IEC PAS 62074-1:2007

IEC/PAS 62074-1
Edition 1.0 2007-09
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Fibre optic WDM devices –
Part 1: Generic specification
IEC/PAS 62074-1:2007(E)
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IEC/PAS 62074-1
Edition 1.0 2007-09
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Fibre optic WDM devices –
Part 1: Generic specification
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
W
ICS 33.180.01; 33.180.20 ISBN 2-8318-9283-X

– 2 – PAS 62074-1 © IEC:2007(E)

CONTENTS
FOREWORD.0H0H4

1 Scope.1H1H5

2 Normative references.2H2H5

3 Terms and definitions .3H3H6

3.1 Basic term definitions .4H4H6

3.2 Component definitions .5H5H9

3.3 Performance parameter definitions .6H6H10
4 Requirements .7H7H23
4.1 Classification.8H8H23
4.1.1 Type .9H9H23
4.1.2 Style .10H10H23
4.1.3 Variant.11H11H24
4.1.4 Assessment level.12H12H24
4.2 Documentation .13H13H25
4.2.1 Symbols.14H14H25
4.2.2 Specification system .15H15H25
4.2.3 Drawings .16H16H26
4.2.4 Measurements .17H17H27
4.2.5 Test data sheets .18H18H27
4.2.6 Instructions for use .19H19H27
4.3 Standardization system.20H20H27
4.3.1 Performance standards.21H21H27
4.3.2 Reliability standard .22H22H28
4.3.3 Interlinking.23H23H28
4.4 Design and construction .24H24H29
4.4.1 Materials.25H25H29
4.4.2 Workmanship .26H26H29
4.5 Quality.27H27H30
4.6 Performance requirements.28H28H30
4.7 Identification and marking.29H29H30
4.7.1 Variant identification number.30H30H30

4.7.2 Component marking.31H31H30
4.7.3 Package marking .32H32H30
4.8 Safety.33H33H31

Annex A (informative) Examples of fibre optic WDM device types .34H34H32
Bibliography .35H35H36

36H36H6
Figure 1 – Example of a six-port device, with two-input and four-output ports.
Figure 2 – Illustration of transfer matrix coefficient.37H37H8
Figure 3 – Example of a six-port device, with two-input and four-output ports.38H38H9
Figure 4 – Illustration of adjacent channel isolation.39H39H11
Figure 5 – Illustration of a four-wavelength bidirectional system .40H40H12
Figure 6 – Illustration of channel insertion loss variation .41H41H13

PAS 62074-1 © IEC:2007(E) – 3 –

Figure 7 – Illustration of free spectral range.42H42H14

Figure 8 – Illustration of insertion loss .43H43H15

Figure 9 – Illustration of minimum and maximum insertion loss.44H44H15

Figure 10 – Illustration of isolation wavelength.45H45H16

Figure 11 – Illustration of isolation wavelength range .46H46H16

Figure 12 – Illustration of maximum adjacent channel isolation .47H47H17

Figure 13 – Illustration of non-adjacent channel isolation .48H48H18

Figure 14 – Illustration of operating wavelength .49H49H18

Figure 15 – Illustration of operating wavelength range .50H50H19
Figure 16 – Illustration of polarization dependent centre wavelength (PDCW) .51H51H19
Figure 17a – At the band edges.52H52H21
Figure 17b – In-band.53H53H21
Figure 17 – Illustration of ripple .54H54H21
Figure 18 – Illustration of X-dB bandwidth.55H55H22
Figure 19 – Wavelength-selective branching device.56H56H23
Figure 20 – Wavelength-selective branching device.57H57H24
Figure 21 – Wavelength-selective branching device.58H58H24
Figure 22 – Wavelength-selective branching device.59H59H24
Figure A.1 – Example of a wavelength multiplexer .60H60H32
Figure A.2 – Example of a wavelength demultiplexer .61H61H33
Figure A.3 – Example of a wavelength multiplexer/demultiplexer.62H62H33
Figure A.4 – Example of a wavelength router.63H63H34
Figure A.5 – Example of wavelength channel add/drop .64H64H35

