IEC TR 61292-6:2023

Optical amplifiers - Part 6: Distributed Raman amplification

IEC TR 61292-6:2023 is available as IEC TR 61292-6:2023 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC TR 61292-6:2023 which is a Technical Report, relates to distributed Raman amplification (DRA). Its main purpose is to provide background material for future standards related to DRA, such as specifications, test methods and operating procedures. This document covers the following aspects:
- general overview of Raman amplification;
- applications of DRA;
- performance characteristics and test methods related to DRA;
- operational issues relating to the deployment of DRA.
As DRA is a relatively new technology, and still rapidly evolving, some of the material in this document can become obsolete or irrelevant in a fairly short period of time. This document will be updated frequently to minimize this possibility. This second edition cancels and replaces the first edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- correction of the formula for noise figure;
- correction of errors in Figure 10.

General Information

• Status: Published
• Publication Date: 10-Jan-2023
• ICS: 33.160.10 - Amplifiers
• ICS: 33.180.30 - Optic amplifiers
• Technical Committee: SC 86C - Fibre optic systems and active devices
• Drafting Committee: WG 3 - TC 86/SC 86C/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 02-Feb-2023
• Completion Date: 11-Jan-2023

Relations

• Revises: IEC TR 61292-6:2010 - Optical amplifiers - Part 6: Distributed Raman amplification
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 61292-6 ®
Edition 2.0 2023-01
TECHNICAL
REPORT
colour
inside
Optical amplifiers –
Part 6: Distributed Raman amplification
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

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The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TR 61292-6 ®
Edition 2.0 2023-01
TECHNICAL
REPORT
colour
inside
Optical amplifiers –
Part 6: Distributed Raman amplification

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.10; 33.180.30 ISBN 978-2-8322-6340-2

– 2 – IEC TR 61292-6:2023  IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 7
4 Background . 8
4.1 General . 8
4.2 Raman amplification process . 8
4.3 Distributed vs. lumped amplification . 10
4.4 Tailoring the Raman gain spectrum . 11
4.5 Forward and backward pumping configuration . 11
4.6 Typical performance of DRA . 13
5 Applications of distributed Raman amplification . 14
5.1 General . 14
5.2 All-Raman systems . 14
5.3 Hybrid EDFA Raman systems . 15
5.3.1 General . 15
5.3.2 Long repeaterless links . 15
5.3.3 Long span masking in multi-span links . 16
5.3.4 High capacity long haul and ultra-long-haul systems . 16
6 Performance characteristics and test methods . 16
6.1 General . 16
6.2 Performance of the Raman pump module. 16
6.2.1 Basic configuration . 16
6.2.2 Pump wavelengths. 17
6.2.3 Pump output power . 17
6.2.4 Pump degree-of-polarization (DOP) . 17
6.2.5 Pump relative intensity noise (RIN) . 18
6.2.6 Insertion loss . 18
6.2.7 Other passive characteristics . 19
6.3 System level performance . 19
6.3.1 General . 19
6.3.2 On-off signal gain . 19
6.3.3 Gain flatness . 20
6.3.4 Polarization dependant gain (PDG) . 21
6.3.5 Equivalent noise figure . 21
6.3.6 Multi-path interference (MPI) . 21
7 Operational issues . 22
7.1 General . 22
7.2 Dependence of Raman gain on transmission fibre . 22
7.3 Fibre line quality . 23
7.4 High pump power issues . 23
7.4.1 General . 23
7.4.2 Laser safety . 24

7.4.3 Damage to the fibre line. 24
8 Conclusions . 25
Bibliography . 26

Figure 1 – Stimulated Raman scattering process and Raman gain spectrum for silica
fibres . 9
Figure 2 – Distributed vs. lumped amplification . 10
Figure 3 – The use of multiple pump wavelengths to achieve flat broadband gain . 11
Figure 4 – Simulation results showing pump and signal propagation along an SMF
span . 12
Figure 5 – On-off gain and equivalent NF for SMF using a dual pump backward DRA
with pumps at 1 424 nm and 1 452 nm . 13
Figure 6 – Typical configuration of an amplification site in an all-Raman system . 15
Figure 7 – Typical configuration of a Raman pump module used for counter-
propagating DRA . 17
Figure 8 – Model for signal insertion loss (IL) of a Raman pump module used for
counter-propagating DRA. 18
Figure 9 – Typical configuration used to measure on-off gain of DRA . 20
Figure 10 – Variations of Raman on-off gain for different transmission fibres . 23

– 4 – IEC TR 61292-6:2023  IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL AMPLIFIERS –
Part 6: Distributed Raman amplification

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.
IEC TR 61292-6 has been prepared by subcommittee 86C: Fibre optic systems and active
devices, of IEC technical committee 86: Fibre optics. It is a Technical Report.
This second edition cancels and replaces the first edition published in 2010. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) correction of the formula for noise figure;
b) correction of errors in Figure 10.

