SIST EN IEC 62007-2:2025

SLOVENSKI STANDARD
01-november-2025
Nadomešča:
SIST EN 62007-2:2009
Polprevodniške optoelektronske naprave za uporabo v sistemih z optičnimi vlakni
- 2. del: Merilne metode (IEC 62007-2:2025)
Semiconductor optoelectronic devices for fibre optic system applications - Part 2:
Measuring methods (IEC 62007-2:2025)
Optoelektronische Halbleiterbauelemente für Anwendungen in Lichtwellenleitersystemen
- Teil 2: Messverfahren (IEC 62007-2:2025)
Dispositifs optoélectroniques à semiconducteurs pour application dans les systèmes
fibroniques - Partie 2: Méthodes de mesure (IEC 62007-2:2025)
Ta slovenski standard je istoveten z: EN IEC 62007-2:2025
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
33.180.01 Sistemi z optičnimi vlakni na Fibre optic systems in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62007-2

NORME EUROPÉENNE
EUROPÄISCHE NORM September 2025
ICS 31.080.01; 31.260; 33.180.01 Supersedes EN 62007-2:2009
English Version
Semiconductor optoelectronic devices for fibre optic system
applications - Part 2: Measuring methods
(IEC 62007-2:2025)
Dispositifs optoélectroniques à semiconducteurs pour Optoelektronische Halbleiterbauelemente für Anwendungen
application dans les systèmes fibroniques - Partie 2: in Lichtwellenleitersystemen - Teil 2: Messverfahren
Méthodes de mesure (IEC 62007-2:2025)
(IEC 62007-2:2025)
This European Standard was approved by CENELEC on 2025-08-15. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62007-2:2025 E

European foreword
The text of document 86C/1975/FDIS, future edition 3 of IEC 62007-2, prepared by SC 86C "Fibre
optic systems, sensing and active devices" of IEC/TC 86 "Fibre optics" was submitted to the IEC-
CENELEC parallel vote and approved by CENELEC as EN IEC 62007-2:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-09-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-09-30
document have to be withdrawn
This document supersedes EN 62007-2:2009 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62007-2:2025 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60793 (series) NOTE Approved as EN IEC 60793 (series)
IEC 60794 (series) NOTE Approved as EN IEC 60794 (series)
IEC 61300 (series) NOTE Approved as EN 61300 (series)
IEC 61315 NOTE Approved as EN IEC 61315
IEC 61753 (series) NOTE Approved as EN 61753 (series)
IEC 61754 (series) NOTE Approved as EN 61754 (series)
IEC 61755 (series) NOTE Approved as EN IEC 61755 (series)
ISO 1101 NOTE Approved as EN ISO 1101

IEC 62007-2 ®
Edition 3.0 2025-07
INTERNATIONAL
STANDARD
Semiconductor optoelectronic devices for fibre optic system applications –
Part 2: Measuring methods
ICS 31.080.01; 31.260; 33.180.01 ISBN 978-2-8327-0572-8

IEC 62007-2:2025-07(en)
IEC 62007-2:2025 © IEC 2025
CONTENTS
FOREWORD. 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 7
4 Measuring methods for photoemitters . 7
4.1 Outline of the measuring methods . 7
4.2 Radiant power and forward current of LEDs and LDs with or without optical
fibre pigtails . 8
4.3 Small signal cut-off frequency of LEDs and LDs with or without optical fibre
pigtails . 9
4.4 Threshold current of LDs with or without optical fibre pigtails . 10
4.5 Relative intensity noise of LEDs and LDs with or without optical fibre pigtails . 11
4.6 S parameter of LEDs, LDs, and LD modules with or without optical fibre
pigtails . 12
4.7 Tracking error for LD modules with optical fibre pigtails, with or without
cooler . 14
4.8 Spectral linewidth of LDs with or without optical fibre pigtails . 17
4.9 Modulation current at 1 dB efficacy compression of LEDs . 19
4.10 Differential efficiency of an LD module or an LD with or without optical fibre
pigtail. 21
4.11 Differential (forward) resistance of an LD with or without optical fibre pigtail . 23
5 Measuring methods for receivers . 24
5.1 Outline of the measuring methods . 24
5.2 Noise of a PIN photodiode . 25
5.3 Excess noise factor of an APD with or without optical fibre pigtails . 27
5.4 Small-signal cut-off frequency of a photodiode with or without optical fibre
pigtails . 29
5.5 Multiplication factor of an APD with or without an optical fibre pigtail . 30
5.6 Responsivity of a PIN-TIA module . 31
5.7 Frequency response flatness of a PIN-TIA module . 33
5.8 Output noise power (spectral) density of a PIN-TIA module . 34
5.9 Low frequency output noise power (spectral) density and corner frequency of
a PIN-TIA module . 36
5.10 Minimum detectable power of PIN-TIA module . 38
Bibliography . 40