Table 1 – Three-level IEC specification structure .65H65H26
Table 2 – Standards interlink matrix .66H66H29
Table 3 – Quality assurance options .67H67H29

– 4 – PAS 62074-1 © IEC:2007(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
FIBRE OPTIC WDM DEVICES –
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
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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.
A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 62074-1 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/2516/NP 86B/2557/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.
This PAS shall remain valid for an initial maximum period of three years starting from
2007-08. 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 62074-1 © IEC:2007(E) – 5 –

FIBRE OPTIC WDM DEVICES –
Part 1: Generic specification
1 Scope
This PAS applies to fibre optic wavelength division multiplexing (WDM) devices. These have all
of the following general features:

• They are passive, in that they contain no optoelectronic or other transducing elements; but
they may use temperature control but only with the purpose of stabilizingdevice
characteristics; they exclude any optical switching function.
• They have three or more ports for the entry and/or exit of optical power, and share optical
power among these ports in a predetermined fashion depending on the wavelength.
• The ports are optical fibres or optical fibre connectors.
This document establishes uniform requirements for the following:
• Optical, mechanical and environmental properties.
• Measurement and test procedures for quality assessment.
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 60027 (all parts), Letter symbols to be used in electrical technology
IEC 60050(731): International Electrotechnical Vocabulary – Chapter 731: Optical fibre
communication
IEC 60617, International Standard Database Snapshot – Graphical symbols for diagrams
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 61300-1 (all parts), Fibre optic interconnecting devices and passive components – Basic
test and measurement procedures
IECQ 01, IEC Quality Assessment System for Electronic Components (IECQ) – Basic Rules
IECQ 001002 (all parts), IEC Quality Assessment System for Electronic Components (IECQ) –
Rules of Procedure
IEC Guide 102, Electronic components – Specification structures for quality assessment
(Qualification approval and capability approval)

ISO 129, Technical drawings – Indication of dimensions amd tolerances – General principles
ISO 286 (all parts), ISO system of limits and fits

– 6 – PAS 62074-1 © IEC:2007(E)

ISO 370, Toleranced dimensions - Conversion from inches into millimetres and vice versa

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
ITU-T Recommendation G.671:2005, Transmission characteristics of optical components and

subsystems
ITU-T Recommendation G.692:1998, Optical interfaces for multichannel systems with optical
amplifiers
3 Terms and definitions
For the purposes of this document, the definitions given in IEC 60050-731, as well as the
following, apply.
3.1 Basic term definitions
3.1.1
port
optical fibre or optical fibre connector attached to a passive component for the entry and/or exit
of the optical power (input and/or output port)
3.1.2
transfer matrix
The optical properties of a fibre optic wavelength-selective branching device can be defined in
terms of an n x n matrix of coefficients, where n is the number of ports, and the coefficients
represent the fractional optical power transferred between designated ports. Figure 1 shows
the one example of six port device which has two input ports and four output ports. The ports
are numbered sequencially. So, the possible conbinations of two ports are six by six, total 36
conbinations. These 36 conbinations are expressed by a matrix.

Inputs Outputs
1 4
Figure 1 – Example of a six-port device, with two-input and four-output ports

PAS 62074-1 © IEC:2007(E) – 7 –

In general, the transfer matrix T is :

⎡t t ⋅ ⋅ ⋅ t ⎤
11 12 1n
⎢ ⎥
t
⎢ ⎥
⎢ ⎥
⋅
T =
⎢ ⎥
⋅ t
ij
⎢
⎥
⎢ ⎥
⋅
⎢ ⎥
t t
⎢ n1 nn⎥
⎣ ⎦
where
t is the ratio of the optical power P transferred out of port j (output port) with respect to input
ij ij
power P into port i (input port), that is:
i
t = P P
ij ij i
t is a number more than zero, and less than or equal to one (0 ≤ t ≤ 1). In a wavelength-
ij ij
selective branching device the coefficient t is a function of the wavelength and may be a
ij
function of the input polarization or modal power distribution.
Single-mode fibre optic WDM devices may operate in a coherent fashion with respect to
multiple inputs. Consequently, the transfer coefficients may be affected by the relative phase
and intensity of simultaneous coherent optical power inputs at two or more ports.
The wavelength dependency of the transfer matrix coefficient should be considered. A matrix
coefficient may be expressed as t k is the wavelength number, λ For a more generic
ijk, where k.
expression, the transfer matrix is shown as follows:

