Optical amplifiers - Test methods - Part 4-3: Power transient parameters - Single channel optical amplifiers in output power control

IEC 61290-4-3:2015(E) applies to output power controlled optically amplified, elementary sub-systems. It applies to optical fibre amplifiers (OFA) using active fibres containing rare-earth dopants, presently commercially available, as indicated in IEC 61291-1, as well as alternative optical amplifiers that can be used for single channel output power controlled operation, such as semiconductor optical amplifiers (SOA). The object of this standard is to provide the general background for optical amplifier (OA) power transients and its measurements and to indicate those IEC standard test methods for accurate and reliable measurements of the following transient parameters: - Transient power response; - Transient power overcompensation response; - Steady-state power offset; - Transient power response time. The stimulus and responses behaviours under consideration include: - Channel power increase (step transient); - Channel power reduction (inverse step transient); - Channel power increase/reduction (pulse transient); - Channel power reduction/increase (inverse pulse transient); - Channel power increase/reduction/increase (lightning bolt transient); - Channel power reduction/increase/reduction (inverse lightning bolt transient). These parameters have been included to provide a complete description of the transient behaviour of an output power transient controlled OA. The test definition defined here are applicable if the amplifier is an OFA or an alternative OA. However, the description in Annex A of this document concentrates on the physical performance of an OFA and provides a detailed description of the behaviour of OFA; it does not give a similar description of other OA types. Keywords: output power controlled optically amplified elementary sub-systems, optical fibre amplifiers, rare-earth dopants

Optische Verstärker - Prüfverfahren - Teil 4-3: Leistungs-Transientenkenngrößen von Ein-Kanal-LWL-Verstärkern mit Ausgangs-Leistungskontrolle

Amplificateurs optiques - Méthodes d'essai - Partie 4-3: Paramètres de puissance transitoire - Contrôle de la puissance de sortie des amplificateurs optiques monocanaux

Optični ojačevalniki - Preskusne metode - 4-3. del: Električni parametri ojačanja - Enokanalni optični ojačevalniki za izhodno krmiljenje moči (IEC 61290-4-3:2015)

Ta del standarda IEC 61290 velja za optično ojačane osnovne podsisteme z izhodnim krmiljenjem moči. Velja za ojačevalnike z optičnimi vlakni (OFA), ki uporabljajo aktivna vlakna s trenutno komercialno dostopnimi redkimi zemeljskimi dopanti, kot je navedeno v standardu IEC 61291-1, ter tudi za alternativne optične ojačevalnike, ki jih je mogoče uporabiti za enokanalno izhodno krmiljenje moči, kot so polprevodniški optični ojačevalniki (SOA).
Cilj tega standarda je zagotoviti splošno ozadje za ojačanje moči optičnih ojačevalnikov (OA) in njihove meritve ter določitev tistih standardnih preskusnih metod IEC, ki zagotavljajo natančne in zanesljive meritve naslednjih parametrov ojačanja:
a) odziv ojačane moči;
b) odziv prekomerne kompenzacije ojačane moči;
c) izravnava moči pri ustaljenih razmerah;
d) odzivni čas ojačane moči.
Obravnavana vedenja stimulusov in odzivov vključujejo naslednje:
1) povečanje moči kanala (koračno ojačanje);
2) zmanjšanje moči kanala (obratno koračno ojačanje);
3) povečanje/zmanjšanje moči kanala (pulzno ojačanje);
4) zmanjšanje/povečanje moči kanala (obratno pulzno ojačanje);
5) povečanje/zmanjšanje/povečanje moči kanala (bliskovito ojačanje);
6) zmanjšanje/povečanje/zmanjšanje moči kanala (obratno bliskovito ojačanje).
Ti parametri so bili vključeni z namenom zagotovitve popolnega opisa ojačevalnega vedenja optičnega ojačevalnika (OA) za izhodno krmiljenje moči. Tukaj opredeljena definicija preskusa velja, če je ojačevalnik tipa OFA ali OA. Vendar se opis v dodatku A tega dokumenta osredotoča na fizično zmogljivost ojačevalnika z optičnimi vlakni (OFA) in zagotavlja podroben opis vedenja takšnega ojačevalnika; ne podaja podobnega opisa drugih vrst optičnih ojačevalnikov (OA).

