IEC 60876-1:2014

Fibre optic interconnecting devices and passive components - Fibre optic spatial switches - Part 1: Generic specification

IEC 60876-1:2014 applies to fibre optic switches possessing all of the following general features:
- they are passive in that they contain no optoelectronic or other transducing elements;
- they have one or more ports for the transmission of optical power and two or more states in which power may be routed or blocked between these ports;
- the ports are optical fibres or fibre optic connectors. This fifth edition cancels and replaces the fourth edition that was published in 2012 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- addition of definitions for the terms for "normally-on;
- "normally-off" and "crosstalk";
- addition of a new Annex E. Keywords: fibre optic switches, transmission of optical power, fibre optic connectors

Dispositifs d'interconnexion et composants passifs à fibres optiques - Commutateurs spatiaux à fibres optiques - Partie 1: Spécification générique

L'IEC 60876-1:2014 s'applique aux commutateurs à fibres optiques possédant toutes les caractéristiques générales suivantes:
- ils sont passifs dans la mesure où ils ne contiennent aucun élément optoélectronique ou autre élément transducteur;
- ils ont au moins un port de transmission de la puissance optique et au moins deux états dans lesquels la puissance peut passer ou être bloquée entre ces ports;
- les ports sont des fibres optiques ou des connecteurs à fibres optiques. Cette cinquième édition annule et remplace la quatrième édition parue en 2012. Elle constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- l'ajout de définitions pour les termes "conducteur par défaut", "isolé par défaut" et "diaphonie";
- l'ajout d'une nouvelle Annexe E. Mots clés: commutateurs à fibres optiques, transmission de la puissance optique, connecteurs à fibres optiques

General Information

• Status: Published
• Publication Date: 21-Aug-2014
• ICS: 17.140.50 - Electroacoustics
• ICS: 33.180.20 - Fibre optic interconnecting devices
• Technical Committee: SC 86B - Fibre optic interconnecting devices and passive components
• Drafting Committee: WG 7 - TC 86/SC 86B/WG 7
• Current Stage: PPUB - Publication issued
• Start Date: 22-Aug-2014
• Completion Date: 15-Nov-2014

Relations

• Revises: IEC 60876-1:2012 - Fibre optic interconnecting devices and passive components - Fibre optic spatial switches - Part 1: Generic specification
• Effective Date: 05-Sep-2023

Overview

IEC 60876-1:2014 is an international standard published by the International Electrotechnical Commission (IEC) that defines the generic specification for fibre optic spatial switches. These switches are passive fibre optic interconnecting devices and components used extensively in optical communication networks. The fifth edition of this standard updates and replaces the previous 2012 version, introducing new definitions and enhancements that improve clarity and application.

This standard applies to fibre optic switches characterized by the following key features:

• They are fully passive, containing no optoelectronic or transducing elements.
• Provide one or more ports specifically for optical power transmission.
• Support two or more switch states, allowing power to be routed or blocked between ports.
• Use optical fibres or fibre optic connectors as ports.

IEC 60876-1:2014 ensures global interoperability and quality assurance for manufacturers, designers, and users involved in fibre optic spatial switching technology.

Key Topics

The standard covers comprehensive topics including:

• Definitions and Terminology: Addition of clear definitions for critical terms such as normally-on, normally-off, and crosstalk to standardize communication across the industry.
• Classification and Types: Detailed categorization of fibre optic switches by type, style, and variant to guide product specification and selection.
• Performance Parameters: Specifications on essential performance metrics like switching time, latency, insertion loss, and isolation.
• Design and Construction: Guidelines on materials, workmanship, and quality control to ensure product reliability, safety, and functionality.
• Documentation and Marking: Requirements for detailed documentation including symbols, drawings, test reports, and proper identification marking for traceability.
• Safety and Storage: Recommendations for safe handling, packaging, and storage conditions to preserve device integrity.
• Annexes: Informative annexes describing different technologies behind spatial switches such as magneto-optic (MO), mechanical, micro-electromechanical systems (MEMS), and thermo-optic (TO) switches, providing practical insights into the operational principles.