3.1.3
transfer matrix coefficient
an element t of the transfer matrix (refer to Figure 2 below)
ij
– 8 – PAS 62074-1 © IEC:2007(E)

Incident power
Transfer coefficient
Transmitted power
Wavelength
Figure 2 – Illustration of transfer matrix coefficient

3.1.4
logarithmic transfer matrix
in general, the logarithmic transfer matrix is:
a a ⋅ ⋅ ⋅ a
⎡ ⎤
11 12 1n
⎢ ⎥
a
⎢ ⎥
⎢⋅ ⎥
A =⎢ ⎥
⋅ a
ij
⎢ ⎥
⎢ ⎥
⋅
⎢ ⎥
a a
⎢ n1 nn⎥
⎣ ⎦
where
a is the optical power reduction in decibels out of port j with unit power into port i, that is:
ij
a = −10 log t
ij ij
where
t is the transfer matrix coefficient.
ij
a is a positive number larger than or equal to zero. The same as the transfer matrix
ij
coefficient. A more generic expression of the logarithmic transfer matrix is shown as
follows:
Optical power
PAS 62074-1 © IEC:2007(E) – 9 –

3.1.5
conducting ports
two ports i and j between which t is nominally greater than zero at a specified wavelength.
ij
3.1.6
input/output port pair
conducting ports i and j (t nominally greater than zero) that are isolated from any other ports j
ij
(a nominally infinite)
ij
NOTE Figure 3 below shows an example of a six-port device, with two input ports and four output ports. The ports

are numbered sequentially, so that the transfer matrix is developed to show all ports and all possible combinations.

The port numbering is arbitrary.
Inputs Outputs
1 4
Figure 3 – Example of a six-port device, with two-input and four-output ports
For the example shown, if there are four operating wavelengths, then the resulting transfer matrix becomes a 6×6×4
matrix: loss at λ from port 1 to port 6 would use a . Reflectance of port 2 at λ would use a . Loss from port
1 161 4 224
5 to port 2 at λ would use a .
3 523
3.1.7
isolated ports
two ports i and j between which t is nominally zero, and a is nominally infinite at a specified
ij ij
wavelength
3.1.8
channel
another term for operating wavelength (or frequency)
3.1.9
channel spacing
centre-to-centre differences in frequency or wavelength between adjacent channels in a WDM
device
3.2 Component definitions
3.2.1
wavelength-selective branching device
passive component possessing three or more ports which shares optical power among its ports
in a predetermined fashion, without any amplification, switching, or other active modulation but
only depending on the wavelength, in the sense that at least two different wavelength ranges
are nominally transferred between two different couples of ports

– 10 – PAS 62074-1 © IEC:2007(E)

3.2.2
wavelength division multiplexer
WDM
term frequently used as a synonym for a wavelength-selective branching device

NOTE Depending on the spectral response, a WDM device may be defined either as :

− DWDM (dense WDM) device, if it is intended to operate for channel spacing equal or less than 1 000 GHz;

− CWDM (coarse WDM) device, if it is intended to operate for channel spacing less than 50 nm and greater than

1 000 GHz (about 8 nm at 1 550 nm and 5,7 nm at 1 310 nm);

− WWDM (Wide WDM) device, if it is intended to operate for channel spacing equal or greater than 50 nm.

