1、 International Telecommunication Union ITU-T G.973.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2009) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical fibre submarine cable systems Longitudinally compatible DWDM applicati
2、ons for repeaterless optical fibre submarine cable systems Recommendation ITU-T G.973.1 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 ALL ANALOGUE CARRIER-TRANS
3、MISSION 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.449 COORDINATION OF RADIOT
4、ELEPHONY 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 cable systems G.910G.919 Dig
5、ital 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 Digital section and digital t
6、ransmission 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 G.1000G.1999 TRANSMISSION
7、 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.973.1 (11/2009) i Recommendation ITU-T G.973.1 Longitudina
8、lly compatible DWDM applications for repeaterless optical fibre submarine cable systems Summary Recommendation ITU-T G.973.1 provides physical layer specifications for dense wavelength division multiplexing (DWDM) applications for repeaterless optical fibre submarine cable systems. Longitudinally co
9、mpatible applications for DWDM applications for repeaterless optical fibre submarine cable systems are described for point-to-point, multichannel line systems without remotely pumped optical amplifiers. The primary purpose is to enable multiple vendors to design DWDM transmission equipment for subma
10、rine fibre links that are compliant with this Recommendation. History Edition Recommendation Approval Study Group 1.0 ITU-T G.973.1 2009-11-13 15 ii Rec. ITU-T G.973.1 (11/2009) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecomm
11、unications, information and communication technologies (ICTs). The ITU Telecommunication Standardization 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 telecommun
12、ications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets 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 proced
13、ure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts 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 teleco
14、mmunication administration and a recognized operating agency. Compliance with this Recommendation is 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 thes
15、e mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and 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
16、draws attention to the possibility that the practice or implementation of this Recommendation may involve 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 member
17、s or others outside of the Recommendation development process. As of the date of approval of this Recommendation, 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
18、represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 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.973.1
19、(11/2009) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 3.1 Terms defined elsewhere 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Classification of optical interfaces 3 6.1 Applications 3 6.2 Reference configurations 3 7 Single-span longitudinal compatibility . 4 8 Par
20、ameters. 4 8.1 Maximum attenuation . 4 8.2 Fibre types 4 8.3 Wavelength ranges . 5 8.4 Maximum chromatic dispersion . 5 8.5 Minimum local chromatic dispersion coefficient . 5 8.6 Maximum differential group delay . 6 8.7 Minimum effective area . 7 9 Characteristics and performance of the system 7 9.1
21、 System reliability performance . 7 9.2 System capacity upgrading . 7 10 Characteristics and performance of the submarine cable . 8 11 Optical safety considerations 8 Bibliography. 9 Rec. ITU-T G.973.1 (11/2009) 1 Recommendation ITU-T G.973.1 Longitudinally compatible DWDM applications for repeaterl
22、ess optical fibre submarine cable systems 1 Scope This Recommendation provides physical layer specifications for dense wavelength division multiplexing (DWDM) applications in point-to-point repeaterless optical fibre submarine cable systems. The goal is to enable longitudinally compatible applicatio
23、ns. The primary purpose is to enable multiple vendors to provide transmission equipment for submarine fibre links that are compliant with this Recommendation. This Recommendation includes a generic reference model for the physical layer applications. The specifications take into account parameters s
24、uch as maximum attenuation, fibre types, wavelength ranges, maximum chromatic dispersion, minimum local chromatic dispersion coefficient, maximum differential group delay, and minimum effective area. This Recommendation focuses on repeaterless optical fibre submarine cable systems without remotely p
25、umped optical amplifiers. This Recommendation presumes that the optical tributary signals transported within optical channels are digital. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Rec
26、ommendation. 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 possibility of applying the most recent edition of the Recommendations and other refe
27、rences 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 Recommendation. ITU-T G.650.2 Recommendation ITU-T G.650.2 (2007), Definitions and test
28、 methods for statistical and non-linear related attributes of single-mode fibre and cable. ITU-T G.652 Recommendation ITU-T G.652 (2009), Characteristics of a single-mode optical fibre and cable. ITU-T G.653 Recommendation ITU-T G.653 (2006), Characteristics of a dispersion-shifted single-mode optic
29、al fibre and cable. ITU-T G.654 Recommendation ITU-T G.654 (2006), Characteristics of a cut-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
30、 ITU-T G.656 (2006), Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport. ITU-T G.959.1 Recommendation ITU-T G.959.1 (2009), Optical transport network physical layer interfaces. ITU-T G.978 Recommendation ITU-T G.978 (2006), Characteristics of optical fibre s
