SIST EN 62007-2:2009

SLOVENSKI STANDARD
01-maj-2009
1DGRPHãþD
SIST EN 62007-2:2002
3ROSUHYRGQLãNHRSWRHOHNWURQVNHQDSUDYH]DXSRUDERYVLVWHPLK]RSWLþQLPLYODNQL
GHO0HULOQHPHWRGH,(&
Semiconductor optoelectronic devices for fibre optic system applications - Part 2:
Measuring methods (IEC 62007-2:2009)
Optoelektronische Halbleiterbauelemente für Anwendungen in Lichtwellenleitersystemen
- Teil 2: Messverfahren (IEC 62007-2:2009)
Dispositifs optoélectroniques à semiconducteurs pour application dans les systèmes à
fibres optiques - Partie 2: Méthodes de mesure (CEI 62007-2:2009)
Ta slovenski standard je istoveten z: EN 62007-2:2009
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
33.180.01 6LVWHPL]RSWLþQLPLYODNQLQD Fibre optic systems in
VSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62007-2
NORME EUROPÉENNE
March 2009
EUROPÄISCHE NORM
ICS 31.080.01; 31.260; 33.180.01 Supersedes EN 62007-2:2000

English version
Semiconductor optoelectronic devices
for fibre optic system applications -
Part 2: Measuring methods
(IEC 62007-2:2009)
Dispositifs optoélectroniques  Optoelektronische Halbleiterbauelemente
à semiconducteurs pour application für Anwendungen
dans les systèmes à fibres optiques - in Lichtwellenleitersystemen -
Partie 2: Méthodes de mesure Teil 2: Messverfahren
(CEI 62007-2:2009) (IEC 62007-2:2009)

This European Standard was approved by CENELEC on 2009-02-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: avenue Marnix 17, B - 1000 Brussels

© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62007-2:2009 E
Foreword
The text of document 86C/868/FDIS, future edition 2 of IEC 62007-2, prepared by SC 86C, Fibre optic
systems and active devices, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote
and was approved by CENELEC as EN 62007-2 on 2009-02-01.
This European Standard supersedes EN 62007-2:2000.
– descriptions related to analogue characteristics have been removed;
– some definitions and terms have been revised for harmonisation with other standards originating from
SC 86C.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-11-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2012-02-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62007-2:2009 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 standards indicated:
IEC 61300 NOTE  Harmonized in EN 61300 series (not modified).
IEC 61315 NOTE  Harmonized as EN 61315:2006 (not modified).
ISO 1101 NOTE  Harmonized as EN ISO 1101:2005 (not modified).
__________
- 3 - EN 62007-2:2009
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60050-731 1991 International Electrotechnical Vocabulary - -
(IEV) -
Chapter 731: Optical fibre communication