Applications

IEC 60876-1:2014 is applicable in various practical scenarios where optimal management of optical signals is crucial. Typical applications include:

• Telecommunications: Used in optical switching networks to route signals without electrical conversion, enhancing network speed and reducing latency.
• Data Centers: Enables dynamic reconfiguration of fibre connections for improved flexibility and reliability in large-scale server environments.
• Optical Testing and Measurement: Provides reliable switching in automated test setups to evaluate fibre optic components and systems.
• Broadcast and Military Systems: Integrated in systems requiring secure, high-performance optical routing with minimal power consumption.
• Research and Development: Supports experimental setups needing precise and low-loss fibre optic switching capabilities.

The standard’s emphasis on passive spatial switching devices ensures minimal signal degradation and power loss, which is critical for high-bandwidth, high-reliability optical networks.

Related Standards

IEC 60876-1:2014 is part of a broader family of standards addressing fibre optic interconnecting devices and passive components. Related IEC standards include:

• IEC 60876 Series: Additional parts of the series that focus on specific aspects or advanced requirements of fibre optic spatial switches.
• IEC 61754 Series: Standards for fibre optic connector interfaces ensuring mechanical compatibility.
• IEC 61300 Series: Standards on fibre optic interconnecting devices and passive components-basic test and measurement procedures.
• IEC 60793: Pertains to optical fibre specifications, critical for ensuring fibre compatibility with spatial switching components.

Adhering to IEC 60876-1 alongside these complementary standards enables comprehensive compliance with international requirements for optical networking hardware, ensuring component interoperability and quality.

---

Keywords: fibre optic switches, optical power transmission, fibre optic connectors, passive fibre optic spatial switches, IEC 60876-1, fibre optic interconnecting devices, optical network components, switching time, optical signal routing.

Standards Content (Sample)

IEC 60876-1 ®
Edition 5.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre optic interconnecting devices and passive components –
Fibre optic spatial switches –
Part 1: Generic specification
Dispositifs d'interconnexion et composants passifs à fibres optiques –
Commutateurs spatiaux à fibres optiques –
Partie 1: Spécification générique

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IEC 60876-1 ®
Edition 5.0 2014-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Fibre optic interconnecting devices and passive components –

Fibre optic spatial switches –

Part 1: Generic specification
Dispositifs d'interconnexion et composants passifs à fibres optiques –

Commutateurs spatiaux à fibres optiques –

Partie 1: Spécification générique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
V
CODE PRIX
ICS 33.180.20 ISBN 978-2-8322-1791-7

– 2 – IEC 60876-1:2014 © IEC 2014
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references. 6
3 Terms and definitions . 7
3.1 Basic terms and definitions . 7
3.2 Component definitions . 8
3.3 Performance parameter definitions . 9
4 Requirements . 12
4.1 Classification . 12
4.1.1 General . 12
4.1.2 Type . 13
4.1.3 Style . 16
4.1.4 Variant . 17
4.1.5 Normative reference extension . 17
4.2 Documentation . 18
4.2.1 Symbols . 18
4.2.2 Specification system . 18
4.2.3 Drawings . 20
4.2.4 Test and measurement . 20
4.2.5 Test reports . 21
4.2.6 Instructions for use . 21
4.3 Standardization system . 21
4.3.1 Interface standards . 21
4.3.2 Performance standards . 21
4.3.3 Reliability standards . 22
4.3.4 Interlinking . 22
4.4 Design and construction . 24
4.4.1 Materials . 24
4.4.2 Workmanship . 24
4.5 Quality . 24
4.6 Performance . 24
4.7 Identification and marking. 24
4.7.1 General . 24
4.7.2 Variant identification number . 24
4.7.3 Component marking . 25
4.7.4 Package marking . 25
4.8 Packaging . 25
4.9 Storage conditions . 25
4.10 Safety . 25
Annex A (informative) Example of magneto-optic effect (MO) switch technologies . 27
Annex B (informative) Example of mechanical switch technologies . 28
Annex C (informative) Example of micro-electromechanical system (MEMS) switch
technologies . 29
Annex D (informative) Example of thermo-optic effect (TO) technologies . 30
Annex E (informative) Summary of definitions on switching time . 33
Bibliography . 34

