IEC 60728-13-1:2017

IEC 60728-13-1 ®
Edition 2.0 2017-07
INTERNATIONAL
STANDARD
colour
inside
Cable networks for television signals, sound signals and interactive services –
Part 13-1: Bandwidth expansion for broadcast signal over FTTH system

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IEC 60728-13-1 ®
Edition 2.0 2017-07
INTERNATIONAL
STANDARD
colour
inside
Cable networks for television signals, sound signals and interactive services –

Part 13-1: Bandwidth expansion for broadcast signal over FTTH system

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.01; 33.180.01 ISBN 978-2-8322-4578-1

– 2 – IEC 60728-13-1:2017 © IEC 2017
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, symbols and abbreviated terms . 8
3.1 Terms and definitions. 8
3.2 Symbols . 15
3.3 Abbreviated terms . 16
4 Overview . 18
5 Optical system reference model . 18
6 Preparation of measurement . 20
6.1 Environmental conditions . 20
6.1.1 Standard measurement conditions . 20
6.1.2 Standard operating condition . 20
6.1.3 Standard signal and measuring equipment . 20
6.2 Accuracy of measuring equipment . 21
6.3 Source power . 21
7 Methods of measurement . 21
7.1 Measuring points . 21
7.2 Measuring parameters . 22
7.3 Optical power . 23
7.4 Optical wavelength . 23
7.5 Signal level and signal-to-noise ratio. 23
7.5.1 General . 23
7.5.2 Measurement setup . 23
7.5.3 Measurement conditions . 24
7.5.4 Measurement method for xPSK signals . 24
7.5.5 Presentation of the results . 24
7.6 RIN and signal-to-noise ratio . 24
7.6.1 General . 24
7.6.2 Measuring points and measurement setup . 25
7.6.3 Measurement conditions . 25
7.6.4 System RIN measurement method . 26
7.6.5 S/N calculation based on RIN value . 27
7.6.6 Calculation of component RIN . 28
7.7 Optical modulation index . 29
7.8 Signal-to-crosstalk ratio (SCR) . 29
8 Specification of optical system for broadcast signal transmission . 29
8.1 Digital broadcast system over optical network . 29
8.2 International TV systems. 29
8.3 Relationship between RIN and S/N . 30
8.4 Optical wavelength . 32
8.5 Frequency of source signal . 33
8.6 Optical system specification for satellite signal transmission . 33
8.7 S/N ratio specification for in-house and in-building wirings . 34
8.8 Crosstalk due to optical fibre non-linearity . 35

8.9 Single frequency interference level due to fibre non-linearity . 35
8.10 Environment condition . 35
Annex A (informative) Actual service systems and design considerations . 36
A.1 General . 36
A.2 Metropolitan type CATV . 36
A.3 Municipal type CATV. 37
A.4 Poor signal reception type CATV . 38
A.5 System reference model . 38
A.5.1 System parameters . 38
A.5.2 Operating environment . 39
A.6 Guidelines for actual operation . 47
A.6.1 Optical transmitter . 47
A.6.2 Optical amplifier . 47
Annex B (informative) Wavelength division multiplexing . 48
B.1 Optical wavelength grid (optical frequency grid) . 48
B.2 Nominal central frequencies and wavelengths . 48
B.3 Notes regarding wavelength division multiplexing . 50
B.3.1 Crosstalk between two wavelengths . 50
B.3.2 Receiving two wavelengths by single V-ONU . 52
Annex C (informative) Minimum wavelength separation . 54
C.1 Optical beat interference . 54
C.2 Range of wavelength variation . 55
C.3 WDM system using optical filters and couplers . 56
Annex D (informative) Relation between S/N degradation and rain attenuation . 59
Bibliography . 61

Figure 1 – FTTH Cable TV system using one-wavelength . 19
Figure 2 – FTTH Cable TV system using two wavelengths . 19
Figure 3 – Performance specified points of the optical system . 19
Figure 4 – Measuring points in a typical video distribution system . 22
Figure 5 – Measurement of optical wavelength . 23
Figure 6 – Measurement of signal level and signal-to-noise ratio . 24
Figure 7 – Measuring points in a typical FTTH system . 25
Figure 8 – RIN measurement setup . 25
Figure 9 – Performance allocation and measuring points . 29
Figure 10 – Section of S/N ratio specification (38 dB) for in-house wiring . 34
Figure 11 – Section of S/N ratio specification (24 dB) for in-building wiring (in case of
coaxial cable distribution after V-ONU) . 35
Figure A.1 – Example of a multi-channel service system of one million terminals . 37
Figure A.2 – Example of a multi-channel service system with 2 000 terminals . 37
Figure A.3 – Example of a multi-channel with CS supplementary service system for 2 000
terminals . 37
Figure A.4 – Example of a re-transmission service system with 72 terminals . 38
Figure A.5 – Example of a re-transmission service system with 144 terminals . 38
Figure A.6 – System performance calculation for model A . 41
Figure A.7 – System performance calculation for model B . 42