IEC 60793 (mod) Series Optical fibres EN 60793 Series

IEC 60794 Series Optical fibre cables EN 60794 Series

IEC 60874 Series Connectors for optical fibres and cables EN 60874 Series

IEC 62007-2
Edition 2.0 2009-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Semiconductor optoelectronic devices for fibre optic system applications –
Part 2: Measuring methods
Dispositifs optoélectroniques à semiconducteurs pour application dans les
systèmes à fibres optiques –
Partie 2: Méthodes de mesure
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
W
CODE PRIX
ICS 31.080.01; 31.260; 33.180.01 ISBN 2-8318-1023-6
– 2 – 62007-2 © IEC:2009
CONTENTS
FOREWORD.0H4
INTRODUCTION.1H6
1 Scope.2H7
2 Normative references .3H7
3 Terms, definitions and abbreviations .4H7
3.1 Terms and definitions .5H7
3.2 Abbreviations .6H8
4 Measuring methods for photoemitters .7H8
4.1 Outline of the measuring methods .8H8
4.2 Radiant power or forward current of LEDs and LDs with or without optical
fibre pigtails .9H8
4.3 Small signal cut-off frequency (f ) of LEDs and LDs with or without optical
c
fibre pigtails .10H9
4.4 Threshold current of LDs with or without optical fibre pigtails .11H10
4.5 Relative intensity noise of LEDs and LDs with or without optical fibre pigtails.12H12
4.6 S parameter of LEDs, LDs and LD modules with or without optical fibre
pigtails .13H13
4.7 Tracking error for LD modules with optical fibre pigtails, with or without
cooler.14H15
4.8 Spectral linewidth of LDs with or without optical fibre pigtails .15H17
4.9 Modulation current at 1 dB efficacy compression (I ) of LEDs .16H18
F (1 dB)
4.10 Differential efficiency (η ) of a LD with or without pigtail and an LD module .17H20
d
4.11 Differential (forward) resistance r of an LD with or without pigtail .18H22
d
5 Measuring methods for receivers.19H23
5.1 Outline of the measuring methods .20H23
5.2 Noise of a PIN photodiode.21H23
5.3 Excess noise factor of an APD with or without optical fibre pigtails.22H25
5.4 Small-signal cut-off frequency of a photodiode with or without optical fibre
pigtails .23H27
5.5 Multiplication factor of an APD with or without optical fibre pigtails .24H28
5.6 Responsivity of a PIN-TIA module .25H30
5.7 Frequency response flatness (ΔS/S) of a PIN-TIA module .26H32
5.8 Output noise power (spectral) density P of a PIN-TIA module.27H33
λ
no,
5.9 Low frequency output noise power (spectral) density (P ) and corner
,λ,
no LF
frequency (f ) of a PIN-TIA module .28H35
cor
5.10 Minimum detectable power of PIN-TIA module .29H36
Bibliography.30H38

Figure 1 – Equipment setup for measuring radiant power and forward current of LEDs
and LDs .31H8
Figure 2 – Circuit diagram for measuring small-signal cut-off frequency LEDs and LDs .32H10
Figure 3 – Circuit diagram for measuring threshold current of a LD.33H11
Figure 4 – Graph to determine threshold current of lasers.34H11
Figure 5 – Circuit diagram for measuring RIN of LEDs and LDs .35H12
Figure 6 – Circuit diagram for measuring the S parameter LEDs, LDs and LD
modules.36H14

62007-2 © IEC:2009 – 3 –
Figure 7– Cathode and anode connected to the package of a LD.37H15
Figure 8 – Output radiant power versus time.38H16
Figure 9 – Output radiant power versus case temperature .39H16
Figure 10 – Circuit diagram for measuring linewidth of LDs.40H17
Figure 11 – Circuit diagram for measuring 1 dB efficacy compression of LDs.41H19
Figure 12 – Plot of log V versus log I .42H20
2 1
Figure 13 – Circuit diagram for measuring differential efficiency of a LD .43H21
Figure 14 – Current waveform for differential efficiency measurement .44H21
Figure 15 – Circuit diagram for measuring differential resistance .45H22
Figure 16 – Current waveform for differential resistance .46H23
Figure 17 – Circuit diagram for measuring noise of a PIN photoreceiver .47H24
Figure 18 – Circuit diagram for measuring noise with synchronous detection .48H25
Figure 19 – Circuit diagram for measuring excess noise of an APD.49H26
Figure 20 – Circuit diagram for measuring small-signal cut-off wavelength of a
photodiode.50H28
Figure 21 – Circuit diagram for measuring multiplication factor of an APD .51H29
Figure 22 – Graph showing measurement of I and I .52H30