Figure 1 – Equipment setup for measuring radiant power and forward current of LEDs
or LDs . 8
Figure 2 – Circuit diagram for measuring f of LEDs or LDs . 9
c
Figure 3 – Circuit diagram for measuring threshold current of LDs . 10
Figure 4 – Graph to determine threshold current of LDs . 11
Figure 5 – Circuit diagram for measuring RIN of LEDs or LDs . 11
Figure 6 – Circuit diagram for measuring the S parameter of LEDs, LDs, or LD
modules . 13
IEC 62007-2:2025 © IEC 2025
Figure 7 – Circuit diagrams for LDs with cathode or anode connected to package . 15
Figure 8 – Output radiant power versus time . 16
Figure 9 – Output radiant power versus case temperature . 17
Figure 10 – Equipment setup for measuring the spectral linewidth of LDs . 18
Figure 11 – Circuit diagram for measuring 1 dB efficacy compression of LEDs . 20
Figure 12 – Plot of 20 × log(V ) versus 20 × log(I ) . 21
2 1
Figure 13 – Circuit diagram for measuring differential efficiency of LDs . 22
Figure 14 – Current waveform for differential efficiency measurement . 22
Figure 15 – Circuit diagram for measuring differential resistance of LDs . 23
Figure 16 – Current waveform for differential resistance . 24
Figure 17 – Circuit diagram for measuring noise of a PIN photoreceiver . 25
Figure 18 – Circuit diagram for measuring noise with synchronous detection . 26
Figure 19 – Circuit diagram for measuring excess noise of an APD . 27
Figure 20 – Circuit diagram for measuring f of a photodiode . 29
c
Figure 21 – Circuit diagram for measuring multiplication factor of an APD . 30
Figure 22 – Graph showing measurement of I and I . 31
R1 R2
Figure 23 – Circuit diagram for measuring responsivity of a PIN-TIA module . 32
Figure 24 – Circuit diagram for measuring frequency response flatness of a PIN-TIA
module . 33
Figure 25 – Circuit diagram for measuring output noise power (spectral) density of a
PIN-TIA module under matched output conditions . 35
Figure 26 – Circuit diagram for measuring output noise power (spectral) density of a
non-irradiated PIN-TIA module in the low frequency region . 36
Figure 27 – Graph of V versus frequency . 38
m
Figure 28 – Circuit diagram for measuring minimum detectable power of a PIN-TIA
module . 39

IEC 62007-2:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Semiconductor optoelectronic devices
for fibre optic system applications -
Part 2: Measuring methods
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 62007-2 has been prepared by subcommittee 86C: Fibre optic systems, sensing and active
devices, of IEC technical committee 86: Fibre optics. It is an International Standard.
This third edition cancels and replaces the second edition published in 2009. This edition
constitutes a technical revision.
IEC 62007-2:2025 © IEC 2025
This edition includes the following significant technical changes with respect to the previous
edition:
a) Modification of the definition of “optical fibre pigtail” in 3.1.3;
b) Correction of an error in Formula (1) for relative intensity noise;
c) Correction of an error in Formula (5);
d) Correction of errors in the title of Figure 11 and the text of 4.9 (replaced "LD" with "LED");
e) Clarification of how to calculate the 1 dB compression in 4.9;
f) Corrections of the circuit diagrams in Figure 2, Figure 5, Figure 11, Figure 17, Figure 18,
Figure 19, Figure 20, and Figure 21;
g) Clarification of the measurement setup in 5.10 (Figure 28).
The text of this International Standard is based on the following documents:
Draft Report on voting
86C/1975/FDIS 86C/1985/RVD
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 International Standard 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 of the IEC 62007 series can be found, under the general title Semiconductor
optoelectronic devices for fibre optic system applications, 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.
IEC 62007-2:2025 © IEC 2025
INTRODUCTION
Semiconductor optical signal transmitters and receivers play important roles in optical
communication networks. This document covers the measurement procedures for evaluating
their optical and electrical properties that are important for applications in digital communication
systems. These properties are essential for specifying the performance of these devices.

