for MMFs . 11
Table 6 – Values of d/r under Conditions 1, 2 and 3 for SMFs . 11
Table 7 – Values of C and T for an extended light source . 13
6 2
Table 8 – Values of the correction factors C and C . 13
4 7
Table 9 – Accessible Emission Limits (AEL) . 13
Table A.1 – Power limits for Hazard levels 1 and 1M. 19
Table A.2 – Related parameters for MMF applications . 20
Table A.3 – AEL values for Classes 1 and 1M and Hazard levels 1 and 1M . 20

– 4 – IEC TR 62150-7:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC ACTIVE COMPONENTS AND DEVICES –
TEST AND MEASUREMENT PROCEDURES –

Part 7: Calculation methodology of laser safety class for
optical transceivers and transmitters

FOREWORD
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IEC TR 62150-7 has been prepared by subcommittee 86C: Fibre optic active components and
devices, of IEC technical committee 86: Fibre optics. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
86C/1934/DTR 86C/1940/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62150 series, published under the general title Fibre optic active
components and devices – Test and measurement procedures, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document 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 – IEC TR 62150-7:2024 © IEC 2024
INTRODUCTION
Laser safety criteria calculations for optical transceivers and transmitters are defined in
IEC 60825-1. However, the calculation methodology in IEC 60825-1 is complicated and covers
a wide range of laser products. This document provides simple calculation guidelines that are
tailored to transceiver and transmitter products for fibre optic telecommunication systems.
The intent of this document is to resolve possible confusion on how to handle the specifications
in IEC 60825-2, which define safety criteria for Optical Fibre Communication Systems (OFCSs).
In IEC 60825-1 the safety categories are called "Class n", but in IEC 60825-2 they are called
"Hazard level n". As single units that are not connected to an OFCS, optical transceivers and
transmitters are components, for which the specifications of IEC 60825-1 are applicable, that is
the safety categories "Class n". However, when optical transceivers and transmitters are
integrated in (i.e. connected to) an Optical Fibre Communication System, the specifications of
IEC 60825-2 apply, which uses the safety categories "Hazard level n". Hence, when the power
levels in an OFCS are examined, the "Hazard level n" categories of IEC 60825-2 apply. For the
same number n, the power limits of "Hazard level n" are usually lower than the power limits of
"Class n". The fact that the power limits for "Class n" and "Hazard level n" are sometimes
different causes considerable confusion in the industry. This document therefore also includes
Hazard level calculations, which are provided in informative Annex A.

FIBRE OPTIC ACTIVE COMPONENTS AND DEVICES –
TEST AND MEASUREMENT PROCEDURES –

Part 7: Calculation methodology of laser safety class for
optical transceivers and transmitters

1 Scope
This part of IEC TR 62150, which is a technical report, provides simple calculation guidelines
for the laser safety class of optical transceivers and transmitters, whose baseline standard is
IEC 60825-1. The calculation methodology for Class 1 and Class 1M safety levels is the main
scope of this document, because most of optical transceivers and transmitters are specified for
these classifications. The calculations and classifications in this document follow IEC 60825-1,
which specifically advises that laser safety classifications be based on tests that consider any
reasonably foreseeable single-fault condition in the application of a transceiver or transmitter.
More information can be found in IEC 60825-1:2014, 5.1.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60825-1:2014, Safety of laser products – Part 1: Equipment classification and requirements
IEC 60825-2, Safety of laser products – Part 2: Safety of optical fibre communication systems
(OFCSs)
NOTE IEC 60825-2:2021 refers to IEC 60825-1:2014 as a normative reference.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60825-1 and
IEC 60825-2 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Calculation methodology
4.1 General
Optical transceivers and transmitters are categorized as optical components, for which the laser
safety specifications are defined in IEC 60825-1. However, when the power levels in an optical
fibre communication system (OFCS) are considered, into which the transceivers or transmitters
are integrated, the safety specifications for OFCSs apply, which are defined in IEC 60825-2.
Both standards are important for transceiver and transmitter laser safety specifications,
depending on the application.
– 8 – IEC TR 62150-7:2024 © IEC 2024
4.2 Wavelength
In IEC 60825-1 and IEC 60825-2, laser wavelengths are categorized into several ranges, as
shown in Table 1, for which important parameters, such as the measurement conditions, the
Accessible Emission Limits (AELs) for Class 1 and Class 1M, and the coefficients C , C and
4 6
C , are defined differently. The wavelength dependence of these parameters reflects the fact
that the effects causing physical damage are wavelength dependent.
Table 1 – Laser wavelength categorization for each specific parameter
Wavelength range Condition 1, 2, 3 AEL for Class 1 / 1M AEL for Class 1 / 1M C C C
4 6 7
(extended)
nm
700 to 1 050  