General Information

Status
Withdrawn
Publication Date
19-Nov-2015
Current Stage
6060 - Document made available
Due Date
04-Feb-2016

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SLOVENSKI STANDARD
SIST EN 61290-4-3:2016
01-februar-2016

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Optical amplifiers - Test methods - Part 4-3: Power transient parameters - Single channel

optical amplifiers in output power control (IEC 61290-4-3:2015)

Optische Verstärker - Prüfverfahren - Teil 4-3: Leistungs-Transientenkenngrößen von Ein

-Kanal-LWL-Verstärkern mit Ausgangs-Leistungskontrolle (IEC 61290-4-3:2015)
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Ta slovenski standard je istoveten z: EN 61290-4-3:2015
ICS:
33.180.30 2SWLþQLRMDþHYDOQLNL Optic amplifiers
SIST EN 61290-4-3:2016 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 61290-4-3:2016
---------------------- Page: 2 ----------------------
SIST EN 61290-4-3:2016
EUROPEAN STANDARD EN 61290-4-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2015
ICS 33.180.30
English Version
Optical amplifiers - Test methods - Part 4-3: Power transient
parameters - Single channel optical amplifiers in output power
control
(IEC 61290-4-3:2015)

Amplificateurs optiques - Méthodes d'essai - Partie 4-3: Optische Verstärker - Prüfverfahren - Teil 4-3: Leistungs-

Paramètres de puissance transitoire - Contrôle de la Transientenkenngrößen von Ein-Kanal-LWL-Verstärkern

puissance de sortie des amplificateurs optiques mit Ausgangs-Leistungskontrolle
monocanaux (IEC 61290-4-3:2015)
(IEC 61290-4-3:2015)

This European Standard was approved by CENELEC on 2015-06-09. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 61290-4-3:2015 E
---------------------- Page: 3 ----------------------
SIST EN 61290-4-3:2016
EN 61290-4-3:2015
European foreword

The text of document 86C/1310/FDIS, future edition 1 of IEC 61290-4-3, 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 approved by CENELEC as EN 61290-4-3:2015.
The following dates are fixed:
(dop) 2016-05-20
• latest date by which the document has to be implemented at
national level by publication of an identical national
standard or by endorsement
(dow) 2018-06-09
• latest date by which the national standards conflicting with
the document have to be withdrawn
This standard is to be used in conjunction with EN 61290-1:2012.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
Endorsement notice

The text of the International Standard IEC 61290-4-3:2015 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 61290-3-3 NOTE Harmonized as EN 61290-3-3.
IEC 61290-4-1 NOTE Harmonized as EN 61290-4-1.
---------------------- Page: 4 ----------------------
SIST EN 61290-4-3:2016
EN 61290-4-3:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod),

the relevant EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is

available here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 61291-1 2012 Optical amplifiers - EN 61291-1 2012
Part 1: Generic specification
---------------------- Page: 5 ----------------------
SIST EN 61290-4-3:2016
---------------------- Page: 6 ----------------------
SIST EN 61290-4-3:2016
IEC 61290-4-3
Edition 1.0 2015-05
INTERNATIONAL
STANDARD
colour
inside
Optical amplifiers – Test methods
Part 4-3: Power transient parameters – Single channel optical amplifiers in
output power control
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.180.30 ISBN 978-2-8322-2670-4

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 7 ----------------------
SIST EN 61290-4-3:2016
– 2 – IEC 61290-4-3:2015 © IEC 2015
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope .............................................................................................................................. 5

2 Normative references ...................................................................................................... 5

3 Terms, definitions and abbreviations ............................................................................... 6

3.1 Terms and definitions .............................................................................................. 6

3.2 Abbreviations .......................................................................................................... 7

4 Apparatus ........................................................................................................................ 7

4.1 Test set-up ............................................................................................................. 7

4.2 Characteristics of test equipment ............................................................................ 8

5 Test sample ..................................................................................................................... 9

6 Procedure ........................................................................................................................ 9

6.1 Test preparation...................................................................................................... 9

6.2 Test conditions ....................................................................................................... 9

7 Calculations ................................................................................................................... 10

8 Test results ................................................................................................................... 11

8.1 Test settings ......................................................................................................... 11

8.2 Test data .............................................................................................................. 12

Annex A (informative) Overview of power transient events in single channel EDFA .............. 13

A.1 Background........................................................................................................... 13