– 4 – IEC 60728-13-1:2017 © IEC 2017
Figure A.8 – System performance calculation for model C . 43
Figure A.9 – System performance calculation for model D . 44
Figure A.10 – System performance calculation for model E . 45
Figure A.11 – System performance calculation for model F . 46
Figure B.1 – Linear crosstalk between two wavelengths . 51
Figure B.2 – Wavelength dependency of Raman crosstalk . 51
Figure B.3 – Nonlinear crosstalk between two wavelengths . 52
Figure B.4 – Frequency dependency of cross-phase modulation . 52
Figure B.5 – S/N degradation (two wavelengths into one V-ONU case) . 53
Figure C.1 – Experimental results of RIN degradation due to optical beat . 55
Figure C.2 – Wavelength variation of a DWDM transmitter against ambient temperature . 56
Figure C.3 – Wavelength variation of a CWDM transmitter against ambient temperature . 56
Figure C.4 – Example of wavelength division multiplexing using WDM filter . 57
Figure C.5 – Example of CWDM filter design . 57
Figure C.6 – Example of wavelength division multiplexing using optical coupler . 58

Table 1 – Level of RF signals . 13
Table 2 – Measuring instruments . 21
Table 3 – Measuring points and measured parameters . 22
Table 4 – Parameters used to calculate S/N when signals of multiple wavelengths are
received by a single V-ONU . 28
Table 5 – Minimum RF signal-to-noise ratio requirements in operation . 30
Table 6 – Types of broadcast services . 31
Table 7 – Type of service and minimum operational RIN values for satellite services . 32
Table 8 – performance of optical wavelength and power . 33
Table 9 – Optical system specification . 33
Table 10 – Section of S/N ratio specification for in-house/in-building wiring . 34
Table 11 – Interference level due to fibre non-linearity (single frequency interference) . 35
Table A.1 – Basic system parameters (Japan) . 39
Table B.1 – Example nominal central frequencies of the DWDM grid . 49
Table B.2 – Nominal central wavelength for spacing of 20 nm (ITU-T G.694.2) . 50

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CABLE NETWORKS FOR TELEVISION SIGNALS,
SOUND SIGNALS AND INTERACTIVE SERVICES –

Part 13-1: Bandwidth expansion for broadcast signal over FTTH system

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 60728-13-1 has been prepared by technical area 5: Cable networks
for television signals, sound signals and interactive services, of IEC technical committee 100:
Audio, video and multimedia systems and equipment.
This second edition cancels and replaces the first edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition.
• Transmission frequency was expanded in order to achieve satellite signal for 4 K video
service. The transmission frequency over FTTH would be 3 300 MHz.
• High signal modulation case like 16 APSK and 32 APSK was added in order to correspond to
transmission for 4 K video service.

– 6 – IEC 60728-13-1:2017 © IEC 2017
The text of this International Standard is based on the following documents:
FDIS Report on voting
100/2927/FDIS 100/2959/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60728 series, published under the general title Cable networks for
television signals, sound signals and interactive services, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
The contents of the corrigendum of September 2017 have been included in this copy.

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.
INTRODUCTION
Standards and deliverables of the IEC 60728 series deal with cable networks including
equipment and associated methods of measurement for headend reception, processing and
distribution of television and sound signals and for processing, interfacing and transmitting all
kinds of data signals for interactive services using all applicable transmission media. These
signals are typically transmitted in networks by frequency-multiplexing techniques.
This includes for instance
• regional and local broadband cable networks,
• extended satellite and terrestrial television distribution systems,
• individual satellite and terrestrial television receiving systems,
and all kinds of equipment, systems and installations used in such cable networks, distribution
and receiving systems.
The extent of this standardization work is from the antennas and/or special interfaces to the
headend or other interface points to the network up to any terminal interface of the customer
premises equipment.
The standardization work will consider coexistence with users of the RF spectrum in wired and
wireless transmission systems.
The standardization of any user terminals (i.e. tuners, receivers, decoders, multimedia terminals,
etc.) as well as of any coaxial, balanced and optical cables and accessories thereof is excluded.