1 050 to 1 150
  
1 150 to 1 200   
1 200 to 1 400 
1 400 to 4 000  
− − − −
IEC 60825-2:2021
Table 4
Reference IEC 60825-1:2014 IEC 60825-1:2014 IEC 60825-1:2014
document Table 3 Table 4 Table 9
IEC 60825-1:2014
Table 10
When considering optical transceivers for fibre optic telecommunication systems, three
wavelength ranges are of utmost importance. These wavelength ranges are shown in Table 2.
In this document, a case study for these three wavelength ranges is provided to simplify laser
class calculations.
Table 2 – Wavelength ranges for fibre optic telecommunication systems
Wavelength range Optical modulation format Fibre
nm
700 to 1 050 Intensity modulation (on-off keying) Multimode fibre (MMF)
1 200 to 1 400 Intensity modulation (on-off keying) Single-mode fibre (SMF)
Coherent modulation (phase-shift keying)
1 400 to 4 000 Intensity modulation (on-off keying) Single-mode fibre (SMF)
Coherent modulation (phase-shift keying)

4.3 Time base
In IEC 60825-1 and IEC 60825-2, the time base of exposure is one of the principal parameters
for laser class calculations, as shown in IEC 60825-1:2014, Table 3 and Table 4. In the case of
optical transceivers and transmitters for fibre optic communication systems, the power of on-
off-keyed optical signals varies randomly with time but at relatively high speed, whereas the
power of phase-shift-keyed signals, which are often used in coherent transmission systems, is
quasi-continuous. In this document, a time base of more than 100 s is assumed for Table 3 and
Table 4 in IEC 60825-1:2014 to simplify the calculations, considering actual laser product
emission duration.
4.4 Hazard for eye and skin
In case of calculating laser safety specifications, the hazards for eye and skin are both
considered to satisfy the laser safety conditions.

4.5 Class categories
IEC 60825-1 specifies eight levels of safety categories for laser products, which are Class 1
and 1M, Class 1C, Class 2 and 2M, Class 3R, Class 3B, and Class 4. For fibre optic transceivers
and transmitters, Class 1 and 1M are of primary concern in the industry. Therefore, the criteria
of only these two levels and their calculation methodology are reviewed in this document.
"Class 1" limits the optical power to less than or equal to Class 1 power criteria for Condition 1
and Condition 3 (these conditions are described in more detail in 4.6). "Class 1M" limits the
optical power to greater than the Class 1 power and less than the Class 3B power for Condition
1, and less than or equal to the Class 1 power for Condition 3. The requirements are
summarized in Table 3, which shows that the "Class 1 power" is automatically prescribed by
the minimum of the Class1 power limits under Condition 1 and Condition 3, whereas the "Class
1M power" is the minimum of the Class 3B power limit under Condition 1 and the Class 1 power
limit under Condition 3.
Table 3 – Class 1 and Class 1M power criteria
Condition 1 Condition 2 Condition 3
Class 1 power Power ≤ Class 1 - Power ≤ Class 1
Class 1M power Class 1 < power < Class 3B - Power ≤ Class 1

4.6 Measurement conditions 1, 2, and 3
Three combinations of measurement aperture stop and distance from source to aperture for
evaluation are specified in IEC 60825-1 and IEC 60825-2. Figure 1 shows a graphic illustration
of the measurement setup.
Figure 1 – Graphic illustration of distance to source and apertur
...