IEC TR 62469:2007

IEC/TR 62469
Edition 1.0 2007-08
TECHNICAL
REPORT
Guidance for residual stress measurement of optical fibre

IEC/TR 62469:2007(E)
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IEC/TR 62469
Edition 1.0 2007-08
TECHNICAL
REPORT
Guidance for residual stress measurement of optical fibre

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
P
ICS 33.180.10 ISBN 2-8318-9301-1

– 2 – TR 62469 © IEC:2007(E)
CONTENTS
FOREWORD.3

1 Scope.5
2 Justification of measurement .5
3 Apparatus.6
3.1 General .6
3.2 Light source .6
3.3 Polarizer and analyzer.6
3.4 Sample fibre preparation .6
3.5 Variable phase compensator .6
3.6 Optical intensity detection .7
3.7 Data acquisition .7
4 Data analysis and formula .7
4.1 General .7
4.2 1-D stress profile for a fibre with a cylindrically symmetric structure .8
4.3 2-D stress profile for a fibre with a cylindrically non-symmetric structure .9
5 Measurement procedure.12
5.1 Alignment of polarizer and analyzer.12
5.2 Fibre mounting .12
5.3 Taking transmitted intensity data .12
I ( y,θ )
5.4 Calculation of 1-D stress profile for a fibre with a cylindrically symmetric
structure.12
5.5 Calculation of 2-D stress profile for a fibre with a cylindrically non-symmetric
structure.12
6 Documentation .12
6.1 Information to be reported for each measurement .12
6.2 Information that should be available upon request.13

Bibliography.14

Figure 1 – Polariscopic phase retardation measurement setup for an optical fibre .6
Figure 2 – Measured transmission intensity as a function of fibre radius and external
phase .7
Figure 3 – Propagation of laser light across the fibre cross-section.8
Figure 4 – Stress profile for a fibre with depressed inner cladding and jacketed tube .9
Figure 5 – Examples of projected phase retardation measurement for a PM fibre
δ ( y)
as a function of fibre radius y when the projected angle α is 0°, 45°, 90°, and 135°.10
Figure 6 – Measured projected phases of a PM fibre for various projected
δ ( y,α)
angles as a function of fibre radius .11
Figure 7 – Calculated 2-D stress profile of a PM fibre .11

TR 62469 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
______________
GUIDANCE FOR RESIDUAL STRESS MEASUREMENT
OF OPTICAL FIBRE
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 62469, which is a technical report, has been prepared by subcommittee 86A: Fibres
and cables, of IEC technical committee 86: Fibre optics.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
86A/1143/DTR 86A/1148/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.

– 4 – TR 62469 © IEC:2007(E)
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 62469 © IEC:2007(E) – 5 –
GUIDANCE FOR RESIDUAL STRESS MEASUREMENT
OF OPTICAL FIBRE
1 Scope
The measurement of residual stress distribution in an uncoated glass optical fibre is
considered to be important as it affects critical fibre parameters such as refractive index,
intrinsic polarization mode dispersion, mode field diameter and dispersion. The optical
polarimetric method is a well-established technique to measure the residual stress of an
optical material. This technical report describes a transverse polarimetric method to measure
the residual stress profile of any type of optical fibre.
The principle and detailed procedure for measuring the optical transverse stress profile of a
fibre, which is cylindrically symmetric, is described in detail. It is based on a polariscope,
which is constructed with a fixed polarizer, a quarter-wave plate and an analyzer. An optical
tomographic technique is also described for measuring the stress profile of a fibre with a
cylindrically non-symmetric structure.
2 Justification of measurement
Residual stress in an optical fibre is induced by the combination of the fibre construction and
the drawing process. The stress information is important because it affects many important
parameters of an optical fibre due to the following reasons.
• Temperature dependent changes of fibre parameters are larger for a fibre with larger
residual stress, and these are responsible for the statistical behaviour of polarization
1)
mode dispersion (PMD) changes in deployed fibre links. (See references [10-12].)
• The variation of important fibre parameters such as chromatic dispersion, mode field
diameter, PMD depends on the intrinsic residual stress of an optical fibre. (See references
[13-17].)
• The asymmetric residual stress profile of a fibre causes fibre curl, which affects cleaving
quality for an optical fibre ribbon.
• The asymmetric residual stress of a fibre is a major cause of the intrinsic PMD of an
optical fibre. (See references [18-20].)
• Excessive residual stress can lead to core cracking that might be seen in, for example, the
preparation of the ends for connectors.
• The design of polarization retaining fibres normally involves inducing a non-symmetric
stress field. This measurement can be used to confirm these designs.
Much progress has been made in measuring the residual stress profile of an optical fibre (see
references [1-9]) such that spatial resolution can be as small as 0,6 µ and accuracy in
measuring stress can be as low as 0,4 MPa.
Depending on the application, either one- or two-dimensional stress data may be needed.
This document describes methods by measuring the polarization rotation of a transversely
exposed laser light across a fibre cross-section using a polarimetric method.
—————————
1)
Figures in square brackets refer to the Bibliography.

– 6 – TR 62469 © IEC:2007(E)
3 Apparatus
3.1 General
An optical transverse phase retardation measurement method is used to determine the
residual stresses in a fibre. Figure 1 shows a simple polariscopic phase retardation
measurement setup consisting of a polarizer, fibre sample, Babinet variable phase
compensator, and an analyzer. Stressed material shows stress-induced birefringence for light
propagating through the medium. By measuring the polarization dependent phase retardation
of light transmitted through a sample, the stress can be measured.
3.2 Light source
The light source shall be a laser with a specified optical wavelength and narrow optical
spectrum bandwidth (maximum 2 nm at FWHM [full width at half maximum]). A collimated
laser light source is recommended. When a laser is used, a rotating diffuser is recommended
in order to remov
...