A.2 Characteristic input power behaviour .................................................................... 13

A.3 Parameters for characterizing transient behaviour ................................................ 15

Annex B (informative) Background on power transient phenomena in a single channel

EDFA .................................................................................................................................... 17

B.1 Amplifier chains in optical networks ...................................................................... 17

B.2 Typical optical amplifier design ............................................................................. 17

B.3 Approaches to address detection errors ................................................................ 19

Annex C (informative) Slew rate effect on transient gain response ....................................... 23

Bibliography .......................................................................................................................... 24

Figure 1 – Power transient test set-up..................................................................................... 8

Figure 2 – OA output power transient response of a) input power increase ........................... 11

Figure A.1 – Example OA input power transient cases for a receiver application ................... 14

Figure A.2 – Input power measurement parameters for a) input power increase and b)

input power decrease ............................................................................................................ 15

Figure A.3 – OA output power transient response of a) input power increase and b)

input power decrease ............................................................................................................ 16

Figure B.1 – Transient response to a) input power drop (inverse step transient) with

transient control, b) deactivated (constant pump power), and c) activated

(power control)...................................................................................................................... 21

Figure B.2 – Transient response to a) input power rise (step transient) with transient

control, b) deactivated (constant pump power), and c) activated (power control) ................... 22

Table 1 – Examples of transient control measurement test conditions ................................... 10

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SIST EN 61290-4-3:2016
IEC 61290-4-3:2015 © IEC 2015 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL AMPLIFIERS – TEST METHODS
Part 4-3: Power transient parameters –
Single channel optical amplifiers in output power control
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) 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 61290-4-3 has been prepared by subcommittee 86C: Fibre optic

systems and active devices, of IEC technical committee 86: Fibre optics.

This International Standard is to be used in conjunction with IEC 61291-1:2012, on the basis

of which it was established.
The text of this standard is based on the following documents:
FDIS Report on voting
86C/1310/FDIS 86C/1329/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.

---------------------- Page: 9 ----------------------
SIST EN 61290-4-3:2016
– 4 – IEC 61290-4-3:2015 © IEC 2015

A list of all parts of the IEC 61290 series, published under the general title Optical amplifiers –

Test methods can be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website 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.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
___________

The first editions of some of these parts were published under the general title Optical fibre amplifiers – Basic

specification or Optical amplifier test methods.
---------------------- Page: 10 ----------------------
SIST EN 61290-4-3:2016
IEC 61290-4-3:2015 © IEC 2015 – 5 –
OPTICAL AMPLIFIERS – TEST METHODS
Part 4-3: Power transient parameters –
Single channel optical amplifiers in output power control
1 Scope

This part of IEC 61290 applies to output power controlled optically amplified, elementary sub-

systems. It applies to optical fibre amplifiers (OFA) using active fibres containing rare-earth

dopants, presently commercially available, as indicated in IEC 61291-1, as well as alternative

optical amplifiers that can be used for single channel output power controlled operation, such

as semiconductor optical amplifiers (SOA).

The object of this standard is to provide the general background for optical amplifier (OA)

power transients and its measurements and to indicate those IEC standard test methods for

accurate and reliable measurements of the following transient parameters:
a) Transient power response
b) Transient power overcompensation response
c) Steady-state power offset
d) Transient power response time
The stimulus and responses behaviours under consideration include:
1) Channel power increase (step transient)
2) Channel power reduction (inverse step transient)
3) Channel power increase/reduction (pulse transient)
4) Channel power reduction/increase (inverse pulse transient)
5) Channel power increase/reduction/increase (lightning bolt transient)
6) Channel power reduction/increase/reduction (inverse lightning bolt transient)

These parameters have been included to provide a complete description of the transient

behaviour of an output power transient controlled OA. The test definition defined here are

applicable if the amplifier is an OFA or an alternative OA. However, the description in

Annex A of this document concentrates on the physical performance of an OFA and provides

a detailed description of the behaviour of OFA; it does not give a similar description of other

OA types.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61291-1:2012, Optical amplifiers – Part 1: Generic specification
---------------------- Page: 11 ----------------------
SIST EN 61290-4-3:2016
– 6 – IEC 61290-4-3:2015 © IEC 2015
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
input signal
optical signal that is input to the OA
3.1.2
input power excursion

relative input power difference in dB before, during and after the input power stimulus event

that causes an OA transient power excursion.
3.1.3
input power rise time

time it takes for the input optical signal to rise from 10 % to 90 % of the total difference

between the initial and final signal levels during an increasing power excursion event