– 8 – IEC 60728-13-1:2017 © IEC 2017
CABLE NETWORKS FOR TELEVISION SIGNALS,
SOUND SIGNALS AND INTERACTIVE SERVICES –

Part 13-1: Bandwidth expansion for broadcast signal over FTTH system

1 Scope
The purpose of this part of IEC 60728 is the precise description of an FTTH (fibre to the home)
system for expanding broadband broadcast signal transmission from CATV services only,
towards CATV plus broadcast satellite (BS) plus communication satellite (CS) services,
additionally to other various signals such as data services.
The scope is limited to the RF signal transmission over FTTH systems.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60728-1:2014, Cable networks for television signals, sound signals and interactive
services – Part 1: System performance of forward paths
IEC 60728-6:2011, Cable networks for television signals, sound signals and interactive
services – Part 6: Optical equipment
IEC 60728-13:2010, Cable networks for television signals, sound signals and interactive
services – Part 13: Optical systems for broadcast signal transmissions
IEC 60728-113:—, Cable networks for television signals, sound signals and interactive services
– Part 113: Optical systems for broadcast signal transmissions loaded with digital channels
only
IEC 61280-1-3:2010, Fibre optic communication subsystem test procedures – Part 1-3:
General communication subsystems – Central wavelength and spectral width measurement
ITU-T Recommendation G.694.1, Spectral grids for WDM applications: DWDM frequency grid
ITU-T Recommendation G.694.2, Spectral grids for WDM applications: CWDM wavelength
grid
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
___________
Under preparation. Stage at the time of publication: IEC ACDV 60728-113: 2017.

ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
regional broadband cable network
network designed to provide sound and television signals as well as signals for interactive
services to a regional area covering several towns and/or villages
3.1.2
local broadband cable network
network designed to provide sound and television signals as well as signals for interactive
services to a local area (e.g. one town or one village)
3.1.3
extended satellite television distribution network or system
distribution network or system designed to provide sound and television signals received by
satellite receiving antenna to households in one or more buildings
Note 1 to entry: This kind of network or system can be combined with terrestrial antennas for the additional reception
of TV and/or radio signals via terrestrial networks.
Note 2 to entry: This kind of network or system can also carry control signals for satellite switched systems or other
signals for special transmission systems (e.g. MoCA or WiFi) in the return path direction.
3.1.4
extended terrestrial television distribution network or system
distribution network or system designed to provide sound and television signals received by
terrestrial receiving antennas to households in one or more buildings
Note 1 to entry: This kind of network or system can be combined with a satellite antenna for the additional reception
of TV and/or radio signals via satellite networks.
Note 2 to entry: This kind of network or system can also carry other signals for special transmission systems (e.g.
MoCA or WiFi) in the return path direction.
3.1.5
individual satellite television receiving system
system designed to provide sound and television signals received from satellite(s) to an
individual household
Note 1 to entry: This kind of system can also carry control signals for satellite switched systems or other signals for
special transmission systems (e.g. MoCA or WiFi) in the return path direction.
3.1.6
individual terrestrial television receiving system
system designed to provide sound and television signals received via terrestrial broadcast
networks to an individual household
Note 1 to entry: This kind of system can also carry other signals for special transmission systems (e.g. MoCA or WiFi)
in the return path direction.
3.1.7
optical transmitting unit
optical transmitter
transmit fibre optic terminal device accepting at its input port an electrical signal and providing at
its output port an optical carrier modulated by that input signal
Note 1 to entry: For the purposes of this document, optical transmitters may have more than one input port accepting
electrical RF signals.
– 10 – IEC 60728-13-1:2017 © IEC 2017
Note 2 to entry: This piece of equipment amplifies frequency multiplexed electrical signals and converts these
electrical signals into optical signals. The optical wavelength is a 1 500 nm band (1 550 nm ± 10 nm in 1 530 nm to
1 625 nm region).
Note 3 to entry: The wavelength and necessary wavelength separation are described in Annexes B and C,
respectively.
[SOURCE: IEC 60728-13:2010, 3.1.1, modified — Note 3 has been added.]
3.1.8
optical receiving unit
optical receiver
receive fibre optic terminal device accepting at its input port a modulated optical carrier, and
providing at its output port the corresponding demodulated electrical signal (with the associated
clock, if digital)
Note 1 to entry: For the purposes of this document, optical receivers may have more than one output port providing
electrical RF signals.
[SOURCE: IEC TR 61931:1998, 2.9.7, modified — Note 1 has been added.]
3.1.9
optical amplifier
optical waveguide device containing a suitably pumped, active medium which is able to amplify
an optical signal
Note 1 to entry: In this document, erbium doped fibre amplifier (EDFA) is used for amplification in the 1 550 nm
band.
Note 2 to entry: There are several methods based on the wavelength to be used for amplification. The term “erbium
doped fibre amplifier (EDFA)” is the synonym of optical amplifier in this document.
[SOURCE: IEC TR 61931, 2.7.75, modified — Notes 1 and 2 have been added.]
3.1.10
fibre optic branching device
optical fibre coupler
splitter
optical fibre device, possessing three or more optical ports, which shares optical power among
its ports in a predetermined fashion, at the same wavelength or wavelengths, without
wavelength conversion
Note 1 to entry: The ports may be connected to fibres, detectors, etc.
[SOURCE: IEC TR 61931:1998, 2.6.21, modified — The term "splitter" has been added, "optical
fibre branching" device has been deleted and "optical fibre coupler" is a preferred rather than a
deprecated term.]
3.1.11
multiplexing device
WDM device
wavelength selective branching device (used in WDM transmission systems) in which optical
signals can be transferred between two predetermined ports, depending on the wavelength of
the signal
[SOURCE: IEC TR 61931:1998, 2.6.51]
3.1.12
optical modulation index
th
optical modulation index of k RF signal, OMI , which is defined as
k
φ − φ
h l
OMI =
k
φ + φ
h l
where
φ is the highest, and
h
φ is the lowest instantaneous optical power of the intensity modulated optical signal, and
l
k is the considered RF signal
Note 1 to entry: This definition does not apply to systems where the input signals are converted and transported as
digital baseband signals. In this case, the terms modulation depth or extinction ratio defined in 2.6.79 and 2.7.46 of
IEC TR 61931:1998 are used. A test procedure for extinction ratio is described in IEC 61280-2-2.
[SOURCE: IEC 60728-6:2011, 3.1.10, modified — The definition has been clarified and Notes 1
and 2 have been replaced by a new Note 1.]
3.1.13
total optical modulation index
, which is
resulting optical modulation index when more than one RF signal is transmitted, OMI
tot
defined as
K
OMI = OMI
tot ∑ k
k =1
where
OMI is the optical modulation index of the k-th RF signal;
k
K is the total number of RF signals.
3.1.14
relative intensity noise
RIN
ratio of the mean square of the intensity fluctuations in the optical power of a light source to the
square of the mean of the optical output power
-1
Note 1 to entry: RIN is usually expressed in dB (Hz ) resulting in negative values.
Note 2 to entry: The value of RIN can also be calculated from the results of a signal-to-noise measurement for the
system.
[SOURCE: IEC 60728-13:2010, definition 3.1.8]
3.1.15
responsivity
ratio of an optical detector’s electrical output to its optical input at a given wavelength
Note 1 to entry: The responsivity is generally expressed in ampere per watt or volt per watt of incident radiant power.
Note 2 to entry: Sensitivity is sometimes used as an imprecise synonym for responsivity.
Note 3 to entry: The wavelength interval around the given wavelength may be specified.
[SOURCE: IEC 60728-6, 3.1.14]
3.1.16
wavelength
distance covered in a period by the wavefront of a harmonic plane wave
Note 1 to entry: The wavelength of light in vacuum is given by
λ
– 12 – IEC 60728-13-1:2017 © IEC 2017
c
λ =
f
where
c is the speed of light in vacuum (c = 2,997 92 × 10 m/s);
is the optical frequency.
f
Although the wavelength in dielectric material, such as fibres, is shorter than in vacuum, only the wavelength of light
in vacuum is used.
[SOURCE: IEC 60728-13:2010, 3.1.10]
3.1.17
central wavelength
average of those wavelengths at which the amplitude of a light source reaches or last falls to half
of the maximum amplitude
[SOURCE: IEC 60728-6:2011, 3.1.26, modified — The term "centre wavelength" has been
replaced by "central wavelength".]
3.1.18
quadrature amplitude modulation
QAM
amplitude modulation by two separate signals of two sinusoidal carriers having the same
amplitude and frequency but being in phase quadrature, the modulated signals being added for
transmission in a single channel
[SOURCE: IEC 60050-702:1992, 702-06-63]
3.1.19
QAM signal
signal utilizing quadrature amplitude modulation as its modulation method
3.1.20
orthogonal frequency division multiplexing
OFDM
orthogonal frequency division multiplexing is one of the multiplexing schemes used for the
transportation of terrestrial digital broadcasting SDTV and HDTV signals
Note 1 to entry: OFDM is based on the idea of frequency-division multiplexing, where each frequency channel is
modulated with a simpler modulation, and the frequencies and modulation of FDM are arranged to be orthogonal with
each other, which almost eliminates the interference between channels.
[SOURCE: IEC 60728-13:2010, 3.1.14, modified — OFDM has been specified and "OFDM
signal" has been deleted and given as a new entry.]
3.1.21
OFDM signal
signal utilizing orthogonal frequency division multiplexing as the multiplexing scheme
3.1.22
phase shift keying
PSK
angle modulation in which each significant condition in a modulating discretely-timed signal is
represented by a specified phase of a periodic sinusoidal oscillation.
[SOURCE: IEC 60050-721:1991, 721-06-07, modified — The preferred terms "phase shift
modulation" and "phase shift signalling" have been deleted.]