3.2.3
wavelength multiplexer
MUX
WDM (DWDM, CWDM or WWDM) which has n input ports and one output port, and whose
function is to combine n different optical signals differentiated by wavelength from n
corresponding input ports on to a single output port
3.2.4
wavelength demultiplexer
DEMUX
WDM (DWDM, CWDM or WWDM) which has one input port and n output ports, and whose
function is to separate n different optical signals differentiated by wavelength from a single
input port to n corresponding output ports
3.2.5
interleaver
bidirectional DWDM which has three ports, and whose function is to separate n different optical
signals differentiated by wavelength from a single input port to odd channel signal to one output
port and even channel signal to the other output port alternately
3.3 Performance parameter definitions
3.3.1
crosstalk
(for WDM devices) value of the ratio between the optical power of the specified signal and all
noises
3.3.2
isolation
(for WDM devices) value of the ratio between the optical power of the specified signal and the

specified noise
3.3.3
add-drop isolation
value of the optical power reduction in decibels a between an input i, and an output port j, that
ij
is isolated at every wavelength (or frequency for a dense WDM (DWDM) device)
NOTE a is defined in 3.1.4.
ij
3.3.4
adjacent channel isolation
adjacent channel crosstalk
unidirectional (far-end) isolation with the restriction that x, the isolation wavelength number, is
restricted to the channels immediately adjacent to the (channel) wavelength number associated
with port o.
PAS 62074-1 © IEC:2007(E) – 11 –

NOTE This is illustrated in Figure 4 below. The adjacent channel crosstalk has the same meaning as adjacent

channel isolation.
NoNonn-- adj adj acent acent  AdAdjjaacceenntt CChannelhannel AdAdjjaacceenntt NoNonn-- adjadj acent acent
CChannelhannel CChannelhannel CeCennttrraall CChannelhannel CChannelhannel

CCentralentral  CeCennttrraall FFrrequencyequency CeCennttrraall CeCennttrraall
FFrrequencyequency FFrrequencyequency or Wor Wavelaveleengthngth FFrrequencyequency FFrrequencyequency

or Wor Wavelavelengthength or Wor Waavelveleengthngth or Wor Waavelveleengthngth or Wor Wavelavelengthength

0 dB0 dB
AAdjdjacacentent c channelhannel

aa
ioiocc
Isolation
Isolation
aa
ioioxx
Insertion
loss (dB)
-
-
NoNonn-- adj adj acent Cacent Channelhannel  AAdjdj acentacentCC hannelhannel CChannelhannelFF rrequency equency AAdjdjacentacentCChannelhannel NoNonn-- adj adj aacent Ccent Chhannelannel

FFrrequency Requency Raange nge  FFrrequency Requency Range ange RRange (Dange (DWWDDMM)) or or FFrrequency Requency Range ange FFrrequency Requency Raange nge
(D(DWWDDMM)) or C or Chhannelannel  (D(DWWDDMM)) or C or Channelhannel CChannelhannel W Wavelaveleength ngth (D(DWWDDMM)) or C or Channelhannel (D(DWWDDMM)) or C or Chhannelannel
WWavelavelength Rength Range ange  WWaavelveleength Rngth Range ange RRaange (Cnge (CWWDDMM & & WWaavelveleength Rngth Raange nge WWaavelvelength Rength Range ange
((CCWDWDMM & & WWD WWDMM)) ((CCWDWDMM & & WWD WWDMM)) WWDM) (C(CWWDDMM & & W WWWDDMM)) ((CCWWDDM &M & W WWWDDM)M)
W
DM)
OptOptiiccalal Frequenc Frequency (y (THTH zz) f) foor DWr DWDMDM or W or Waavelvelengtength (nmh (nm) f) foor CWr CWDMDM & & W WWWDDMM

Figure 4 – Illustration of adjacent channel isolation
3.3.5
bidirectional (near-end) crosstalk attenuation
in a bidirectional WDM multiplexer (MUX)/demultiplexer (DMUX) device, the bidirectional
(near-end) crosstalk attenuation is defined to be:
BCA = a
mox
where
a is an element of the logarithmic transfer matrix;
mox
m is the MUX input port number;
o is the DMUX output port number;
x is the wavelength number associated with port m.