The text of this Technical Report is based on th
...

IEC TR 61292-6 ®
Edition 2.0 2023-01
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Optical amplifiers –
Part 6: Distributed Raman amplification

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TR 61292-6 ®
Edition 2.0 2023-01
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Optical amplifiers –
Part 6: Distributed Raman amplification
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.10; 33.180.30 ISBN 978-2-8322-6366-2

– 2 – IEC TR 61292-6:2023 RLV  IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 8
4 Background . 8
4.1 General . 8
4.2 Raman amplification process . 9
4.3 Distributed vs. lumped amplification . 10
4.4 Tailoring the Raman gain spectrum . 11
4.5 Forward and backward pumping configuration . 11
4.6 Typical performance of DRA . 13
5 Applications of distributed Raman amplification . 14
5.1 General . 14
5.2 All-Raman systems . 14
5.3 Hybrid EDFA Raman systems . 15
5.3.1 General . 15
5.3.2 Long repeaterless links . 15
5.3.3 Long span masking in multi-span links . 16
5.3.4 High capacity long haul and ultra-long-haul systems . 16
6 Performance characteristics and test methods . 16
6.1 General . 16
6.2 Performance of the Raman pump module. 16
6.2.1 Basic configuration . 16
6.2.2 Pump wavelengths. 17
6.2.3 Pump output power . 17
6.2.4 Pump degree-of-polarization (DOP) . 17
6.2.5 Pump relative intensity noise (RIN) . 18
6.2.6 Insertion loss . 18
6.2.7 Other passive characteristics . 19
6.3 System level performance . 19
6.3.1 General . 19
6.3.2 On-off signal gain . 19
6.3.3 Gain flatness . 21
6.3.4 Polarization dependant gain (PDG) . 21
6.3.5 Equivalent noise figure . 21
6.3.6 Multi-path interference (MPI) . 22
7 Operational issues . 22
7.1 General . 22
7.2 Dependence of Raman gain on transmission fibre . 22
7.3 Fibre line quality . 23
7.4 High pump power issues . 24
7.4.1 General . 24
7.4.2 Laser safety . 24

7.4.3 Damage to the fibre line. 24
8 Conclusions . 25
Bibliography . 26

Figure 1 – Stimulated Raman scattering process and Raman gain spectrum for silica
fibres . 9
Figure 2 – Distributed vs. lumped amplification . 11
Figure 3 – The use of multiple pump wavelengths to achieve flat broadband gain . 11
Figure 4 – Simulation results showing pump and signal propagation along an SMF
span . 12
Figure 5 – On-off gain and equivalent NF for SMF using a dual pump backward DRA
with pumps at 1 424 nm and 1 452 nm . 13
Figure 6 – Typical configuration of an amplification site in an all-Raman system . 15
Figure 7 – Typical configuration of a Raman pump module used for counter-
propagating DRA . 17
Figure 8 – Model for signal insertion loss (IL) of a Raman pump module used for
counter-propagating DRA. 19
Figure 9 – Typical configuration used to measure on of gain (a)
for co-propagating DRA and (b) for counter-propagating DRA on-off gain of DRA . 20
Figure 10 – Variations of Raman on-off gain for different transmission fibres . 23

– 4 – IEC TR 61292-6:2023 RLV  IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL AMPLIFIERS –
Part 6: Distributed Raman amplification

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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC TR 61292-6:2010. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
strikethrough red text.
IEC TR 61292-6 has been prepared by subcommittee 86C: Fibre optic systems and active
devices, of IEC technical committee 86: Fibre optics. It is a Technical Report.
This second edition cancels and replaces the first edition published in 2010. This edition
constitutes a technica
...