1、 International Telecommunication Union ITU-T G.973.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2011) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical fibre submarine cable systems Multichannel DWDM applications with sing
2、le channel optical interfaces for repeaterless optical fibre submarine cable systems Recommendation ITU-T G.973.2 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO
3、ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.
4、449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 General G.900G.909 Parameters for optical fibre ca
5、ble systems G.910G.919 Digital sections at hierarchical bit rates based on a bit rate of 2048 kbit/s G.920G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930G.939 Digital line systems provided by FDM transmission bearers G.940G.949 Digital line systems G.950G.959 Dig
6、ital section and digital transmission systems for customer access to ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979Optical line systems for local and access networks G.980G.989 Access networks G.990G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS
7、 G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.973.2 (04/2011) i Recommendation
8、 ITU-T G.973.2 Multichannel DWDM applications with single channel optical interfaces for repeaterless optical fibre submarine cable systems Summary Recommendation ITU-T G.973.2 provides optical interface specifications towards the realization of transversely compatible dense wavelength division mult
9、iplexing (DWDM) systems intended for repeaterless submarine applications. This Recommendation defines parameters for the single-channel optical interface of physical point-to-point DWDM applications on single-mode optical fibres through the use of the “black-link“ approach. Applications containing D
10、WDM optical amplifiers are not defined in this Recommendation. This Recommendation describes DWDM systems that include the following features: Channel frequency spacing: 100 GHz and below (defined in ITU-T G.694.1). Bit-rate of signal channel: up to 10 Gbit/s. History Edition Recommendation Approval
11、 Study Group 1.0 ITU-T G.973.2 2011-04-13 15 ii Rec. ITU-T G.973.2 (04/2011) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardizat
12、ion Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which mee
13、ts every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts
14、purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is
15、voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ a
16、nd the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may in
17、volve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Re
18、commendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database
19、 at http:/www.itu.int/ITU-T/ipr/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.973.2 (04/2011) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined els
20、ewhere 2 4 Abbreviations 2 5 Convention 3 6 Applications 3 7 Reference configuration 4 7.1 Unidirectional applications . 4 7.2 Bidirectional applications . 4 8 Transverse compatibility 5 9 Parameter definitions 5 9.1 General information 6 9.2 Interface at point SS . 7 9.3 Optical path parameters (si
21、ngle span) from SSto RS . 7 9.4 Interface at point RS . 8 10 Reliability of submarine system . 8 11 Characteristics and performance of submarines cables 9 12 Optical safety considerations 9 Bibliography. 10 Rec. ITU-T G.973.2 (04/2011) 1 Recommendation ITU-T G.973.2 Multichannel DWDM applications wi
22、th single channel optical interfaces for repeaterless optical fibre submarine cable systems 1 Scope The purpose of this Recommendation is to provide optical interface specifications towards the realization of transversely compatible dense wavelength division multiplexing (DWDM) systems intended for
23、repeaterless submarine applications. This Recommendation defines parameters for single-channel optical interface of physical point-to-point DWDM applications on single-mode optical fibres through the use of the “black-link“ approach. Applications containing DWDM optical amplifiers are not defined in
24、 this Recommendation. This Recommendation describes DWDM systems that include the following features: Channel frequency spacing: 100 GHz and below (defined in ITU-T G.694.1). Bit-rate of signal channel: up to 10 Gbit/s. 2 References The following ITU-T Recommendations and other references contain pr
25、ovisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the poss
26、ibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recomm
27、endation. ITU-T G.652 Recommendation ITU-T G.652 (2009), Characteristics of a single-mode optical fibre cable. ITU-T G.653 Recommendation ITU-T G.653 (2010), Characteristics of a dispersion-shifted single-mode optical fibre cable. ITU-T G.654 Recommendation ITU-T G.654 (2010), Characteristics of a c
28、ut-off shifted single-mode optical fibre and cable. ITU-T G.655 Recommendation ITU-T G.655 (2009), Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable. ITU-T G.656 Recommendation ITU-T G.656 (2010), Characteristics of a fibre and cable with non-zero dispersion for wi
29、deband optical transport. ITU-T G.661 Recommendation ITU-T G.661 (2007), Definition and test methods for the relevant generic parameters of optical amplifier devices and subsystems. ITU-T G.671 Recommendation ITU-T G.671 (2009), Transmission characteristics of optical components and subsystems. ITU-
30、T G.691 Recommendation ITU-T G.691 (2006), Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers. ITU-T G.692 Recommendation ITU-T G.692 (1998), Optical interfaces for multichannel systems with optical amplifiers. 2 Rec. ITU-T G.973.2 (04/2011) ITU-T G.694.1 Reco
31、mmendation ITU-T G.694.1 (2002), Spectral grids for WDM applications: DWDM frequency grid. ITU-T G.694.2 Recommendation ITU-T G.694.2 (2003), Spectral grids for WDM applications: CWDM wavelength grid. ITU-T G.698.1 Recommendation ITU-T G.698.1 (2009), Multichannel DWDM applications with single-chann
32、el optical interfaces. ITU-T G.957 Recommendation ITU-T G.957 (2006), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. ITU-T G.959.1 Recommendation ITU-T G.959.1 (2009), Optical transport network physical layer interfaces. ITU-T G.972 Recommendation ITU-T
33、G.972 (2008), Definition of terms relevant to optical fibre submarine cable systems. ITU-T G.973 Recommendation ITU-T G.973 (2010), Characteristics of repeaterless optical fibre submarine cable systems. ITU-T G.978 Recommendation ITU-T G.978 (2010), Characteristics of optical fibre submarine cables.