Figure 1 – Representation of latency time, rise time, fall time, bounce time and
switching time . 12
Figure 2 – Single-pole, single-throw switch . 14
Figure 3 – Transfer matrix for one input port and one output port . 14
Figure 4 – Single-pole, throw switch . 14
Figure 5 – Transfer matrix for one input port and N output ports . 14
Figure 6 – N-port matrix switch. 15
Figure 7 – Transfer matrix for N-ports switch . 15
Figure 8 – Four-port switch without crossover . 16
Figure 9 – Four-port switch with crossover . 16
Figure 10 – Configuration A, a device containing integral fibre optic pigtails without
connectors . 17
Figure 11 – Configuration B, a device containing integral fibre optic pigtails, with a
connector on each pigtail . 17
Figure 12 – Configuration C, a device containing a fibre optic connector as an integral
part of the device housing . 17
Figure 13 – Standards . 23
Figure A.1 – Example of 1×2 MO switch . 27
Figure B.1 – Example of mechanical switch (mirror driving type) . 28
Figure B.2 – Example of mechanical switch (fibre driving type) . 28
Figure C.1 – Example of MEMS switch . 29
Figure D.1 – Example of TO switch . 30
Figure D.2 – Output power of TO switch . 31
Figure D.3 – Example of switching response of TO switch . 31
Figure D.4 – 1 × N and N × N examples of TO switch . 32

Table 1 – Example of a typical switch classification . 13
Table 2 – Transfer matrix of a four-port switch without crossover . 15
Table 3 – Transfer matrix of a four-port switch with crossover . 16
Table 4 – IEC specification structure . 19
Table 5 – Standards interlink matrix . 24
Table E.1 – Summary of definitions of latency time . 33
Table E.2 – Summary of the definitions of rise time . 33
Table E.3 – Summary of the definitions of fall time . 33

– 4 – IEC 60876-1:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC INTERCONNECTING DEVICES
AND PASSIVE COMPONENTS –
FIBRE OPTIC SPATIAL SWITCHES –

Part 1: Generic specification
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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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.
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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.
International Standard IEC 60876-1 has been prepared by subcommittee SC86B: Fibre optic
interconnecting devices and passive components, of IEC technical committee 86: Fibre optics.
This fifth edition cancels and replaces the fourth edition that was published in 2012 and
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of definitions for the terms for "normally-on; "normally-off" and "crosstalk";
b) addition of a new Annex E.
The text of this standard is based on the following documents:
CDV Report on voting
86B/3713/CDV 86B/3788/RVC
Full information on the voting for the approval of this standard 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.
A list of all the parts in the IEC 60876 series, published under the general title Fibre optic
interconnecting devices and passive components – Fibre optic spatial switches can be found
on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 60876-1:2014 © IEC 2014
FIBRE OPTIC INTERCONNECTING DEVICES
AND PASSIVE COMPONENTS –
IBRE OPTIC SPATIAL SWITCHES –
Part 1: Generic specification
1 Scope
This part of IEC 60876 applies to fibre optic switches possessing all of the following general
features:
– they are passive in that they contain no optoelectronic or other transducing elements;
– they have one or more ports for the transmission of optical power and two or more states
in which power may be routed or blocked between these ports;
– the ports are optical fibres or fibre optic connectors.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60027 (all parts), Letter symbols to be used in electrical technology
IEC 60050-731, International Electrotechnical Vocabulary – Chapter 731: Optical fibre
communication
IEC 60617 (all parts), Graphical symbols for diagrams (available at
)
IEC 60695-11-5, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method –
Apparatus, confirmatory test arrangement and guidance
IEC 60825-1, Safety of laser products – Part 1: Equipment classification and requirements
IEC 61300 (all parts), Fibre optic interconnecting devices and passive components – Basic
test and measurement procedures
IEC TR 61930, Fibre optic graphical symbology
IEC 62047-1, Semiconductor devices – Micro-electromechanical devices – Part 1: Terms and
definitions
ISO 129-1, Technical drawings – Indication of dimensions and tolerances – Part 1: General
principles
ISO 286-1, Geometrical product specifications (GPS) – ISO code system for tolerances on
linear sizes – Part 1: Basis of tolerances, deviations and fits

