IEC TR 62324:2007
(Main)Single-mode optical fibres - Raman gain efficiency measurement using continuous wave method - Guidance
Single-mode optical fibres - Raman gain efficiency measurement using continuous wave method - Guidance
This technical report is applicable to the Raman gain efficiency measurement of a single-mode transmission optical fibre. It is useful in assessing the fibre's performance in Raman amplified transmission systems. This technical report describes a method that uses two unmodulated continuous waves to measure the Raman gain efficiency of a single-mode transmission optical fibre. This parameter assesses the fibre's efficiency at converting input pump power to information signal power. This second edition differs from the first in that in the previous edition, in the paragraph before Figure 2, there was an approximation of the relationship between wavelength and optical frequency that led to some inconsistencies in interlaboratory agreement. This approximation has been removed.
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TECHNICAL IEC
REPORT TR 62324
Second edition
2007-01
Single-mode optical fibres –
Raman gain efficiency measurement
using continuous wave method –
Guidance
Reference number
IEC/TR 62324:2007(E)
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TECHNICAL IEC
REPORT TR 62324
Second edition
2007-01
Single-mode optical fibres –
Raman gain efficiency measurement
using continuous wave method –
Guidance
© IEC 2007 ⎯ Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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Commission Electrotechnique Internationale M
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
– 2 – TR 62324 © IEC:2007(E)
CONTENTS
FOREWORD.3
1 Scope and object.5
2 Normative references .5
3 Terms and definitions .5
4 Overview .6
5 Method .7
5.1 Description.7
5.2 Laser safety .8
6 Apparatus.8
6.1 Optical pump source .8
6.2 Optical signal source.9
6.3 Optical signal conditioning.10
6.4 Power meter.10
6.5 Optical spectrum analyzer .10
6.6 Examples .10
7 Sampling and specimens.10
7.1 Specimen endfaces .10
7.2 Specimen length.10
7.3 Length selection .10
7.4 Specimen attenuation coefficient .10
8 Procedure .11
9 Calculations and interpretation of results.11
9.1 On/off gain .11
9.2 Raman gain efficiency .11
10 Documentation .11
10.1 Information to be reported with each measurement .11
10.2 Information that should be available upon request.11
Bibliography.12
Figure 1 – Typical test set-up for measuring the Raman gain efficiency of a fibre .7
Figure 2 – Raman gain efficiency of depolarized light for a dispersion-unshifted fibre
pumped at 1 486 nm [4] .8
Table 1 – Examples of parameters for measuring Raman efficiency.10
TR 62324 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SINGLE-MODE OPTICAL FIBRES –
RAMAN GAIN EFFICIENCY MEASUREMENT
USING CONTINUOUS WAVE METHOD –
GUIDANCE
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
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The main task of IEC technical committees is to prepare International Standards. However, a
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data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC/TR 62324, which is a technical report, has been prepared by subcommittee 86A: Fibres
and cables, of IEC technical committee 86: Fibre optics.
This second edition cancels and replaces the first edition published in 2003. It constitutes a
technical revision.
This second edition differs from the first in that in the previous edition, in the paragraph
before Figure 2, there was an approximation of the relationship between wavelength and
optical frequency that led to some inconsistencies in interlaboratory agreement. This
approximation has been removed.
– 4 – TR 62324 © IEC:2007(E)
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
86A/1058/DTR 86A/1072/RVC
Full information on the voting for the approval of this technical report 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.
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.
A bilingual version of this publication may be issued at a later date.
TR 62324 © IEC:2007(E) – 5 –
SINGLE-MODE OPTICAL FIBRES –
RAMAN GAIN EFFICIENCY MEASUREMENT
USING CONTINUOUS WAVE METHOD –
GUIDANCE
1 Scope and object
This technical report is applicable to the Raman gain efficiency measurement of a single-
mode transmission optical fibre. It is useful in assessing the fibre's performance in Raman
amplified transmission systems.
This technical report describes a method that uses two unmodulated continuous waves to
measure the Raman gain efficiency of a single-mode transmission optical fibre. This
parameter assesses the fibre's efficiency at converting input pump power to information signal
power.
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 60793-1-22, Optical fibres – Part 1-22: Measurement methods and test procedures –
Length measurement
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation
IEC 60825-1, Safety of laser products – Part 1: Equipment classification, requirements and
user's guide
IEC 60825-2, Safety of laser products – Part 2: Safety of optical fibre communication systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
effective length
L
eff
the fibre’s effective length accounts for decreasing nonlinear effects as light attenuates along
a fibre’s length, and is defined as:
−0,23αL
1−e
L = (1)
eff
0,23α
where α is the fibre attenuation coefficient in decibels per kilometre (dB/km), and L is the fibre
length in kilometres (km).
NOTE 1 When the α in equation (1) is expressed in nepers per kilometre (Np/km), the two occurrences of 0,23
disappear, and the resultant equation is the form that typically appears in the technical literature.
– 6 – TR 62324 © IEC:2007(E)
NOTE 2 When 0,23αL >>1, equation (1) simplifies to give L ≈ 1/(0,23α), which is the length at which the power
eff
in the fibre has decreased by a factor of 1/e. As an example, L = 17,4 km when α = 0,25 dB/km.
eff
3.2
depolarized light
light whose electric field vector, described in a plane perpendicular to the direction of
propagation, is uniformly distributed in all radial directions
NOTE 1 Rotation of a polarizer in a beam of depolarized light reduces its intensity by 50% regardless of the
polarizer's angular orientation. This test, however, is not sufficient to assess whether the light is depolarized
because circularly polarized ligh
...
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