Note 1 to entry: see Figure A.2
3.1.4
input power fall time

time it takes for the input optical signal to fall from 10 % to 90 % of the total difference

between the initial and final signal levels during a decreasing power excursion event

Note 1 to entry: see Figure A.2
3.1.5
slew rate

maximum rate of change of the input optical signal during a power excursion event

3.1.6
transient power response

maximum or minimum deviation (overshoot or undershoot) in dB between the OA’s target

power and the observed power excursion induced by a change in an input channel power

excursion

Note 1 to entry: Once the output power of an amplified channel deviates from its target power, the control

electronics in the OA should attempt to compensate for the power difference or transient power response, bringing

the OA output power back to its original target level.
3.1.7
transient power settling time

amount of time taken to restore the power of the OA to a stable power level close to the target

power level

Note 1 to entry: This parameter is measured from the time when stimulus event that created the power fluctuation

to the time at which the OA power response is stable and within specification.
3.1.8
transient power overcompensation response

maximum deviation in dB between the amplifier’s target output power and the power resulting

from the control electronics instability

Note 1 to entry: Transient power overcompensation response occurs after a power excursion, when an amplifier’s

control electronics attempts to bring the power back to the amplifier’s target level. The control process is iterative,

and control electronics may initially overcompensate for the power excursion until subsequently reaching the

desired target power level.
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SIST EN 61290-4-3:2016
IEC 61290-4-3:2015 © IEC 2015 – 7 –

Note 2 to entry: The transient power overcompensation response parameter is generally of lesser magnitude than

the transient power response and has the opposite sign.
3.1.9
steady state power offset

difference in dB between the final and initial output power of the OA, prior to the power

excursion stimulus event

Note 1 to entry: Normally, the steady state power level following a power excursion differs from the OA power

before the input power stimulus event. The transient controller attempts to overcome this offset using feedback.

3.2 Abbreviations
AFF ASE flattening filter
AGC automatic gain controller
APC automatic power control
ASE amplified spontaneous emission
ASEP amplified spontaneous emission power
BER bit error ratio
DFB distributed feedback (laser)
DWDM dense wavelength division multiplexing
EDF Erbium-doped fibre
EDFA Erbium-doped fibre amplifier
GFF gain flattening filter
NEM network equipment manufacturers
NSP network service providers
O/E optical-to-electrical
OA optical amplifier
OD optical damage
OFA optical fibre amplifier
OSA optical spectrum analyser
OSNR optical signal-to-noise ratio
PDs photodiodes
PID proportional integral derivative
SOA semiconductor optical amplifier
SAR signal-to-ASE ratio
SigP signal power
SOP state of polarization
VOA variable optical attenuator
WDM wavelength division multiplexing
4 Apparatus
4.1 Test set-up

Figure 1 shows a generic set-up to characterise the transient response properties of output

power controlled single channel OAs.
---------------------- Page: 13 ----------------------
SIST EN 61290-4-3:2016
– 8 – IEC 61290-4-3:2015 © IEC 2015
Channel pass-
Optical
Polarization
under
Laser source
VOA
band filter
modulator
scrambler
test
O/E converter
Function generator
Oscilloscope
IEC
Figure 1 – Power transient test set-up
4.2 Characteristics of test equipment
The test equipment listed below is needed, with the required characteristics

a) Laser source for supplying the OA input signal with the following characteristics:

– Ability to support the range of signal wavelengths for which the OA under test is to be

tested. This could be provided for example by a tuneable laser, or a bank of distributed

feedback (DFB) lasers.

– An achievable average output power such that at the input to the OA under test the

power will be above the maximum specified input power of the OA, including loss of

any subsequent test equipment between the laser source and OA under test.

b) Polarization scrambler to randomize the incoming polarization state of the laser source, or

to control it to a defined state of polarization (SOP). The polarization scrambler is

optional.

c) Variable optical attenuator (VOA) with a dynamic range sufficient to support the required

range of surviving signal levels at which the OA under test is to be tested.

NOTE If the output power of the laser source can be varied over the required dynamic range, then a VOA is

not needed.

d) Optical modulator to modify the OA input signal to the defined power excursion with the

following characteristics.