31、ubmarine cables. 2 Rec. ITU-T G.973.1 (11/2009) 3 Terms and definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 The following term is defined in ITU-T G.650.2: polarization mode dispersion (PMD) 3.1.2 The following term is defined in b-ITU-T
32、G.696.1: client class 3.1.3 The following term is defined in b-ITU-T G.709: optical transport hierarchy (OTH) 3.1.4 The following term is defined in b-ITU-T G.780: synchronous digital hierarchy (SDH) 3.1.5 The following terms are defined in b-ITU-T G.972: dense wavelength division multiplexing (DWDM
33、) dense wavelength division multiplexing system (DWDMS) wavelength division multiplexing (WDM) 3.1.6 The following terms are defined in ITU-T G.959.1: multichannel receive main path interface reference point (MPI-RM) multichannel source main path interface reference point (MPI-SM) 3.1.7 The followin
34、g term is defined in b-ITU-T G-Sup.40: dispersion compensating single-mode fibre (DCF) 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: Aeff Effective area CSF Cut-off Shifted single-mode Fibre DCF Dispersion Compensating single-mode Fibre DGD Different
35、ial Group Delay DSF Dispersion Shifted single-mode Fibre DWDM Dense Wavelength Division Multiplexing DWDM S Dense Wavelength Division Multiplexing System FWM Four-Wave Mixing LEF Large Effective area single-mode Fibre MPI Main Path Interface MUX Multiplexer NDF Negative Dispersion single-mode Fibre
36、NRZ Non-Return to Zero NZDSF Non-Zero Dispersion Shifted single-mode Fibre OA Optical Amplifier Rec. ITU-T G.973.1 (11/2009) 3 OTH Optical Transport Hierarchy PMD Polarization Mode Dispersion RZ Return to Zero SDH Synchronous Digital Hierarchy TTE Terminal Transmission Equipment WDMS Wavelength Divi
37、sion Multiplexing System WNZDF Wideband Non-Zero Dispersion single-mode Fibre 5 Conventions This clause is intentionally left blank. 6 Classification of optical interfaces 6.1 Applications This Recommendation addresses longitudinally compatible DWDM application in point-to-point repeaterless optical
38、 fibre submarine cable system. 6.2 Reference configurations For the purpose of this Recommendation, the relevant reference points applicable to the DWDM application for point-to-point repeaterless optical fibre submarine cable systems are shown in Figure 6-1. Tx1Txn MUX MPI-SMRx1RxnD E M U X OA MPI-
39、RMRx1Rxn DEM U X OAMPI-RMTx1TxnM U X OA MPI-SMOA Figure 6-1 Reference configuration for DWDM system The reference points MPI-SMand MPI-RMin Figure 6-1 are defined as follows, using the same nomenclature as in ITU-T G.959.1: MPI-SMis a (multichannel) reference point on the optical fibre just after th
40、e optical network element transport interface output optical connector; 4 Rec. ITU-T G.973.1 (11/2009) MPI-RMis a (multichannel) reference point on the optical fibre just before the optical network element transport interface input optical connector. 7 Single-span longitudinal compatibility The appl
41、ications covered by this Recommendation are single-span longitudinally compatible. It is defined as follows. The systems are defined to be “longitudinally compatible“ when both ends of an optical section are terminated by equipment from the same manufacturer. Systems from different vendors can be in
42、stalled on the various optical fibres of the cable. In this case only the cable characteristics (attenuation, dispersion, DGD) are specified. A single-span longitudinally compatible system is illustrated in Figure 7-1. Tx Tx Vendor A Vendor A Tx Rx Vendor B Vendor B Figure 7-1 Single-span longitudin
43、al compatibility NOTE For multi-span systems, longitudinal compatibility is so far impossible to achieve because all fibre pairs make use of the same repeaters. It means that each amplifier module of each fibre is located into the same repeater housing which is supplied by one single vendor. The sam
44、e applies for the other equipment of the wet plant (e.g., equalizers, branching units). 8 Parameters 8.1 Maximum attenuation The maximum attenuation from MPI-SMto MPI-RMis specified for an operating wavelength region, which include loss caused by splices, connectors, optical attenuators and other pa
45、ssive optical devices (if used) as well as fibre loss. The maximum attenuation coefficient of each G.652, G.653, G.654, G.655 and G.656 fibre is specified in the corresponding ITU-T Recommendations. In these Recommendations, the maximum attenuation coefficients at 1550 nm of cabled fibres are specif
46、ied in the 0.22 to 0.4 dB/km range. It should be noted that a submarine transmission system sometimes requires smaller attenuation value. The typical maximum attenuation value is for further study. 8.2 Fibre types In submarine systems, several types of optical fibres are used to construct an optical
47、 path. These include the following: single-mode fibres defined in ITU-T Recommendations: non-dispersion shifted single-mode fibre (SMF) defined in ITU-T G.652; dispersion shifted single-mode fibre (DSF) defined in ITU-T G.653; cut-off shifted single-mode fibre (CSF) defined in ITU-T G.654; non-zero
48、dispersion-shifted single-mode fibre (NZDSF) defined in ITU-T G.655; wideband non-zero dispersion single-mode fibre (WNZDF) defined in ITU-T G.656; Rec. ITU-T G.973.1 (11/2009) 5 positive dispersion single-mode fibre (PDF); negative dispersion single-mode-fibre (NDF); large effective area single-mod
49、e fibre (LEF); dispersion compensating single-mode fibre (DCF). Depending on the system specifications, various combinations of these fibre types may be used to ensure that the system performs correctly. Further information about each type of fibre can be found in ITU-T G.978. 8.3 Wavelength ranges The operating wavelength range consists of one or more of the wavelength bands, as defined in b-ITU-T G-Sup.41. See Table 8-1. Table 8-1 Wavelength rang