3.1.23
PSK signal
signal utilizing phase shift keying as its modulation method
3.1.24
amplitude phase shift keying
APSK
digital modulation scheme that conveys data by changing, or modulating, both the amplitude and
the phase of a reference signal
Note 1 to entry: APSK combines both amplitude-shift keying (ASK) and phase-shift keying (PSK) to increase the
symbol-set.
3.1.25
APSK signal
signal utilizing amplitude phase shift keying as its modulation scheme
3.1.26
level of digitally modulated signal
RMS power of the signal within the channel bandwidth (S)
Note 1 to entry: The level of digital signal is the average electrical power of the overall signal comprised of each
signal and is not the individual signal level of the multi-carrier signal, as shown in Table 1.
Table 1 – Level of RF signals
Signal Level detection Symbol Remarks
QAM signal
The value is averaged over
OFDM signal
Digitally a sufficiently long period of
a
modulated xPSK signal  RMS value S time compared to the period
signals of the lowest frequency
16 APSK signal
used for the modulation.
32 APSK signal
The carrier level is a
b
FM audio carrier C
RMS value
rms
constant value.
a
xPSK means QPSK,8PSK,TC8PSK, etc.
b
FM radio is not a kind of digitally modulated signals. However, it may exist in some digitally modulated optical
broadcast system.
Note 2 to entry: The level of digitally modulated signal can be expressed in dB(mW) or in dB(μV) referred to 75 Ω.
3.1.27
S/N ratio
signal to noise ratio for a digitally modulated signal in the RF band
Note 1 to entry: In this document only digitally modulated carriers are considered. S/N is used only for a digitally
modulated signal which expresses the same as S /N used in IEC 60728-1:2014, 3.1.80.
D,RF
3.1.28
D/U ratio
ratio of desired signal level, D, to undesired signal level, U
Note 1 to entry: The D/U ratio is generally used for multiple frequency interference as CSO and CTB, for single
frequency interference as SCR.
Note 2 to entry: D/U ratio is expressed in dB.
[SOURCE: IEC 60728-13:2010, definition 3.1.20, modified — CCR in note 1 has been changed
to SCR.]
– 14 – IEC 60728-13-1:2017 © IEC 2017
3.1.29
single or multiple frequency interference ratio
ratio of desired signal level to undesired signal level
Note 1 to entry: The ratio of desired signal level, D (dB(µV)), to undesired signal level, U (dB(µV)) is given by
D/U (dB) = D – U
Note 2 to entry: The desired and the undesired signals can also be expressed both in dB(mW).
Note 3 to entry: Note the similarity of the definition to the definition of S/N ratio.
3.1.30
optical line terminal
OLT
central office-terminal equipment that is linked with the Optical Network Unit (ONU) in the
customer premises
Note 1 to entry: The OLT usually connects with headend equipment.
[SOURCE: IEC 60728-13:2010, 3.1.22]
3.1.31
optical network unit
ONU
device at the customer premises equipment that is linked with the Optical Line Terminal (OLT)
Note 1 to entry: The ONU usually connects with customer premises equipment.
3.1.32
video-optical network unit
V-ONU
terminal unit that changes the optical signal of a broadcast system into an electric signal
Note 1 to entry: The term V-ONU is used as the synonym of optical receiver (O/E) in this document.
[SOURCE: IEC 60728-13:2010, 3.1.24]
3.1.33
stimulated Brillouin scattering
SBS
non-linear scattering of optical radiation characterized by a frequency shift as for the Raman
scattering, but accompanied by a lower frequency (acoustical) vibration of the medium lattice;
the light is scattered backward with respect to the incident radiation
Note 1 to entry: In silica fibres the frequency shift is typically around 10 GHz.
Note 2 to entry: SBS results in loss of optical level and affects the performance of analogue optical system.
Note 3 to entry: The frequency shift is characterized by a frequency downshift (that is to a longer wavelength) due to
a GHz frequency acoustical vibration (frequency downshift is 10 GHz or 11 GHz, and gain bandwidth 20 MHz).
[SOURCE: IEC 60728-13:2010, 3.1.25]
3.1.34
stimulated Raman scattering
SRS
non-linear scattering of optical radiation characterized by a wavelength shift and accompanied
by very high frequency vibration of the medium lattice, strongly enhanced by the presence of
already scattered radiation
Note 1 to entry: In silica fibres the wavelength shift is typically around 100 nm for an exciting radiation with a
wavelength around 1 550 nm.
Note 2 to entry: Stimulated Raman scattering can occur in both forward and backward directions and can cause
crosstalk between optical signals of different wavelengths.
Note 3 to entry: Frequency downshift is about 13 THz and gain bandwidth about 20 GHz.
[SOURCE: IEC 60728-13:2010, 3.1.27]
3.1.35
cross-phase modulation
XPM
modulation caused by the nonlinear refractive index of the fibre material
Note 1 to entry: It has a relationship with the wavelength spacing in optical transmission system. The more spacing
becomes broader, the more XPM value decreases. In such WDM system having 1 490 nm (communication signal) and
1 550 nm (broadcast signal) wavelengths, XPM becomes negligibly small compared with SRS due to this relationship.
Note 2 to entry: XPM affects the performance of the wavelength division multiplex system.
[SOURCE: IEC 60728-13:2010, 3.1.28, modified — The definition has been improved.]
3.1.36
signal to crosstalk ratio
SCR
level difference of CATV broadcast signal level and worst case level of another service’s single
frequency crosstalk signal measured at an RF output port of an optical receiver for CATV
broadcast service
SCR = D – U
CATV OtherService
where
D is the nominal level of a CATV broadcast signal in dB(µV) at an RF output
CATV
port of an optical CATV broadcast receiver
U is the worst case level of another service’s single frequency crosstalk in
OtherService
dB(µV), within the measurement signal bandwidth, at an RF output port of an
optical CATV broadcast receiver. The value of U is mainly due to
OtherService
the Raman scattering effect from other services such as xPON.