IEC 62007-2:2025 © IEC 2025
1 Scope
This part of IEC 62007 specifies measuring methods for characterizing semiconductor
optoelectronic devices that are used in the field of fibre optic digital communication systems
and subsystems.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions 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
3.1.1
PIN photodiode
photodiode with a large intrinsic region sandwiched between P- and N-doped semiconducting
regions used for the detection of optical radiation
[SOURCE: IEC 60050-731:1991, 731-06-29, modified – the note was removed.]
3.1.2
avalanche photodiode
APD
photodiode operating with a bias voltage such that the primary photocurrent undergoes
amplification by cumulative multiplication of charge carriers
[SOURCE: IEC 60050-731:1991, 731-06-30, modified – the note was removed.]
3.1.3
optical fibre pigtail
short length of optical fibre, usually permanently attached to a component and intended to
facilitate jointing between that component and another optical fibre or component
[SOURCE: IEC 60050-731:1991, 731-05-08, modified – the note was removed.]
IEC 62007-2:2025 © IEC 2025
3.2 Abbreviated terms
AC alternating current
AL adjustable line
APD avalanche photodiode
BER bit-error ratio
DC direct current
LED light emitting diode
LD laser diode
NRZ non-return to zero
PD photodetector
RF radio frequency
RIN relative intensity noise
RMS root mean square
RZ return to zero
TIA transimpedance amplifier
TL test line
4 Measuring methods for photoemitters
4.1 Outline of the measuring methods
Light emitting diodes (LEDs) and laser diodes (LDs) have important opto-electronic properties,
which shall be specified when they are used in optical communication systems. The
measurement methods for characterizing these opto-electronic properties are described in 4.2
to 4.11, where each subclause covers the following topics:
a) Purpose,
b) One of the following items:
• Measurement equipment,
• Equipment setup,
• Circuit diagram,
• Circuit design and current waveform for measurement.
c) Equipment or circuit description and requirements,
d) Precautions to be observed,
e) Measurement procedures,
f) Specified conditions.
If a device is equipped with an optical fibre pigtail, all optical fibres and cables defined in the
IEC 60793 and IEC 60794 series are applicable. If an optical fibre pigtail is to be terminated
with an optical connector, all optical connectors defined in the IEC 61754 and IEC 61755 series
are applicable.
IEC 62007-2:2025 © IEC 2025
4.2 Radiant power and forward current of LEDs and LDs with or without optical fibre
pigtails
a) Purpose
To measure the radiant power Φ and the forward current I of LEDs and LDs, with or
e F
without optical fibre pigtails, under specified conditions.
b) Measurement equipment
Figure 1 shows the equipment setup for measuring the radiant power and forward current
of LEDs and LDs.
Figure 1 – Equipment setup for measuring radiant power
and forward current of LEDs or LDs
c) Equipment description and requirements
The radiation emitted by the device is subjected to multiple reflections from the walls of the
integrating sphere; this leads to a uniform irradiance of the surface proportional to the
emitted flux. A detector located in the walls of the sphere measures this irradiance. An
opaque screen shields the detector from the direct radiation of the device being measured.
d) Precautions to be observed
The device being measured, the screen, and the apertures shall be small compared to the
sphere surface.
The inner surface of the sphere and screen shall have a diffusing coating with a high uniform
reflection coefficient (0,8 minimum).
The sphere and detector assembly shall be calibrated.
The measured values for radiant power and forward current shall be corrected for variations
in peak-emission wavelength and radiation flux.
When the radiation emitted by the device being measured is pulsed, the detector shall time-
average the measured radiation.
e) Measurement procedure
The emitting device is positioned at the entrance of the integrating sphere, so that no direct
radiation will reach the detector.
For measurements of radiant power, the specified forward current I is applied to the device,
F
and the radiant power is measured by the photodetector.
For measurements of forward current, the current applied to the device is increased until
the specified radiant power Φ is achieved. The value of this current is recorded.
e
IEC 62007-2:2025 © IEC 2025
f) Specified conditions
• Ambient or case temperature.
• Radiant power (when measuring forward current).
• Forward current (when measuring radiant power).
4.3 Small signal cut-off frequency of LEDs and LDs with or without optical fibre
pigtails
a) Purpose
To measure the small signal cut-off frequency f of LEDs and LDs with or without optical
c
fibre pigtails, under specified conditions.
b) Circuit diagram
of LEDs and LDs.
Figure 2 shows a circuit diagram for measuring f
c
Key
D device being measured
G AC generator with adjustable frequency
G DC generator
PD photodetector
M measuring instrument for AC radiant power
C coupling capacitor
Figure 2 – Circuit diagram for measuring f of LEDs or LDs
c
c) Equipment description and requirements
No requirements for this item.
d) Precautions to be observed
The radiant power reflected back into the laser diode shall be minimized to avoid modulation
distortions, which could affect the accuracy of the measurement. The photodetector shall
have a frequency response greater than f .
c
e) Measurement procedure
For LEDs, the specified direct forward current or the direct forward current required to obtain
the specified radiant power is applied to the device being measured.
For laser diodes, the forward current is adjusted to a value which is equal to the continuous
forward current above threshold or which generates a specified radiant power.
The forward current is modulated using generator G at a low frequency f (less than f /100),
1 l c
and the AC radiant power is measured by instrument M (see Figure 2).
Keeping the modulation level constant, the modulation frequency is increased until the
output radiant power measured by M is reduced to 50 % of the value obtained at f .
l
This frequency is the small-signal cut-off frequency f .
c
IEC 62007-2:2025 © IEC 2025
f) Specified conditions
For light-emitting diodes (LED):
• ambient or case temperature;
• DC forward current or radiant power.
For the laser diodes (LD):
• ambient, case, or submount temperature;
• radiant power or difference between applied DC forward current and threshold
current of LD.
4.4 Threshold current of LDs with or without optical fibre pigtails
a) Purpose
To measure the threshold current of a laser diode, with or without optical fibre pigtails.
b) Circuit diagram
Figure 3 shows a circuit diagram for measuring threshold current of a laser diode.