ISO 1101, Geometrical product specifications (GPS) – Geometrical tolerancing – Tolerances
of form, orientation, location and run-out
ISO 8601, Data elements and interchange formats – Information interchange –
Representation of dates and times
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-731, together
with the following, apply.
3.1 Basic terms and definitions
3.1.1
port
optical fibre or fibre optic connector attached to a passive component for the entry and/or exit
of optical power
3.1.2
transfer matrix
optical properties of a fibre optic switch can be defined in a n × n matrix of coefficients (n is
the number of ports)
Note 1 to entry: The T matrix represents the on-state paths (worst-case transmission) and the T° matrix
represents the off-state paths (worst-case isolation).
3.1.3
transfer coefficient
element t or t° of the transfer matrix
ij ij
Note 1 to entry: Each transfer coefficient t is the worst-case (minimum) fraction of power transferred from port i
ij
to port j for any state with path ij switched on. Each coefficient t° is the worst-case (maximum) fraction of power
ij
transferred from port i to port j for any state with path ij switched off.
3.1.4
logarithmic transfer matrix
a = –10 log t
ij 10 ij
where
a is the optical power reduction in decibels out of port j with unit power into port i, i.e.

ij
t is the transfer coefficient
ij
Note 1 to entry: Similarly, for the off state, a° = –10 log t° .
ij 10 ij
3.1.5
switch state
particular optical configuration of a switch, whereby optical power is transmitted or blocked
between specific ports in a predetermined manner
3.1.6
actuation mechanism
physical means (mechanical, electrical, acoustic, optical, etc.) by which a switch is designed
to change between states
3.1.7
actuation energy
input energy required to place a switch in a specific state

– 8 – IEC 60876-1:2014 © IEC 2014
3.1.8
blocking
inability to establish a connection from a free input port to a free output port due to the
existence of some other established connection
Note 1 to entry: Blocking and various degrees of non-blocking operation functionalities are of various types:
“Strict-sense non-blocking” refers to a switch matrix in which it is always possible to establish a connection
between any free input port and any free output port, irrespective of previously established connections.
“Wide-sense non-blocking” refers to a matrix in which it is always possible to establish a desired connection
provided that some systematic procedure is followed in setting up connections. Some multistage switching
architectures fall into this category.
“Rearrangeably non-blocking” refers to a switch matrix in which any free input port can be connected to any free
output port provided that other established connections are unconnected and then reconnected as part of making
the new connection.
3.1.9
normally on
condition where a port pair is in a conducting state when there is no actuation energy applied
for a non-latching switch
3.1.10
normally off
condition where a port pair is in an isolated state when there is no actuation energy applied
for a non-latching switch
3.2 Component definitions
3.2.1
optical switch
passive component processing one or more ports which selectively transmits, redirects or
blocks optical power in an optical fibre transmission line
3.2.2
latching switch
switch that maintains its last state and specified performance level when the actuation energy
which initiated the change is removed
3.2.3
non-latching switch
switch that reverts to a home state or undefined state when the actuation energy which
initiated a change is removed
3.2.4
magneto-optic effect switch
MO switch
optical switch which uses the magneto-optic effect (phenomenon of polarization state change
in transmitted light and reflected light due to a magnetic field)
Note 1 to entry: Annex A shows an example of magnet-optic effect swich technologies.
3.2.5
mechanical switch
optical switch which realises the switching function by driving of the movable part
Note 1 to entry: Annex B shows an example of mechanical swich technologies.

3.2.6
micro-electromechanical system switch
MEMS switch
optical switch using MEMS technology, as defined in IEC 62047-1
Note 1 to entry: Annex C shows example of micro-mechanical system swich technologies.
3.2.7
thermo-optic effect switch
TO switch
optical switch which uses the thermo-optic effect (phenomenon of refractive index change
caused by temperature variation)
Note 1 to entry: Annex D shows an example of thermo-optic effect swich technologies.
3.3 Performance parameter definitions
3.3.1
operating wavelength
λ
nominal wavelength at which a passive component is designed to operate with the specified
performance
3.3.2
insertion loss
element a (where i ≠ j) of the logarithmic transfer matrix
ij
Note 1 to entry: It is the reduction in optical power between an input and output port of a passive component
expressed in decibels and is defined as follows:
a = –10 log (P /P )
ij 10 j i
where
P is the optical power launched into the input port, and
i
P is the optical power received from the output port.
j
Note 2 to entry: The insertion loss values depend on the state of the switch.
3.3.3
return loss
element a (where i = j) of the logarithmic transfer matrix
ij
Note 1 to entry: It is the fraction of input power that is returned from a port of a passive component and is defined
as follows:
RL = –10 log (P /P )
i 10 refl i
where
P is the optical power launched into a port, and
i
P is the optical power received back from the same port.
refl
Note 2 to entry: The return loss values depend on the state of the switch.
3.3.4
crosstalk
ratio of the output power of the isolated input port to the output power of the conducting input
port for an output port
3.3.5
latency time
3.3.5.1
latency time
t
l
– 10 – IEC 60876-1:2014 © IEC 2014
elapsed time for the output power of a
specified output port to reach 10 % of its steady-state value from the time the actuation
energy is applied, when switching from an isolated state to conducting state, normally-off for a
non-latching switch, or a latching switch
SEE: Figure 1.
3.3.5.2
latency time
t ’
l

