IEC PAS 61300-3-38:2007

PUBLICLY
IEC
AVAILABLE
PAS 61300-3-38
SPECIFICATION
First edition
Pre-Standard
2007-04
Fibre optic interconnecting devices
and passive components –
Basic test and measurement procedures –

Part 3-38:
Group delay and chromatic dispersion
Reference number
IEC/PAS 61300-3-38:2007(E)
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PUBLICLY
IEC
AVAILABLE
PAS 61300-3-38
SPECIFICATION
First edition
Pre-Standard
2007-04
Fibre optic interconnecting devices
and passive components –
Basic test and measurement procedures –

Part 3-38:
Group delay and chromatic dispersion

PRICE CODE
Commission Electrotechnique Internationale
U
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – PAS 61300-3-38 © IEC:2007(E)
CONTENTS
FOREWORD.4
1 Scope .6
2 Normative references .6
3 Terms, definitions and abbreviations .6
4 General description .7
5 Apparatus.7
5.1 Modulation phase method .7
5.1.1 Variable wavelength source.8
5.1.2 Tracking filter.8
5.1.3 Reference branching device (RBD1, 2) .8
5.1.4 Wavelength monitor .9
5.1.5 Device under test (DUT).9
5.1.6 Detector D1, D2 (optional).9
5.1.7 RF generator .10
5.1.8 Amplitude modulator .10
5.1.9 Phase comparator.10
5.1.10 Temporary joints (TJ1-TJ2) .10
5.1.11 Polarization controller .10
5.1.12 Reference jumper .10
5.2 Swept wavelength interferometry method .10
5.2.1 Tunable laser source (TLS) .11
5.2.2 Wavelength monitor .12
5.2.3 Reference branching devices (RBD1, 2, 3) .12
5.2.4 Detectors.12
5.2.5 Polarization controller .12
5.2.6 Polarization analyser.12
6 Measurement procedure .12
6.1 Modulation phase shift method.13
6.1.1 Measurement principle .13
6.1.2 RF modulation frequency .13
6.1.3 Test sequence .15
6.1.4 Calculation of group delay.15
6.1.5 Measurement window.15
6.2 Swept wavelength interferometry method .17
6.2.1 Measurement principle .17
6.2.2 Test sequence .17
6.2.3 Calculations of group delay .18
7 Analysis .20
7.1 Noise reduction of group delay measurement .20
7.1.1 Averaging .20
7.1.2 Spectral filtering.20
7.2 Linear phase variation .20
7.3 Chromatic dispersion .20
7.3.1 Finite difference calculation.21

PAS 61300-3-38 © IEC:2007(E) – 3 –

7.3.2 Curve fit.21
8 Test results .23
Annex A (informative) Calculation of differential group delay.24
A.1 Calculation of DGD from measurements made with the MPS method at four states
of input polarization .24
A.2 Calculation of DGD from measurements made with the MPS method while
scanning the states of input polarization (“all states method”) .25
A.3 Calculation of DGD from measurements made with the SWI method .26

Figure 1 – MPS measurement method apparatus.8
Figure 2 – SWI measurement method apparatus .11
Figure 3 – Sampling at the modulation frequency .14
Figure 4 – Measurement window centred on an ITU wavelength with a defined width. .16
Figure 5 – Measurement window determined by the insertion loss curve at 3 dB .16
Figure 6 – GD and loss spectra for a 50 GHz-channel-spacing DWDM filter. .19
Figure 7 – Calculation of CD from the differentiation of the fitted GD curve with respect
to wavelength .22
Figure 8 – Fitting of a 6th order polynomial curve by least mean squares procedure to
GD data over a 25 GHz optical BW centred on the ITU frequency .22
Figure A.1 – Mueller states on Poincaré sphere.24
Figure A.2 – DGD spectrum for a 50 GHz bandpass filter measured with 30 pm
resolution BW. .27

Table A.1 – Example of Mueller set .25

– 4 – PAS 61300-3-38 © IEC:2007(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC INTERCONNECTING DEVICES
AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 3-38: Group delay and chromatic dispersion

FOREWORD
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A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 61300-3-38 has been processed by subcommittee 86B: Fibre optic interconnecting
devices and passive components, of IEC technical committee 86: Fibre optics.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document:
Draft PAS Report on voting
86B/2337/PAS 86B/2380/RVD
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.

PAS 61300-3-38 © IEC:2007(E) – 5 –

This PAS shall remain valid for an initial maximum period of three years starting from
2007-04. The validity may be extended for a single three-year period, following which it shall
be revised to become another type of normative document or shall be withdrawn.

– 6 – PAS 61300-3-38 © IEC:2007(E)
FIBRE OPTIC INTERCONNECTING DEVICES
AND PASSIVE COMPONENTS –
B
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