Key
D device being measured
PD photodetector measuring incident radiant power
A ammeter
G generator (DC or pulsed current)
Figure 3 – Circuit diagram for measuring threshold current of LDs
c) Circuit description and requirements
For pulse measurement, the current generator, G, shall provide current pulses of the
required amplitude, duration and repetition rate.
d) Precautions to be observed
Radiant power reflected back into the laser diode shall be minimized. The limiting values of
and Φ ) shall not be overstepped.
the laser diode (I
F e
e) Measurement procedure
A forward current is applied to the diode and the relation between the incident radiant power
from the diode and the forward current is recorded.
The forward current at which the second derivative of the recorded curve showing incident
radiant power versus the forward current has its first maximum is determined (see Figure 4).
The forward current at this point is the threshold current I .
TH
f) Specified conditions
• Ambient, case or submount temperature.
• For pulse measurement, repetition frequency and pulse duration of the forward current.
Figure 4 illustrates how to determine the threshold current of LDs.
IEC 62007-2:2025 © IEC 2025
Key
I threshold current
TH
Figure 4 – Graph to determine threshold current of LDs
4.5 Relative intensity noise of LEDs and LDs with or without optical fibre pigtails
a) Purpose
To measure the relative intensity noise (RIN) of LEDs and LDs, with or without optical fibre
pigtails, under specified conditions.
b) Circuit diagram
Figure 5 shows a circuit diagram for measuring RIN of LEDs and LDs.