R1 R2
Figure 23 – Circuit diagram for measuring responsivity of a PIN-TIA module .53H31
Figure 24 – Circuit diagram for measuring frequency response flatness of a PIN-TIA
module.54H32
Figure 25 – Circuit diagram for measuring output noise power (spectral) density of a
PIN-TIA module under matched output conditions.55H34
Figure 26 – Circuit diagram for measuring output noise power (spectral) density of a
non-irradiated PIN-TIA module in the low frequency region.56H35
Figure 27 – Graph of V versus frequency.57H36
m
Figure 28 – Circuit diagram for measuring minimum detectable power of a PIN-TIA
module at a specified bit-error rate (BER) or carrier-to-noise ratio (C/N) .58H37

– 4 – 62007-2 © IEC:2009
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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) 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 62007-2 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
This second edition cancels and replaces the first edition published in 1997, and its
amendment 1(1998). It is a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) descriptions related to analogue characteristics have been removed;
b) some definitions and terms have been revised for harmonisation with other standards
originating from SC 86C.
62007-2 © IEC:2009 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
86C/868/FDIS 86C/870/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 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 publication will remain unchanged until
the maintenance result 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 – 62007-2 © IEC:2009
INTRODUCTION
Semiconductor optical signal transmitters and receivers play important roles in optical
information networks. This standard covers the measurement procedures for their optical and
electrical properties that are intended for digital communication systems. These properties are
essential to specify their performance.

62007-2 © IEC:2009 – 7 –
SEMICONDUCTOR OPTOELECTRONIC DEVICES
FOR FIBRE OPTIC SYSTEM APPLICATIONS –

Part 2: Measuring methods
1 Scope
This part of IEC 62007 describes the measuring methods applicable to the semiconductor
optoelectronic devices to be used in the field of fibre optic digital communication systems and
subsystems.
All optical fibres and cables that are defined in IEC 60793 series, IEC 60794 series are
applicable. All optical connectors that are defined in IEC 60874 series are applicable, if a
pigtail is to be terminated with an optical connector.
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 60050-731:1991, International Electrotechnical Vocabulary – Chapter 731: Optical fibre
communication
IEC 60793 (all parts), Optical fibres
IEC 60794 (all parts), Optical fibre cables
IEC 60874 (all parts), Connectors for optical fibres and cables
3 Terms, definitions and abbreviations
For the purposes of this document, the following terms, definitions and abbreviations apply.
3.1 Terms and definitions
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
[IEV 731-06-29]
3.1.2
avalanche photodiode
photodiode operating with a bias voltage such that the primary photocurrent undergoes
amplification by cumulative multiplication of charge carriers
[IEV 731-06-30]
3.1.3
pigtail
short optical fibre or optical fibre cable that is attached to a device being measured

– 8 – 62007-2 © IEC:2009
3.2 Abbreviations
LED light emitting diodes
LD laser diode
PD photodiode
TIA transimpedance amplifier
APD avalanche photodiode
4 Measuring methods for photoemitters
4.1 Outline of the measuring methods
The LEDs and LDs have various opto-electronic properties. Some of them are important
specifications for using them in the optical communication systems. The measuring methods
for their opto-electronic properties are described in the following subclauses. Each subclause
consists of following items.
a) Purpose
b) “Equipment setup” or “Circuit diagram” for measurement
c) “Equipment descriptions and requirements” or “Circuit descriptions and requirements”
d) Precautions to be observed
e) Measurement procedures
f) Specified conditions
4.2 Radiant power or forward current of LEDs and LDs with or without optical fibre
pigtails
a) Purpose
To measure the radiant power Φ or the forward current I of light-emitting diodes (LED)
e F
and laser diodes, with or without optical fibre pigtails, under specified conditions.
b) Measuring equipment
Figure 1 shows an equipment setup for measuring radiant power and forward current of
LEDs and LDs.
Integrating sphere
Detector (calibrated)
Device being measured
Diffusing opaque screen
I
F
IEC  2305/08
Figure 1 – Equipment setup for measuring radiant power
and forward current of LEDs and LDs
c) Equipment description and requirements
The radiation emitted by the device is submitted to multiple reflections from the walls
of the integrating sphere; this leads to a uniform irradiance of the surface proportional to

