IEC PAS 61300-3-43:2006

Fibre optic interconnecting devices and passive components - Basic test and measurement procedures - Part 3-43: Examinations and measurements - Mode transfer function measurement for fibre optic sources

This part of IEC 61300 describes the method for measuring the mode transfer function (MTF) to be used in characterizing the launch conditions for measurements of attenuation and or return loss of multimode passive components, according to IEC 61300-1 and IEC 61300-3-4. The MTF may be measured at the operational wavelengths.

General Information

• Status: Replaced
• Publication Date: 12-Feb-2006
• ICS: 33.180.20 - Fibre optic interconnecting devices
• Technical Committee: SC 86B - Fibre optic interconnecting devices and passive components
• Drafting Committee: WG 4 - TC 86/SC 86B/WG 4
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 22-Jan-2009

Relations

• Replaced By: IEC 61300-3-43:2009 - Fibre optic interconnecting devices and passive components - Basic test and measurement procedures - Part 3-43: Examinations and measurements - Mode transfer function measurement for fibre optic sources
• Effective Date: 05-Sep-2023

Standards Content (Sample)

PUBLICLY
IEC
AVAILABLE
PAS 61300-3-43
SPECIFICATION
First edition
Pre-Standard
2006-02
Fibre optic interconnecting devices
and passive components –
Basic test and measurement procedures –
Part 3-43:
Examinations and measurements –
Mode transfer function measurement
for fibre optic sources
Reference number
IEC/PAS 61300-3-43:2006(E)
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PUBLICLY
IEC
AVAILABLE
PAS 61300-3-43
SPECIFICATION
First edition
Pre-Standard
2006-02
Fibre optic interconnecting devices
and passive components –
Basic test and measurement procedures –
Part 3-43:
Examinations and measurements –
Mode transfer function measurement
for fibre optic sources
 IEC 2006  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.
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Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
R
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – PAS 61300-3-43  IEC:2006(E)

CONTENTS
FOREWORD.3

1 Scope .5

2 Normative references .5

3 General description .5

4 Theory .5

4.1 Alternative method.7
4.2 Mode power distribution.7
4.3 Relative power distribution.8
4.4 Constraints.9
5 Apparatus.10
5.1 General .10
5.2 Test sample.10
5.3 Sample positioning device .10
5.4 Optical system.10
5.5 Camera .10
5.6 Video digitizer .11
5.7 Calibration.11
6 Procedure .11
6.1 Mounting and aligning the sample .11
6.2 Optimization .11
6.3 Acquiring the data .12
7 Calculations .12
7.1 Background level subtraction. .12
7.2 Location of the centroid of the intensity profile.12
7.3 Differentiating the intensity profile .13
7.4 Computing the MTF .14
8 Results.15
Annex A (normative) Launch modal distribution for multimode attenuation
measurements.16
Bibliography .18

PAS 61300-3-43  IEC:2006(E) – 3 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
FIBRE OPTIC INTERCONNECTING DEVICES

AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 3-43: Examinations and measurements –

Mode transfer function measurement for fibre optic sources

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 61300-3-43 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/2199/NP 86B/2257/RVN
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.

– 4 – PAS 61300-3-43  IEC:2006(E)

This PAS shall remain valid for an initial maximum period of three years starting from

2006-02. 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.

PAS 61300-3-43  IEC:2006(E) – 5 –

FIBRE OPTIC INTERCONNECTING DEVICES

AND PASSIVE COMPONENTS –
BASIC TEST AND MEASUREMENT PROCEDURES –

Part 3-43: Examinations and measurements –

Mode transfer function measurement for fibre optic sources

1 Scope
This part of IEC 61300 describes the method for measuring the mode transfer function (MTF)
to be used in characterizing the launch conditions for measurements of attenuation and or
return loss of multimode passive components, according to IEC 61300-1 and IEC 61300-3-4.
The MTF may be measured at the operational wavelengths.
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 61300-1, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 1: General and guidance
IEC 61300-3-4, Fibre optic interconnecting devices and passive components – Basic test and
measurement procedures – Part 3-4: Examination and measurements – Attenuation
3 General description
The modal distribution launched into multimode fibre can vary widely with different light
sources. This variation in launched modal distribution can result in significant differences in
measured attenuation in the same component. The MTF test method gives information about
the launched modal distribution (LMD) condition in a measured component. The MTF test
method is based on a measurement of the near-field intensity distribution in the fibre [1], [2] .
4 Theory
For a fibre with a power-law index profile n(r), given by
0,5
α
 
r r
   
 
n(r)= n 1− 2∆   ≤ 1 (1)
a a
 
   
 
where
a is the fibre core radius;
α is the profile factor (α = 2 for a parabolic profile);
∆ is the relative index difference, given by

—————————
Figures in square brackets refer to the Bibliography.

– 6 – PAS 61300-3-43  IEC:2006(E)

2 2
n − n
1 2
∆= (2)
2n
where
n is the index at the fibre centre;
n is the cladding index.
The near-field intensity profile in the fibre I(r) may be determined from an integration of the
mode transfer function MTF, δ, in the fibre, as follows (ignoring constants):

∆
I(r)= MTF(δ ).dδ (3)
∫
α
r
∆()
a
where
δ is the normalized propagation constant;
r/a is the normalized radial position.
Differentiating both sides gives the MTF as follows (ignoring constants):

 dI(r) 1 
MTF(δ )= ⋅ (4)
 
α−1
α
dr
 r  r
δ=∆()
a
The MTF is usually plotted in terms of the principal mode number, m, divided by the maximum
principal mode number, M, where
(2+α ) (2+α )
2α 2
m δ r
   
= = (5)
   
M ∆ a
   
The term, m/M, is usually referred to as the relative mode number, or the normalized mode
number.
The maximum principle mode number, M, is given by
α  n 2πa
M= ∆ (6)
 
α+ 2 λ
 
A typical normalized MTF plot is shown in Figure 1, where it can be se
...