Key
G DC current generator
D device being measured
L lens system
forward current
I
F
PD photodetector
R load resistance
L
I reverse current of the photodetector under optical radiation
R(H)
G DC generator for PD bias voltage
AMP AC amplifier with gain G
F electrical filter with centre frequency f and equivalent noise bandwidth Δf
0 N
M measuring instrument (e.g. electrical power level meter)
C capacitance of bypass capacitor for DC voltage generator G
B 2
Figure 5 – Circuit diagram for measuring RIN of LEDs or LDs
IEC 62007-2:2025 © IEC 2025
c) Circuit description and requirements
No requirements for this item.
d) Precautions to be observed
Radiant power reflected back into the laser diode shall be minimized to avoid distortions
affecting accuracy of the measurements.
e) Measurement procedure
A DC current corresponding to the specified radiant power Φ is applied to the device. The
e
noise power N is measured by the measuring instrument M, and the reverse photo current
t
I of the photodetector is measured simultaneously under optical radiation.
R(H)
The LD or LED being measured is replaced by an optically broadband light source that emits
radiation in the same wavelength range as the LD or LED being measured.
The irradiating power of the broadband light source is adjusted to obtain the same reverse
current I of the photodetector as previously measured with the LED or LD. The
R(H)
corresponding noise power N , which consists of the photodetector shot-noise and the
d
electrical amplifier noise, is then measured by instrument M.
The RIN is expressed in dB/Hz and calculated from Formula (1).

NN−
td

Rf 10×log
( ) (1)
RIN 0 10

R ××G Δf × I
L N R(H)

where
f is the centre frequency of the electrical filter, expressed in Hz;
G is the gain of the electrical amplifier, expressed in linear units;
I is the reverse current of the photodetector, expressed in A;
R(H)
N is the noise power measured with the broadband light source, expressed in W;
d
N is the noise power measured with the LED or LD under test, expressed in W;
t
R is the gain of the load resistance of the PD, expressed in Ω;
L
Δf is the equivalent noise bandwidth of the electrical filter, expressed in Hz.
N
f) Specified conditions
• Ambient, case, or submount temperature of the LED or LD.
• Radiant power.
• Centre frequency and equivalent noise bandwidth of the electrical filter.
4.6 S parameter of LEDs, LDs, and LD modules with or without optical fibre pigtails
a) Purpose
To measure the real and imaginary parts (or modulus and phase) of the electrical input
characteristic of a device at a specified radiant power level and at a specified frequency.
The S parameter is the ratio of the (complex-valued) high-frequency voltage V reflected
11 rl
from the device to the high-frequency voltage V incident on the device electrical input port,
il
as shown in Formula (2).
V
rl
S =
(2)
V
il
=
IEC 62007-2:2025 © IEC 2025
An equivalent formula using complex impedances instead of complex voltages is given by
Formula (3).
ΖZ−
1 0
=
S
(3)
ZZ+
where
Z is the input impedance of the device being measured, expressed in Ω;
Z is the characteristic impedance of the measurement equipment, expressed in Ω.
b) Circuit diagram
Figure 6 shows the circuit diagram for measuring the S parameter of LEDs, LDs, and
LD modules.
Key
G RF generator
T bias-T circuit
CS DC source
DC1 directional coupler in forward direction
DC2 directional coupler in reverse direction
AL adjustable transmission line
NA network analyser
D device being measured (LED, LD, or LD module)
PM radiant power meter
TL test transmission line
Figure 6 – Circuit diagram for measuring the S parameter
of LEDs, LDs, or LD modules
c) Equipment description and requirements
No requirements for this item.
d) Precautions to be observed
The characteristic impedances of the transmission lines, generator, attenuators, device
measuring socket, bias-T circuit, and loads shall be matched to a common impedance
(usually 50 Ω) over the specified frequency range.
The RF power delivered by the RF generator shall be low enough to allow for linear
operation of the device being measured.
Ensure that the optical ports of the device D and the power meter PM are aligned.
IEC 62007-2:2025 © IEC 2025
e) Measurement procedure
• Calibration
• The adjustable line (AL) shall balance the test line (TL). This can be achieved by
performing the following procedure.
• A short circuit is connected to the electrical input line at the location of the device being
measured.
• The AC signal frequency is scanned around the specified frequency f, and the length of
the adjustable line is varied until a single point S is obtained on the Smith chart
(modulus equals 1 and phase equals 180°).
• Measurement
• The short circuit used in the calibration procedure is replaced by the device D. The
operating conditions of the device being measured are applied as specified (Φ and
e
T , T , or T ), and the value of S corresponding to the reflection coefficient of
case amb sub 11
the device D is obtained from the network analyser NA.
f) Specified conditions
• Ambient, case or submount temperature.
• Supply and drive conditions: Φ or I , ΔI , f, and modulation depth m.
e F F
4.7 Tracking error for LD modules with optical fibre pigtails, with or without cooler
a) Purpose
To measure the maximum variations of the tracking ratio between the fibre output radiant
power and the monitor diode photocurrent of a laser module over a specified temperature
range.
b) Circuit diagram
Figure 7 (a) shows the circuit diagram for the case where the laser cathode is connected to
the LD package, and Figure 7 (b) shows the same for the case where the laser anode is
connected to the LD package.
IEC 62007-2:2025 © IEC 2025
a) Laser diode with laser cathode connected to package