62007-2 © IEC:2009 – 9 –
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 having a high
uniform reflection coefficient (0,8 minimum).
The sphere and detector assembly shall be calibrated.
Change in peak-emission wavelength and flux due to power dissipation shall be taken into
account.
When the device being measured is pulsed, the detector shall average the measured
radiation.
e) Measurement procedures
The emitting device is set at the entrance of the integrating sphere, so that no direct
radiation will reach the detector.
For measurement of radiant power, the specified forward current I is applied to the device
F
and the radiant power is measured on the photodetector.
For measurement of forward current, a current is applied to the device until the specified
radiant power (Φ ) is achieved. The value of current is recorded.
e
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 (f ) of LEDs and LDs with or without optical fibre
c
pigtails
a) Purpose
To measure the small-signal cut-off frequency (f ) of light-emitting diodes (LED) and laser
c
diodes (LD) with or without optical fibre pigtails, under specified conditions.
b) Circuit diagram
Figure 2 shows a circuit diagram for measuring small-signal cut-off frequency
LEDs and LDs.
– 10 – 62007-2 © IEC:2009
C
+
G C
D
G PD M
–
IEC  2306/08
Key
D device being measured
G adjustable frequency a.c. generator
G d.c. generator
PD photodetector
M measuring instrument for a.c. radiant power
C , C coupling capacitors
1 2
Figure 2 – Circuit diagram for measuring small-signal
cut-off frequency LEDs and LDs
c) Precautions to be observed
The radiant power reflected back into the laser-diode shall be minimized so as to avoid
distortions, which could affect the accuracy of the measurements. The photodetector must
have a frequency response greater than f .
c
d) 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 equal to the continuous
forward current above the threshold or specified radiant power.
The forward current is modulated using generator G at a low frequency (less than f /100)
1 c
and the a.c. radiant power is measured on M (see Figure 2).
The modulation frequency is increased, keeping the modulation level constant until the
output radiant power measured on M has halved.
This frequency is the small-signal cut-off frequency (f ).
c
e) Specified conditions
For the light-emitting diodes (LED):
– ambient or case temperature;
– d.c. forward current or radiant power.
For the laser diodes (LD):
– ambient, case or submount temperature;
–  difference between (actual) d.c. forward current and threshold current or radiant power.
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.

62007-2 © IEC:2009 – 11 –
+
D PD
G
–
A
IEC  2307/08
Key
D device being measured
PD photodetector measuring incident radiant power
A ammeter
G generator (pulsed or d.c.)
Figure 3 – Circuit diagram for measuring threshold current of a LD
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 the laser diode (I and Φ ) shall not be overstepped.
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 shows a graph to determine threshold current of lasers.
d Φ
e
Φ
e 2
dI
F
d Φ
e
Φ
e
dI
F
I I
TH F
IEC  2308/08
Figure 4 – Graph to determine threshold current of lasers

– 12 – 62007-2 © IEC:2009
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 light emitting diodes (LED) and laser
diodes (LD), 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.

L
I
I
F R(H)
D PD
AMP F
+
G
+
–
R
L G M
–
IEC  2309/08
Key
G d.c. current generator
D device being measured
L lens system
I forward current
F
PD photodetector
R load resistance
L
I reverse current of the photodetector under optical radiation

R(H)
G d.c. voltage bias generator
AMP a.c. amplifier with gain G
F filter with centre frequency f and equivalent noise bandwidth Δf
0 N
M measuring instrument (for example level meter, etc.)
Figure 5 – Circuit diagram for measuring RIN of LEDs and LDs
c) Precautions to be observed
Radiant power reflected back into the laser diode shall be minimized to avoid distortions
affecting accuracy of the measurements.
d) Measurement procedure
A d.c. current corresponding to the specified radiant power Φ is applied to the device.
e
The noise power N is measured by the measuring instrument M and is replaced by
t
reverse current I of the photodetector, under optical radiation, which is measured
R(H)
simultaneously.
The photo-emitting device being measured is replaced by a radiation source with broad
spectral radiation bandwidth in the same wavelength range.
The irradiant power is adjusted to obtain the same reverse current I of the
R(H)
photodetector under optical radiation as previously measured. The noise power N , which

d
corresponds to the photodetector shot-noise plus amplifier noise, is measured by the
measuring instrument.
RIN is calculated using the formula:

62007-2 © IEC:2009 – 13 –
N − N
t d
RIN =
R × G × Δf × I
L N R(H)
It is expressed in Hz–1.
e) Specified conditions
– Ambient, case or submount temperature.
– Radiant power.
– Centre frequency and equivalent noise bandwidth.
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 input
characteristic of a device at a specified radiant power level and at a specified frequency.
The S parameter is the ratio of the high-frequency reflected voltage V to the high-
11 rl
frequency incident voltage V at the device electrical input port.

il
V
rl
S =
V
il
The equivalent working equation is the following:
Ζ − Z
1 0
S =
Z + Z
1 0
where Z is the input impedance of the device being measured and Z the characteristic
1 0
impedance of the measuring equipment.
b) Circuit diagram
Figure 6 shows the circuit diagram for measuring the S parameter LEDs,
LDs and LD modules.
– 14 – 62007-2 © IEC:2009
G
T DC1 DC2 D PM
CS AL TL
NA
IEC  2310/08
Key
G r.f. generator
T biasing circuit
CS d.c. current source
DC1 directional coupler forward
DC2 directional coupler reverse
AL adjustable transmission line
NA network analyzer
D device being measured
PM radiant power meter
TL test transmission line
Figure 6 – Circuit diagram for measuring the S parameter LEDs,
LDs and LD modules
c) Precautions to be observed
The characteristic impedance of the transmission lines, generator, attenuators, device
measuring socket, T-biasing circuit and loads is matched to a common impedance (usually
50 Ω) over the specified frequency range.
The RF power shall remain low enough to allow for linear operation of the device being
measured D.
Ensure that the optical ports of the device D and the meter PM are aligned.
d) Measurement procedure
– Calibration:
The adjustable line shall balance the test line.
A short circuit is connected to the input line at the location of the device being measured
D.
The a.c. signal frequency is scanned around the specified frequency f, and the adjustable
line length is altered in order to obtain one single point S on the Smith chart (modulus
equals to 1 and phase equals to 180 °).
– Measurement:
The "calibration" short-circuit is replaced by the device being measured D, the bias
conditions are applied as specified (Φ , T , or T , T ), the value of S
e case amb sub 11
corresponding to the reflection coefficient of the device D is read.
e) Specified conditions
– Ambient, case or submount temperature.

62007-2 © IEC:2009 – 15 –
– Supply and drive conditions: Φ or I or ΔI , f, m (modulation depth).
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 diagrams
Figure 7 shows a cathode and an anode connected to the package of a laser diode.

– –
G G
2 1
+ +
D
D
L
V
R PD
D
M
R
L
IEC  2311/08
a) Laser diode: cathode connected to the package

–
G
+
D
D
L
V
R PD
D
M
–
R G
L
+
IEC  2312/08
b) Laser diode: anode connected to the package
Key
D device being measured
PD photodetector calibrated (in watts)
G d.c. current source, monitored through negative feedback by the photocurrent delivered
by the monitor photodiode
G d.c. voltage source
R load resistance
L
V d.c. voltmeter
R
D laser diode
L
D  monitor photodiode
M
Figure 7– Cathode and anode connected to the package of a LD