34、 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 dense wavelength division multiplexing (DWDM): ITU-T G.972. 3.1.2 multichannel receive main path interface reference point (MPI-RM): ITU-T G.959.1. 3.1.3 multichannel source main path int
35、erface reference point (MPI-SM): ITU-T G.959.1. 3.1.4 optical tributary signal: ITU-T G.959.1. 3.1.5 optical tributary signal class NRZ 2.5G: ITU-T G.959.1. 3.1.6 optical tributary signal class NRZ 10G: ITU-T G.959.1. 3.1.7 polarization mode dispersion (PMD): ITU-T G.650.2. 3.1.8 transverse compatib
36、ility: ITU-T G.957. 3.1.9 wavelength division multiplexing (WDM): ITU-T G.972. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ASE Amplified Spontaneous Emission BER Bit Error Ratio CSF Cut-off Shifted single-mode Fibre CWDM Coarse Wavelength Division
37、Multiplexing DCF Dispersion Compensating single-mode Fibre DGD Differential Group Delay DSF Dispersion Shifted single-mode Fibre Rec. ITU-T G.973.2 (04/2011) 3 DWDM Dense Wavelength Division Multiplexing EX EXtinction ratio FEC Forward Error Correction IrDI Inter-Domain Interface LEF Large Effective
38、 area single-mode Fibre MPI Main Path Interface NDF Negative Dispersion single-mode Fibre NE Network Element NRZ Non-Return to Zero NZDSF Non-Zero Dispersion Shifted single-mode Fibre OA Optical Amplifier OD Optical Demultiplexer OM Optical Multiplexer OTN Optical Transport Network PMD Polarization
39、Mode Dispersion RSSingle-channel reference point at the DWDM network element tributary output RZ Return to Zero SDH Synchronous Digital Hierarchy SSSingle-channel reference point at the DWDM network element tributary input WDM Wavelength Division Multiplexing WNZDF Wideband Non-Zero Dispersion singl
40、e-mode Fibre 5 Convention This clause is intentionally left blank. 6 Applications This Recommendation provides the physical layer parameters for the single-channel interfaces of dense wavelength division multiplexing (DWDM) multi-channels optical repeaterless submarine systems. These DWDM systems wi
41、th single-channel interfaces are intended to be used in point to point applications. The specification method in this Recommendation uses a “black-link“ approach, which means that optical interface parameters for only (single-channel) optical tributary signals are specified. This approach enables tr
42、ansverse compatibility at the single-channel point using a direct wavelength-multiplexing configuration. However, it does not enable transverse compatibility at the multichannel points. In this approach, the optical multiplexer (OM) and optical demultiplexer (OD) are treated as a single set of optic
43、al devices. This Recommendation only considers DWDM applications where the black-link does not contain optical amplifiers. 4 Rec. ITU-T G.973.2 (04/2011) 7 Reference configuration 7.1 Unidirectional applications Figure 7-1 shows a set of reference points, for the “black-link“ approach, for single-ch
44、annel connection (SSand RS) between transmitters (Tx) and receivers (Rx). Here the DWDM link includes an OM and an OD, which are used as a pair with the opposing element. The fibre between point SSor RSand the DWDM link is considered to be part of the black-link in cases where the transmitter or rec
45、eiver is some distance far from the OM or OD. Tx 1Tx 2SSTx NSSSSRSRSRSRx 1Rx 2Rx NODDWDM linkPair of DWDM network elementsOMMPI-S MPI-RFigure 7-1 “black-link“ approach for unidirectional applications This reference model does not include any optical amplifiers in the DWDM system. The reference point
46、s in Figure 7-1 are defined as follows: SSis a single-channel reference point at the DWDM link tributary input; RSis a single-channel reference point at the DWDM link tributary output; MPI-S is a link reference point at the DWDM network element aggregate output; MPI-R is a link reference point at th
47、e DWDM network element aggregate input. Note that MPI-S and MPI-R are only defined to provide information for the fibre link and not to provide signal characteristics at these points. 7.2 Bidirectional applications Figure 7-2 shows a set of reference points, for the single-fibre bidirectional “black
48、-link“ approach, for single-channel connection (SSand RS) between transmitters (Tx) and receivers (Rx). Here the DWDM network elements include an OM/OD, which is used as a pair with the opposing element. Tx 1Tx 2SSRx N1Rx NSSRSRSRSRSSSSSRx 1Rx 2Tx N1Tx NOD/OMDWDM linkPair of DWDM network elementsOM/
49、ODMPI-S forsignalsgoing MPI-R forsignalsgoing MPI-S forsignalsgoing MPI-R forsignalsgoing Figure 7-2 “black-link“ approach for bidirectional applications The reference points in Figure 7-2 are as defined in clause 7.1. Rec. ITU-T G.973.2 (04/2011) 5 8 Transverse compatibility b-ITU-T G.Sup41 describes several transverse compatibility configurations for point to point submarine transmission systems. This Recommendation deals with a single-span black-link t