Note 1 to entry: SCR is expressed in dB.
3.2 Symbols
The following graphical symbols are used in the figures of this document. These symbols are
either listed in IEC 60617 or based on symbols defined in IEC 60617.

– 16 – IEC 60728-13-1:2017 © IEC 2017
Optical transmitter Optical amplifier
E
based on based on
O [IEC 60617-S00213 [IEC 60617-S01239

(2001-07)] (2001-07)]
Variable attenuator
Optical fibre
[IEC 60617-S01245,
[IEC 60617-S01318
modified
A
(2001-07)]
(2001-07)]
Optical receiver Power meter
O
based on [IEC 60617-S00059,
P
E
[IEC 60617-S00213 IEC 60617-S00910

(2001-07)] (2001-07)]
Electrical spectrum
analyser
P(f)
Amplifier
based on
[IEC 60617-S01239
[IEC 60617-S00059,
(2001-07)]
IEC 60617-S00910
(2001-07)]
Ammeter
Photodiode with fibre
based on
A
pigtail
[IEC 60617-S00059,
[IEC 60617-S01327
IEC 60617-S00910
(2001-07)]
(2001-07)-]
coupler Optical
[IEC 60617-S00059,
Filter
Optical filter
IEC 60617-S01188
(2001-07)]
Optical terminator
NF
[IEC 60617-S01389,
Meter NF meter
IEC 60617-S01318
(2001-07)]
Optical splitter
TV
based on
n
Television set
[IEC TR 61930:1998,
3.33.1]
Video optical network
WDM
WDM filter
V-ONU
unit
3.3 Abbreviated terms
AGC automatic gain control AM amplitude modulation

APSK amplitude phase shift keying APC angled physical contact op
...