– 16 – 62007-2 © IEC:2009
c) Precautions to be observed
The optical radiant power reflected back to the laser diode shall be minimized.
The changes in case temperature should be slow enough to insure that thermal equilibrium
takes place inside the module and, in the case of a module with cooler, that the specified
T is stabilized.
sub
d) Measurement procedure
At each measuring point, the current source G is adjusted until the monitor photocurrent
is equal to the value obtained with the specified optical radiation at 25 °C.
The case temperature is scanned over the specified range and the plot of the output
radiant power is recorded against either time (Figure 8) or case temperature (Figure 9).
The tracking error is given by:
Φ − Φ Φ − Φ
o o
emin emax
e25 C e25 C
E = ×100 (%) E = ×100 (%)
R1 R2
Φ Φ
o o
e25 C e25 C
Φ
e
Φ
emax
Φ
emin
t
IEC  2313/08
Figure 8 – Output radiant power versus time

Φ
e
T
T T
min max
IEC  2314/08
Figure 9 – Output radiant power versus case temperature

e) Specified conditions
62007-2 © IEC:2009 – 17 –
– Φ or ΔI at 25 °C.
e F
– Case or ambient temperature range T ; T .
case/amb min case/amb max
– Submount temperature (T ), where appropriate.
sub
– Bias voltage (V ) of the 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 a laser diode (LD) with or without optical fibre
pigtails.
b) Circuit diagram
Figure 10 shows a circuit diagram for measuring linewidth of LDs.

AO/D
L1 L3
OI
M
P1
+
AO
D
G
–
L2
F3
L1
OI
F1
OC
F2
PD SA
AMP
IEC  2315/08
Key
G  d.c. 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 fibre
OC  optical coupler
PD  detector
AMP amplifier
SA  spectrum analyzer
Figure 10 – Circuit diagram for measuring linewidth of LDs
c) 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.

– 18 – 62007-2 © IEC:2009
Modulation frequency should be higher than the spectral linewidth of the device D.
The specified d.c. current should be sufficiently stabilized so as not to broaden the
measured linewidth of the device D.
NOTE The fibre length of F3 should be determined by the frequency resolution:
0,75 c
π L n
where
c is the velocity of light;
L is the length of F3;
n is the refractive index of fibre F3.
d) Measurement procedure
The specifed d.c. current above threshold (ΔI ) or the forward current corresponding to the
F
specified radiant power (Φ ) is applied to the device D being measured.
e
The optical port of the device D is aligned to get maximum radiant power into F1 and F3.
A peak corresponding to the modulation frequency of the modulator AO on the spectrum
analyzer is observed and P1 is rotated to get the maximum radiant power. Full width at
half maximum of the observed peak is measured. The measured value is twice the
spectral linewidth of the device D.
e) Specified conditions
– Ambient, case or submount temperature.
– Forward current above threshold ΔI or radiant power Φ .
F e
4.9 Modulation current at 1 dB efficacy compression (I ) of LEDs
F (1 dB)
a) Purpose
To measure the modulation current at 1 dB efficacy compression under specified
modulation frequency and radiant power output condition.
b) Circuit diagram
Figure 11 shows the circuit diagram for measuring 1-dB efficacy compression of LDs.

62007-2 © IEC:2009 – 19 –
Biasing
circuit
D D
T
C
V
V
FA
+ +
P P
G 1 2
V
V
R R
L1 L2
– –
IEC  2316/08
Key
D  device being measured
G  sine wave signal source
C  coupling capacitor
P  power supply to provide the specified radiant power Φ to D
1 e
V, V , V a.c. voltmeter or broadband voltage measuring equipment
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  filter with bandpass centre frequency matched to the frequency f of the sine wave signal source
A  amplifier
Figure 11 – Circuit diagram for measuring 1 dB efficacy compression of LDs
c) Precautions to be observed
The optical port of the device being measured shall, as far as possible, be coupled to that
of the optical signal detector.