3.3.6
bidirectional (near-end) isolation
because bidirectional WDM-MUX/DMUX devices have both input channels and output channels
at the same side of the device, input light for one direction can appear on the output port for
the other direction
In the example given below of a four-wavelength bidirectional system, wavelengths 1 and 2
travel from left to right and wavelengths 3 and 4 from right to left (see Figure 5).

– 12 – PAS 62074-1 © IEC:2007(E)

t P , t P , t P , t P
121 1 122 2 423 3 524 4
t P , t P , t P , t P
131 1 132 2 433 3 534 4
P , P
1 2
P
P
Figure 5 – Illustration of a four-wavelength bidirectional system
The bidirectional (near-end) isolation is therefore defined to be:
I = a – a
B mox doc
where
a is an element of the logarithmic transfer matrix;
mox
a is an element of the logarithmic transfer matrix;
doc
d is the DMUX input port number;
o is the DMUX output port number;
c is the (channel) wavelength number associated with port o;
m is the MUX input port number;
x is the wavelength number associated with port m.
For the example given above, the bidirectional isolation of port 2 to wavelength 3 is a – a .

423 121
3.3.7
centre wavelength deviation
differences between the centre wavelength and nominal wavelength (frequency) of the
specified channel for DWDM devices. Where centre wavelength is defined as the centre of the
wavelength range which is x dB less than the peak of insertion loss for the specified channel.
Where 0,5, 1 or 3 are generally used for x.

3.3.8
channel extinction
within the operating wavelength range, difference (in dB) between the minimum powers of the
conducting channels (in dBm) and maximum power of the isolated channels (in dBm)
3.3.9
channel frequency range
frequency range within which a DWDM device is required to operate with a specified
performance. For a particular nominal channel frequency, f , this frequency range is from
nomi
f = (f - Δf ) to f = (f + Δf ), where Δf is the maximum channel centre
imin nomi max imax nomi max max
frequency deviation. Nominal; channel centre frequency and maximum channel centre
frequency deviation are defined in ITU-T Recommendation G.692.

PAS 62074-1 © IEC:2007(E) – 13 –

3.3.10
channel insertion loss
term used for WDM WDM devices which has the same meaning as insertion loss

3.3.11
channel insertion loss deviation

maximum variation of insertion loss over operating wavelength range (channel frequency range

for a DWDM device or channel wavelength range for a coarse WDM (CWDM) and a wide WDM

(WWDM) device) as illustrated in Figure 6 below.

NOTE Channel insertion loss deviation should not to be confused with ripple defined below.

CChannelhannel
CCentralentral
FFrrequencyequency
or Wor Waavelvelengthength
ChannelChannel
ininsseerrttioionn lo lossss
varivariatatiioonn
Insertion loss (dB)
LosLosss m measeasured ured
CChannelhannelFF rrequency equency
over alover alll operat operatiing ng
RRaange (Dnge (DWWDDMM)) or or
ttememperatperaturesures and and
CChhannelannel W Wavelavelength ength
RRange (Cange (CWWDDMM & &
over deviover devicce e
WWDWWDMM))
lifelifettimimee
Optical frequency (THz) for DWDM or wavelength (nm) for CWDM and WWDM

Figure 6 – Illustration of channel insertion loss variation
3.3.12
channel non-uniformity
for a specified set of input ports, difference between maximum and minimum insertion loss at
the output
3.3.13
channel wavelength range
wavelength range within which a CWDM or WWDM device is required to operate a specified
performance. For a particular nominal channel centre wavelength, λ , this wavelength range
nomi
from λ = (λ - Δλ ) to λ = (λ + Δλ ), where Δλ is the maximum channel
imin nomi max imax nomi max max
wavelength deviation.
3.3.14
chromatic dispersion
group delay between two closely spaced wavelengths (or frequencies) inside an optical signal
going through a pair of conducting ports of a WDM device
NOTE It corresponds to the difference between the arrival times of these two closely spaced wavelengths (or
frequencies). Chromatic dispersion is defined as the variation (first order derivative) of this group delay over a
range of wavelengths (or frequencies) especially over the channel operating wavelength (or frequency) range at a
given time, temperature, pressure and humidity. It is expressed as D in terms of units of ps/nm or ps/GHz and it is a
predictor of the broadening of a pulse transmitted through the device.