b) Laser diode with laser anode connected to package
Key
D device being measured
D monitor diode
M
PD calibrated photodetector
G DC current source, monitored through negative feedback by the photocurrent delivered by the monitor
photodiode
G DC voltage source
R load resistance
L
V DC voltmeter
DM
V DC voltmeter
R
D laser diode
L
Figure 7 – Circuit diagrams for LDs with cathode or anode connected to package
c) Equipment description and requirements
No requirements for this item.
IEC 62007-2:2025 © IEC 2025
d) Precautions to be observed
The optical radiant power reflected back to the laser diode shall be minimized.
The case temperature of the LD should be varied slowly enough to ensure that thermal
equilibrium takes place inside the module and, in the case of a module with cooler, that the
specified submount temperature T is stabilized.
sub
e) Measurement procedure
At each measuring point, the DC current from source G is adjusted until the monitor photo-
current is equal to the value obtained with the specified optical radiation power at 25 °C.
The case temperature is scanned over the specified range and the plot of the output radiant
power is recorded either versus time, as shown in Figure 8, or versus case temperature, as
shown in Figure 9.
The tracking errors expressed in percent are given by Formula (4) and Formula (5):
ΦΦ−

e min
e25 C
E ×100 (%)
(4)
R1
Φ

e25 C
Φ −Φ

e max
e25 C
E ×100 (%)
(5)
R2
Φ

e25 C
where
Փ is the minimal radiant power recorded during the temperature scan, expressed
e min
in W;
Փ is the maximal radiant power recorded during the scan, expressed in W;
e max
Փ is the radiant power measured at 25 °C, expressed in W.
e 25 °C
Figure 8 – Output radiant power versus time
=
=
IEC 62007-2:2025 © IEC 2025
Figure 9 – Output radiant power versus case temperature
f) Specified conditions
• Փ at 25 °C.
e
• Case or ambient temperature range T and T , or T and T .
case min case max amb min amb max
• Submount temperature T , where appropriate.
sub
• Bias voltage V of monitor photodiode D .
R M
4.8 Spectral linewidth of LDs with or without optical fibre pigtails
a) Purpose
To measure the spectral linewidth of LDs with or without optical fibre pigtails.
b) Equipment setup
Figure 10 shows the equipment setup and circuit diagram for measuring the spectral
linewidth of LDs.
IEC 62007-2:2025 © IEC 2025
Key
G DC current source
D device being measured
L1, L2, L3 lenses
OI optical isolator
AO acousto-optic modulator
AO/D driver for acousto-optic modulator
M mirror
P1 polarization adjustment device
F1, F2, F3 single mode fibres
OC optical coupler
PD photodetector
AMP amplifier
SA spectrum analyser
Figure 10 – Equipment setup for measuring the spectral linewidth of LDs
c) Equipment description and requirements
No requirements for this item.
d) Precautions to be observed
Radiation power reflected back into the laser diode shall be minimized.
Length of F3 should be sufficiently long to obtain a greater resolution than the spectral
linewidth of the device being measured D.
Modulation frequency should be higher than the spectral linewidth of the device D.
The specified DC current should be sufficiently stabilized so as not to broaden the measured
linewidth of the device D.
NOTE The length of fibre F3 determines the frequency resolution δf of the linewidth measurement, which is
given by:
0,75 c
δf =
πLn
IEC 62007-2:2025 © IEC 2025
where
c is the velocity of light, expressed in m/s;
L is the length of fibre F3, expressed in m;
n is the refractive index of fibre F3.
e) Measurement procedure
The specified DC current above threshold (ΔI ) or the forward current corresponding to a
F
specified radiant power (Փ ) is applied to the device D being measured.
e
The optical port of the device D is aligned to get maximum radiant power into the optical
fibres F1 and F3.
A peak corresponding to the modulation frequency of the acousto-optic modulator AO is
observed on the spectrum analyser. The polarization adjuster P1 is rotated until the peak is
maximal (corresponding to maximal interference between the radiation emerging from fibres
F1 and F3). The full width at half maximum of the observed peak is measured. The measured
value is twice the spectral linewidth of the device D.
f) Specified conditions
• Ambient, case, or submount temperature.
• Forward current above threshold ΔI or radiant power Փ .
F e
4.9 Modulation current at 1 dB efficacy compression of LEDs
a) Purpose
To measure the modulation current at 1 dB efficacy compression, denoted I , at a
F(1 dB)
specified modulation frequency and radiant output power.
b) Circuit diagram
Figure 11 shows the circuit diagram for measuring 1 dB efficacy compression of LEDs.
IEC 62007-2:2025 © IEC 2025
Key
D device being measured
G sine wave signal source
C capacitance of coupling capacitor
P power supply to provide the specified radiant power Փ to D
1 e
V AC voltmeter or broadband voltage measuring equipment for measuring V and V
1 2
R load resistor for matching the specified electrical impedance of D
L1
D optical signal detector
T
R load resistor for matching the specified electrical impedance of D
L2 T
P power supply to provide the operating voltage to D
2 T
F band-pass filter centre frequency matched to the frequency f of the sine wave signal source
A amplifier
C capacitance of bypass capacitor for DC voltage supply P
B 2
V modulation voltage
V detected signal voltage
Figure 11 – Circuit diagram for measuring 1 dB efficacy compression of LEDs
c) Equipment description and requirements
No requirements for this item.
d) Precautions to be observed
The optical output port of the device being measured shall be coupled as best as possible
to input port of the optical signal detector.