d) Measurement procedure
Couple the optical output of D from the optical port to the detector D . Apply the supply
T
current generated by P to the appropriate connections of D so as to achieve the specified
output radiant power Φ from the optical port. Apply modulation current from signal
e
generator G at the specified modulation frequency. Record the detected signal voltage V
and the modulation voltage V as the modulation current is increased. The modulation
current I (I = V /R ) is determined from V using the value of R . Identify the region for
1 1 1 L1 1 L1
which there is a linear relationship between log V and log I . Record the value of I at
2 1 1
which log V is 1 dB below the value resulting from the projected linear region, as shown
in Figure 17. This value of I is the modulation current at 1 dB efficacy compression
I .
F(1 dB)
NOTE The functions of the filters and a.c. voltmeters are typically incorporated in r.f. spectrum analyzer
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 a.c. signal powers in place of signal
amplitudes.
Figure 12 shows the plot of log V versus log I
.
2 1
– 20 – 62007-2 © IEC:2009
Log V dB
Projected linear region
1 dB
Detected
signal
voltage
Modulation current at
1 dB efficacy compression
Log I dB
IEC  2317/08
Figure 12 – Plot of log V versus log I
2 1
e) 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 (Φ )
e
– Modulation frequency (f)
4.10 Differential efficiency (η ) of a LD with or without pigtail and an LD module
d
a) Purpose
To measure the differential efficiency η of a laser diode (LD) with or without pigtail and
d
an LD module.
b) Circuit diagram and current waveform
Figure 13 shows the circuit diagram for measuring differential efficiency of a LD and
Figure 14 shows the current waveform for differential efficiency measurement.

62007-2 © IEC:2009 – 21 –
I
F
DT
PG V SP
V
F
D
IEC  2318/08
Key
D device being measured  I forward current
F
PG current step generator  V voltmeter
D  photodetector   V device forward voltage as measured on
F
T
SP  signal processing equipment  the voltmeter

Figure 13 – Circuit diagram for measuring differential efficiency of a LD

δI
F
τ
Time
IEC  2319/08
Key
δI step-amplitude
F
τ step duration
Figure 14 – Current waveform for differential efficiency measurement
Current
– 22 – 62007-2 © IEC:2009
c) Precautions to be observed
Radiant power reflected back into the laser diode shall be minimized. The limiting values
of the laser diode, I or Φ , shall not be exceeded.
F e
d) Measurement procedure
The current waveform applied to the device shall be as shown in Figure 16, where δI is
F
the step-amplitude and ≤(1/20)ΔI and τ, the step duration, shall be of sufficient length to
F
allow the device to achieve thermal equilibrium.
NOTE The step duration τ should not be too small, otherwise thermal effects would not be taken into
account. A recommended minimum value is 100 μs, close to the most common chip-to-heatsink thermal time
constant.
Record I and Φ at each step level.
F e
Derive η from the ratio:
d
η = δΦ / δI ,   at ΔI or Φ specified.
d e F F e
e) Specified conditions
– Ambient or case temperature, or sub-mount temperature (T , T or T )
amb case sub
– Either forward current above threshold (ΔI ) or radiant power (Φ )
F e
4.11 Differential (forward) resistance r of an LD with or without pigtail
d
a) Purpose
To measure the differential (forward) resistance r of a laser diode (LD) with/without
d
pigtail.
b) Circuit diagram and current waveform
Figure 15 shows the circuit diagram for measuring differential resistance and Figure 16
shows the current waveform for differential resistance.

I
F
DT
PG V SP
F V
D
IEC  2320/08
Key
D  device being measured  SP  signal processing equipment
PG current step generator  I forward current
F
V  voltmeter   V device forward voltage as measured on
F
D  photodetector   the voltmeter
T
Figure 15 – Circuit diagram for measuring differential resistance

62007-2 © IEC:2009 – 23 –
δI
F
τ
Time
IEC  2319/08
Key
δI step-amplitude
F
τ step duration
Figure 16 – Current waveform for differential resistance
c) Precautions to be
...