– 14 – PAS 62074-1 © IEC:2007(E)

2 2
The slope of chromatic dispersion S (with units of ps/nm or ps/GHz ) corresponds to the variation (first order

derivative) of D as a function of wavelength (or frequency) (or second order derivative of the group delay) over the

operating wavelength (or frequency) range, channel per channel. It is particularly critical in the context of large
channel counts (DWDM) or over a wide wavelength range (CWDM or WWDM).

3.3.15
directivity
value of a between two isolated ports which are isolated at every wavelength (or frequency for
ij
a DWDM device). For the example of 6 ports WDM devices shown in Figure 2, the directivity is

a and a between two input ports, and a , a , etc. between two output ports.
12 21 34 43
3.3.16
free spectral range
FSR
difference between two adjacent operating wavelengths for a given input output path (refer to
Figure 7 below)
a
ij
Insertion
loss (dB)
Free spectral
range
Wavelength
Figure 7 – Illustration of free spectral range
3.3.17
insertion loss
value of a (where i ≠ j) at the operating wavelength between two conducting ports. It is the

ij
reduction in optical power between an input and output port of a passive component expressed
in decibels, defined as:
⎛ P ⎞
out
IL = −10log⎜ ⎟
⎜ ⎟
P
⎝ in ⎠
where
P is the optical power launched into the input port;
in
P is the optical power received from the output port.
out
PAS 62074-1 © IEC:2007(E) – 15 –

a
ij
Insertion
loss (dB)
λ
h
Wavelength
Operating
wavelength
Figure 8 – Illustration of insertion loss
For WWDM devices, it is specified as a maximum value and a minimum value at each
operating wavelength range. For DWDM and CWDM devices, it is specified as a maximum
value and a minimum value within the channel frequency (or wavelength) range as illustrated in
Figure 9 below.
Channel centre frequency or wavelength
MMiininimmuumm i innsertsertiion lon loossss
MaMaxxiimmuum inm insseerrttioionn lo lossss
Insertion
loss (dB)
Channel Frequency Range (DWDM) or
Channel Wavelength Range (CWDM & WWDM
Optical Frequency (THz) for DWDM or Wavelength (nm) for CWDM & WWDM

Figure 9 – Illustration of minimum and maximum insertion loss
3.3.18
isolation wavelength
For a pair of ports i and j (where i ≠ j), that are conducting ports at a wavelength λ , a nominal
h
wavelength λ (where λ ≠ λ ), that is an operating wavelength for a different pair of ports, at
k h k
which i and j are isolated ports (refer to Figure 10 below).
NOTE Isolation frequency is also used for DWDM device.

– 16 – PAS 62074-1 © IEC:2007(E)

a
ij
Insertion
a
im
loss (dB)
λ λ
h k
Wavelength
Operating Isolation
wavelength wavelength
Figure 10 – Illustration of isolation wavelength
3.3.19
isolation wavelength range
For a pair of ports i and j that are conducting ports at wavelength λ , the range of wavelengths
h
from λ to λ centred about an operating wavelength λ that is an operating wavelength

kmin kmax k
for a different pair of ports but at which i and j are isolated ports (refer to Figure 11 below).
NOTE Isolation frequency range is also used for the DWDM device.
a
ij
Insertion
a
ik
loss (dB)
λ
h λ
k
Wavelength
λ
kmin λ
kmax
Isolation wavelength range
Figure 11 – Illustration of isolation wavelength range
3.3.20
minimum adjacent channel isolation
difference between the minimum peak of a in the operating wavelength (or frequency) range
ij
and the maximum value of a in a specified range of wavelengths (or frequencies) from λ to
ij kmin
λ centred about an isolation wavelength (or frequency) λ for any two ports i and j, λ
kmax k kmin
PAS 62074-1 © IEC:2007(E) – 17 –

and λ defining an operating wavelength (or frequency) range for a different pair of ports for
kmax
which λ is an operating wavelength (or frequency). (Refer to Figure 12 below).