elapsed time for the output power of a specified output port to reach 90 % of its steady-state
value from the time the actuation energy is removed. when switching from a conducting state
to isolated state, normally-off for a non-latching switch
SEE: Figure 1.
3.3.5.3
latency time
t ’
l
elapsed time when
the output power of a specified output port reaches 90 % of its steady-state value from the
time the actuation energy is applied, when switching from a conducting state to isolated state,
for a latching switch
SEE: Figure 1.
Note 1 to entry: See Annex E.
3.3.6
rise time
elapsed time when the output power of the specified output port rises from 10 % of the
steady-state value to 90 % of the steady-state value
3.3.7
fall time
elapsed time when the output power of the specified output port falls from 90 % of the steady-
state value to 10 % of the steady-state value
3.3.8
bounce time
3.3.8.1
bounce time
t
b
elapsed time when the output power of a
specified output port maintains between 90 % and 110 % of its steady-state value from the
first time the output power of a specified output port reaches to 90 % of its steady-state value
SEE: Figure 1.
3.3.8.2
bounce time
t ’
b
elapsed time when the output power of a
specified output port maintains between 0 % and 10 % of its steady-state value from the first
time the output power of a specified output port reaches 10 % of its steady-state value
SEE: Figure 1.
3.3.9
switching time
3.3.9.1
switching time
t
s
switching time is defined as follows:
t = t + t+ t
s l r b
where
t is the latency time;
l
t is the rise time;
r
t is the bounce time.
b
3.3.9.2
switching time
t ’
s
switching time is defined as follows:
t ’ = t ’ + t + t ’
s l f b
where
t ’ is the latency time;
l
t is the fall time;
f
t ’ is the bounce time.
b
3.3.10
switching time matrix
matrix of coefficients in which each coefficient S is the longest switching time to turn path ij
ij
on or off from any initial state

Actuation energy supply
Output port power
110 % of steady-state
Power
Steady-state
90 % of steady-state
10 % of steady-state
t ’
t t ’ t b
t Time
l t l f
r b
t ’
t s
s
t t ’  switching time
s, s
t t ’  latency time
l, l
t  rise time
r
t  fall time
f
tb, tb’  bounce time
IEC
Figure 1a – Non-latching switch, normally off

– 12 – IEC 60876-1:2014 © IEC 2014
Actuation energy supply Actuation energy supply
Output port power
110 % of steady-state
Power
Steady-state
90 % of steady-state
10 % of steady-state
t t ’
t t ’ t b Time
l t l f
r
b
t ’
t
s
s
t t ’  switching time
s, s
t t ’  latency time
l, l
t  rise time
r
t  fall time
f
t , t ’   bounce time
b b
IEC
Figure 1b – Non-latching switch, normally on

Output port power
Actuation energy supply
110 % of steady-state
Power
Steady-state
90 % of steady-state
10 % of steady-state
t ’
t t t ’ t b Time
l t l f
r
b
t ’
t
s
s
t t ’  switching time
s, s
t t ’  latency time
l, l
t  rise time Actuation energy supply
r
t  fall time
f
t , t ’  bounce time
b b
IEC
Figure 1c – Latching switch
Figure 1 – Representation of latency time, rise time, fall time, bounce time and
switching time
Note 1 to entry: If, for any reason, the steady-state power of the isolated state is not zero, all the power levels
leading to the definitions of latency time, rise time, fall time, bounce time and, thus, of switching time, should be
normalized, subtracting from them the steady-state power of the isolated state, before applying such definitions.
4 Requirements
4.1 Classification
4.1.1 General
Fibre optic spatial switches shall be classified based on the following:

– type;
– style;
– variant;
– assessment level;
– normative reference extensions.
Table 1 is an example of a switch classification.
Table 1 – Example of a typical switch classification
Type:
1×2 mechanical switch
– Configuration B
Style:
– IEC type A1 a fibre
– F-SMA connector
Variants: Means of mounting
Assessment level: A
Normative reference extensions: ……………………………

4.1.2 Type
4.1.2.1 General
Switches are divided into types by their actuation mechanism, latching and topology (optical
switching function).
There are multiple actuation mechanisms of switches. The following is a non-exhaustive list of
examples of current technologies used in the industry:
– magneto-optic effect (MO);
– mechanical;
– micro-electromechanical system (MEMS);
– thermo-optic effect (TO).
Switches are divided into two types based on the latching function as follows:
– latching switch;
– non-latching switch.
There are an essentially infinite number of possible topologies. Each topology is illustrated by
a schematic diagram and defined by a unique transfer matrix.
The following device topologies include only those which are in common use within the
industry at present. The schematic diagrams which follow do not necessarily correspond to
the physical layout of the switch and its ports.
The examples given in 4.1.2.2 to 4.1.2.4 apply to unidirectional switches only, where t ≠ t .

ij ji
For bi-directional switches, t = t in each transfer matrix below.
ij ji
4.1.2.2 Single-pole, single-throw switch
Figure 2 shows a single-pole, single-throw switch.

– 14 – IEC 60876-1:2014 © IEC 2014
Off
1 2
On
IEC
Figure 2 – Single-pole, single-throw switch
This switch has one input port and one output port. Figure 3 shows the transfer matrix
describing the device.
t t
 
11 21
T=
 
t t
 12 22
IEC
Figure 3 – Transfer matrix for one input port and one output port
Ideally, t is 1 and the other coefficients are 0 when the switch is on. When the switch is off,
all coefficients are 0.
4.1.2.3 Single-pole, N-throw switch
Figure 4 shows a single-pole, N-throw switch.
.
.
.
.
N + 1
IEC
Figure 4 – Single-pole, throw switch
This switch has one input port and N output ports. Figure 5 shows the transfer matrix
describing the device.
t t ⋅ ⋅ ⋅ t
 
11 12 1 N+1
 
t
 
 
⋅
T=
 
⋅ t ⋅
 ij 
 
⋅
 
t ⋅ t
 
N+11 N+1N+1
 
IEC
Figure 5 – Transfer matrix for one input port and N output ports
Ideally, in the first position of the switch, t is 1 and the other coefficients are 0. In the
generic i-th position of the switch, the t transfer coefficient is 1 and the others are 0.
1 i+1
4.1.2.4 N-port matrix switch
Figure 6 shows an N-port matrix switch.
. . . .
1 2 3 N
IEC
Figure 6 – N-port matrix switch
This switch has N ports. Figure 7 shows the transfer matrix describing the device.