– Extinction ratio at rewrite without putting number higher than the maximum drop level

for which the OA under test is to be tested.

– Switching time fast enough to support the fastest slew rate for which the OA under test

is to be tested.

e) Channel pass-band filter: an optical filter designed to distinguish the signal wavelength

with the following characteristics. Note the use of a channel pass-band filter is optional.

– Ability to support the range of signal wavelengths for which the OA under test is to be

tested. This could be provided for example by a tuneable filter, or a series of discrete

filters.
– 1dB pass-band of at least ±20 GHz centred around the signal wavelength.

– At least 20 dB attenuation level below the minimum insertion loss across the entire

specified transmission band of the OA under test except within a range of ±100 GHz

centred around the signal wavelength.

f) Opto-electronic (O/E) convertor to detect the filtered output of the OA under test with the

following characteristics.

– A sufficiently wide optical and electrical bandwidth to support the fastest slew rate for

which the OA is to be tested.

– A linear response within a ±5 dB range of all signal levels for which the OA under test

is to be tested.
---------------------- Page: 14 ----------------------
SIST EN 61290-4-3:2016
IEC 61290-4-3:2015 © IEC 2015 – 9 –

g) Oscilloscope to measure and capture the transient response of the optically filtered output

of the OA under test, with a sufficiently wide electrical bandwidth to support the fastest

slew rate for which the OA is to be tested.

h) Function generator to generate the input power transient waveforms to drive the optical

modulator, with electrical pulse width short enough and electrical slew rate high enough to

support the fastest slew rate for which the OA under test is to be tested.
5 Test sample

The OA shall operate under nominal operating conditions. If the OA is likely to cause laser

oscillations due to unwanted reflections, optical isolators should be used to isolate the OA

under test. This will minimize signal instability.
6 Procedure
6.1 Test preparation

In the set-up shown in Figure 1, the input optical signal power injected into the amplifier being

tested is generated from a suitable laser source. The optical power is passed through an

optional polarization scrambler to allow randomization or control of the signal polarization

state and is subsequently adjusted with a VOA to the desired optical input power levels. The

signal then passes through an optical modulator driven by a function generator that provides

the desired input power test waveform to stimulate the transient input power excursions. The

signal is then injected into the amplifier being tested. A channel pass-band filter (such as a

tuneable optical filter, fixed optical filter or similar component) may be used to select only the

relevant channel wavelength under test, followed by an O/E converter and an oscilloscope at

the output of the amplifier. The output channel selected by the optional channel pass-band

filter and its transient response is monitored with the O/E converter and oscilloscope.

Waveforms similar to those shown in Figure A.3 are captured via the oscilloscope for

subsequent computer processing.

Prior to measurement of the transient response, the input power waveform trace shall be

recorded. Use the set-up of Figure 1 without the OFA under test. The input optical connector

from the optical modulator is connected to the channel pass filter.

For this test to stimulate a power excursion at the input of the OA under test, the source laser

power at the OA input is set at some typical power level. The function generator waveform is

chosen to increase or decrease the input power to the OA under test with power excursions

and slew rate relevant to the defined test condition. For example, for a typical number in the

case of an optical receiver, the input power to the OA could be increased by 7 dB in a

timeframe of 50 µs and then held at this power value to simulate a power increase transient

power response (step transient) condition as shown in Figure A.1(1). For alternative transient

control measurements, the signal generator waveform is controlled appropriately, and the

VOA is adjusted accordingly.
6.2 Test conditions

Several sequential transient control measurements can be performed according to the optical

amplifier’s specified operating conditions. Examples of power excursion scenarios are shown

in Table 1. These measurements are typically performed over a broad range of input power

levels.
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SIST EN 61290-4-3:2016
– 10 – IEC 61290-4-3:2015 © IEC 2015
Table 1 – Examples of transient control measurement test conditions
Scenario Power excursion Slew rate
Input power step transient increase/reduction 3 dB, 7 dB 500 µs, 200 µs, 50 µs
Input power pulse transient 3 dB, 7 dB
500 µs, 200 µs, 50 µs
Input power lightning bolt transient ±3 dB, ±7 dB 500 µs, 200 µs, 50 µs
7 Calculations

Transient parameters can be calculated by processing amplifier output power transient

wave
...

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