e) Measurement procedure
Couple the optical output of device D from the optical port to the detector D . Apply the
T
supply current from power supply P to the appropriate connections of D to generate the
specified output radiant power Փ from the output port of device D. Apply modulation current
e
from signal generator G at the specified modulation frequency. Record the detected signal
voltage V and the modulation voltage V while the modulation current is increased. The
2 1
modulation current I (I = V /R ) is determined from V using the value of R . Identify the
1 1 1 L1 1 L1
region for which there is a linear relationship between log(V ) and log(I ). Record the value
2 1
of I at which 20 × log(V ) is 1 dB below the value resulting from the projected linear region,
1 2
as shown in Figure 12. This value of I is the modulation current at 1 dB efficacy
compression, i.e. I .
F(1 dB)
NOTE 1 The value of V expressed in dB is given by 20 × log(V ), where V is expressed in V.
2 2 2
NOTE 2 The functions of the filter F and AC voltmeter V are typically incorporated in RF spectrum analyser
instruments. Such instruments can be used in place of the individual circuit elements shown in the circuit
description. With this substitution, the measured quantities are AC signal powers instead of signal amplitudes.
IEC 62007-2:2025 © IEC 2025
Figure 12 shows a plot of 20 × log(V ) versus 20 × log(I ), where V is expressed in V and
2 1 2
I is expressed in A.
Figure 12 – Plot of 20 × log(V ) versus 20 × log(I )
2 1
f) Specified conditions
• Ambient or case temperature, T or T .
amb case
• Load resistances R and R .
L1 L2
• Peak-emission wavelength and spectral radiation bandwidth of the light source (λ , Δλ).
p
• Radiant power Փ .
e
• Modulation frequency f.
4.10 Differential efficiency of an LD module or an LD with or without optical fibre
pigtail
a) Purpose
To measure the differential efficiency η of LD modules or LDs with or without optical fibre
d
pigtail.
b) Circuit diagram and current waveform
Figure 13 shows the circuit diagram for measuring differential efficiency of an LD and
Figure 14 shows the current waveform for differential efficiency measurement.
IEC 62007-2:2025 © IEC 2025
Key
D device being measured I forward current
F
PG current step generator V voltmete
...