 t t ⋅ ⋅ ⋅ t 
11 12 1 N
 
t
 
 
⋅
T=
 
⋅ t ⋅
 ij 
 
⋅
 
t ⋅ t
 
 N11 NN
IEC
Figure 7 – Transfer matrix for N-ports switch
A 2×2 matrix switch is a particular case with two input and two output ports.
In one type, it is possible to have four positions with the transfer coefficients t and t
14 23
always zero while t and t have the values indicated in Table 2. Figure 8 shows a four-port
13 24
switch without crossover.
Table 2 – Transfer matrix of a four-port switch without crossover
State
Transfer coefficient
1 2 3 4
t 1 0 1 0
t 1 1 0 0
– 16 – IEC 60876-1:2014 © IEC 2014
State 1
1 3
State 4
2 4
State 2
1 3
State 3
2 4
IEC
Figure 8 – Four-port switch without crossover
In another type, a four-port crossover switch or by-pass switch is described. This switch has
two input and two output ports. The transfer coefficients are indicated in Table 3. Figure 9
shows a four-port switch with crossover.
Table 3 – Transfer matrix of a four-port switch with crossover
State
Transfer coefficient
1 2
t 1 0
t 1 0
t 0 1
t 0 1
State 1
1 3
State 2
2 4
IEC
Figure 9 – Four-port switch with crossover
4.1.3 Style
Switches may be classified into styles based upon fibre type, connector type, cable type,
housing shape and dimensions and configuration.
The configuration of the switch ports is classified as shown below.
Figure 10 shows configuration A, device containing integral fibre optic pigtails without
connectors.
Switch
IEC
Figure 10 – Configuration A, a device containing integral fibre optic pigtails without
connectors
Figure 11 shows configuration B, a device containing integral fibre optic pigtails, with a
connector on each pigtail.
Switch
IEC
Figure 11 – Configuration B, a device containing integral fibre optic pigtails, with a
connector on each pigtail
Figure 12 shows configuration C, a device containing a fibre optic connector as an integral
part of the device housing.
Switch
IEC
Figure 12 – Configuration C, a device containing a fibre optic connector as an integral
part of the device housing
Configuration D is a device containing some combination of the interfacing features of the
preceding configurations.
4.1.4 Variant
The switch variant identifies those features which encompass structurally similar components.
Examples of features which define a variant include, but are not limited to the following:
– orientation of ports on housing;
– means for mounting.
4.1.5 Normative reference extension
Normative reference extensions are used to identify integrated independent standards
specifications or other reference documents into blank detail specifications.
Unless specified exception is noted, additional requirements imposed by an extension are
mandatory. Usage is primarily intended to merge associated components to form hybrid
devices, or integrated functional application requirements that are dependent on technical
expertise other than fibre optics.

– 18 – IEC 60876-1:2014 © IEC 2014
Published reference documents produced by the ITU, consistent with the scope statements of
the relevant IEC specification series may be used as extensions. Published documents
produced by other regional standardization bodies such as ANSI, CENELEC, JIS, etc., may
be referenced in a bibliography attached to the generic specification.
Some spatial switch configurations require special qualification provisions which shall not be
imposed universally. This accommodates individual component design configurations,
specialized field tooling or specific application processes. In this case, requirements are
necessary to assure repeatable performance or adequate safety and provide additional
guidance for complete product specification and they shall be defined in the relevant
specification. These extensions are mandatory whenever they are used to prepare, assemble
or install a spatial switch either for field application usage or preparation of qualification test
specimens. The relevant specification shall clarify all stipulations. However, design and style-
dependent extensions shall not be imposed universally.
In the event of conflicting requirements, precedence, in descending order, shall be the generic
specification over mandatory extension, over blank detail, over detail specification, over
application-specific extension.
Examples of requirements for normative extensions are as follows:
– Some commercial or residential building applications may require direct reference to
specific safety codes and regulations or incorporate other specific material flammability or
toxicity requirements for specialized locations.
– Specialized field tooling may require an extension to implement specific ocular safety,
electrical shock, burn hazard avoidance requirements, or require isolation procedures to
prevent potential ignition of combustible gases.
4.2 Documentation
4.2.1 Symbols
Graphical and letter symbols shall, whenever possible, be taken from the IEC 60027 series,
the IEC 60617 series and from IEC TR 61930.
4.2.2 Specification system
4.2.2.1 General
This specification is part of the IEC specification system. Subsidiary specifications shall
consist of blank detail specifications and detail specifications. This system is shown in Table 4.
There are no sectional specifications for switches.

Table 4 – IEC specification structure
Specification Examples of information Applicable to
level to be included
Basics Assessment system rules Two or more component families or sub-
families
Inspection rules
Optical measurement methods
Environmental test methods
Sampling plans
Identification rules
Marking standards
Dimensional standards
Terminology
Symbol standards
Preferred number series
SI units
Generic Specific terminology Component family
Specific symbols
Specific units
Preferred values
Marking
Quality assessment procedures
Selection of tests
Qualification approval procedures
Capability approval procedures
Blank detail Quality conformance test schedule Groups of types having a common test
schedule
Inspection requirements
Information common to a number of types
Detail Individual values Individual type
Specific information
Completed quality conformance test
schedules
4.2.2.2 Blank detail specification
Blank detail specifications are not, by themselves, a specification level. They are associated
with the generic specification.
Each blank detail specification shall contain:
– the minimum mandatory test schedules and performance requirements;
– one or more assessment levels;
– the preferred format for stating the required information in the detail specification;
– in case of hy
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