k
a
ij
Insertion
a
ik
loss (dB)
Min. adj. chan. isol
λ
λ
h
k
Wavelength
Isolation
Operating
wavelength
wavelength
range
range
Figure 12 – Illustration of maximum adjacent channel isolation
3.3.21
maximum total channel isolation
For any two ports i and j (where i ≠ j) the worst case of the cumulative isolation due to the
maximum spectral contributions about all the isolation wavelengths (frequencies) is defined as:
⎡ ⎤
⎢ ⎥
*
⎢ ⎥
t ( λ )
ij h
max
I = −10 ⋅ Log⎢ ⎥
tot
N
⎢ ⎥
*
t ( λ )
⎢ ⎥
ij k
∑
⎢ ⎥
k( k ≠h )
⎣ ⎦
where
N is the number of channels of the device;

λ * is the wavelength (frequency) corresponding to the minimum peak of t in the operating
h ij
wavelength (frequency) range for the pair of ports i and j;
λ * are the wavelengths (frequencies) corresponding to the maximum value of t in the
k ij
specified ranges of wavelengths (frequencies) from λ to λ about the isolation
kmin kmax
wavelengths (frequencies) λ for the pair of ports i and j, λ and λ defining the
k kmin kmax
operating wavelength (frequency) range for the pair of ports for which λ is an operating
k
wavelength (frequency).
3.3.22
non-adjacent channel isolation
unidirectional (far-end) isolation with the restriction that the isolation wavelength (frequency) is
restricted to each of the channels not immediately adjacent to the channel associated with
port o (refer to Figure 13 below).

– 18 – PAS 62074-1 © IEC:2007(E)

NoNonn-- adjadj acent acent  AdAdjjaacceenntt CChannelhannel AdAdjjaacceenntt NoNonn-- adjadj acent acent
CChannelhannel CChannelhannel CeCennttrraall CChannelhannel CChannelhannel

CCentralentral  CeCennttrraall FFrrequencyequency CCentralentral CeCennttrraall
FFrrequencyequency FFrrequencyequency or Wor Wavelaveleengthngth FFrrequencyequency FFrrequencyequency
or Wor Wavelavelengthength or Wor Waavelveleengthngth or Wor Waavelveleengthngth or Wor Wavelavelengthength

adjadjacacentent c channelhannel
aa
ioiocc
Isolation
Isolation
aa
ioioxx
Insertion
-
-
Non
Non
loss (dB)
NoNonn-- adjadj acent Cacent Channelhannel  AAdjdj acentacentCC hannelhannel CChannelhannelFF rrequency equency AAdjdjacentacentCChannelhannel NoNonn-- adjadj aacent Ccent Chhannelannel
FFrrequency Requency Raange nge  FFrrequency Requency Range ange RRange (Dange (DWWDDMM)) or or FFrrequency Requency Range ange FFrrequency Requency Raange nge
(D(DWWDDMM)) or C or Chhannelannel  (D(DWWDDMM)) or C or Chhannelannel CChannelhannel W Wavelaveleength ngth (D(DWWDDMM)) or C or Chhannelannel (D(DWWDDMM)) or C or Chhannelannel
WWavelavelength Rength Range ange  WWavelaveleength Rngth Range ange RRaange (Cnge (CWWDDMM & & WWaavelveleength Rngth Raange nge WWaavelvelength Rength Range ange
((CCWDWDMM & & WWD WWDMM)) (C(CWWDDMM & & W WWWDDMM)) WWDWWDMM)) (C(CWWDDMM & & W WWWDDMM)) ((CCWDWDMM & & WWD WWDMM))
OptOptiiccalal Frequenc Frequency (y (THTH zz)) fo forr D DWWDDMM o orr W Waavveelelennggthth ( (nnmm)) fo forr C CWWDDMM & W & WWWDDMM

Figure 13 – Illustration of non-adjacent channel isolation
3.3.23
operating wavelength
nominal wavelength λ , at which a wavelength-selective branching device operates with the
h
specified performance (refer to Figure 14 below).
NOTE Operating frequency is also used for DWDM device.

a
ij
Insertion
a
ik
loss (dB)
Wavelength
λ
h
Operating wavelength
Figure 14 – Illustration of operating wavelength
3.3.24
operating wavelength range
passband, channel passband
specified range of wavelengths from λ to λ centred about an operating wavelength λ ,
hmin hmax h
within which a wavelength-selective branching device operates with the specified performance
(refer to Figure 15 below)
PAS 62074-1 © IEC:2007(E) – 19 –

NOTE 1 Term “passband” or “channel passband” is used as same meaning of operating wavelength range for

DWDM devices.
NOTE 2 Channel frequency range is also used for DWDM device. It is the frequency range within which a DWDM

device is required to operate with a specified performance. For a particular nominal channel centre frequency, f ,
nomi
this frequency range is from f = (f – Δf ) to f = (f + Δf ), where Δf is the maximum
imin nomi max imax nomi max max

channel centre frequency deviation. Nominal channel centre frequency and maximum channel centre frequency

deviation are system parameters defined for instance in ITU-T Recommendation G.692.

NOTE 3 Channel wavelength range is also used for CWDM. It is the wavelength range within which a CWDM device

is required to operate with a specified performance. For a particular nominal channel centre wavelength, λ , this
nomi
wavelength range is from λ = (λ – Δλ ) to λ = (λ + Δλ ), where Δλ is the maximum
imin nomi max imax nomi max max

channel wavelength deviation.
Operating wavelength range
a
ij
a
ik
Insertion
loss (dB)
λ
h
λ λ
hmin hmax
Wavelength
Figure 15 – Illustration of operating wavelength range
3.3.25
out-of-band attenuation
minimum attenuation (in dB) of channels that fall outside of the operating wavelength range
3.3.26
polarization dependent centre wavelength (PDCW)
maximum variation of channel centre wavelength due to a variation of the state of polarization
(SOP) over all SOPs (refer to Figure 16 below).

a
ij
Insertion
Minimum Maximum
Loss (dB)
centre centre
wavelength wavelength
Polarization dependent centre wavelength
λ
Wavelength
h
Figure 16 – Illustration of polarization dependent centre wavelength (PDCW)

– 20 – PAS 62074-1 © IEC:2007(E)

3.3.27
polarization dependent isolation

PDI
maximum variation of isolation over all the states of polarization

3.3.28
polarization dependent loss
PDL
maximum variation of insertion loss due to a variation of the state of polarization (SOP) over all

the SOPs
3.3.29
polarization dependent reflectance
maximum variation of reflectance due to a variation of the state of polarization (SOP) over all
SOPs
NOTE For DWDM device polarization, dependent centre frequency may also be used.
3.3.30
polarization mode dispersion
PMD
when an optical signal passes through an optical fibre, component or subsystem, such as going
through a pair of conducting ports of a WDM device, the change in the shape and r.m.s. width
of the pulse due to the average delay of the travelling time between the two principal states of
polarization (PSP), differential group delay (DGD), and/or to the waveform distortion for each
PSP, is called PMD
NOTE 1 PMD, together with polarization dependent loss (PDL) and polarization dependent gain (PDG), when
applicable, may introduce waveform distortion leading to unacceptable bit error rate increase.
NOTE 2 PMD may depend on environmental conditions.
3.3.31
principal states of polarization
PSP
at a given optical frequency (or wavelength), the two input (and orthogonal) states of
polarization (SOP) for which the corresponding output SOP are independent of optical
frequency to first order
NOTE 1 In the absence of PDL, the PSPs are orthogonal SOPs with the fast axis PSP having the shortest arrival
time and the slow axis PSP having the longest, the DGD being the difference between these two arrival times.
NOTE 2 An optical fibre, component or
...