1、 International Telecommunication Union ITU-T G.973TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2010) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Optical fibre submarine cable systems Characteristics of repeaterless optical fi
2、bre submarine cable systems Recommendation ITU-T G.973 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-TRANSMISSION SYSTEMS G.200G.299 INDIVI
3、DUAL 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 RADIOTELEPHONY AND LINE TELEPHONY G.450
4、G.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 Digital sections at hierarchical bit
5、 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 transmission systems for customer
6、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 MEDIA CHARACTERISTICS G.6000G.69
7、99 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 (07/2010) i Recommendation ITU-T G.973 Characteristics of repeaterless optical fibre su
8、bmarine cable systems Summary Recommendation ITU-T G.973 is concerned primarily with the system performance and interface requirements of repeaterless optical fibre submarine cable systems. It considers both single wavelength systems (SWS) and wavelength division multiplexing systems (WDMS). It also
9、 covers the aspects related to the applications of discrete optical fibre amplifiers (OFAs) (power amplifiers, pre-amplifiers, remote optically pumped amplifiers) and/or distributed remotely pumped OFAs using Raman amplification. History Edition Recommendation Approval Study Group 1.0 ITU-T G.973 19
10、96-11-11 15 2.0 ITU-T G.973 2003-12-14 15 3.0 ITU-T G.973 2007-07-29 15 4.0 ITU-T G.973 2010-07-29 15 ii Rec. ITU-T G.973 (07/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication tech
11、nologies (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 telecommunications on a worldwide basis. The World Telec
12、ommunication 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 procedure laid down in WTSA Resolution 1. In some ar
13、eas 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 telecommunication administration and a recognized op
14、erating 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 these mandatory provisions are met. The words “sh
15、all“ 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 draws attention to the possibility that the p
16、ractice 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 members or others outside of the Recommendation dev
17、elopment 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 represent the latest information and are ther
18、efore 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 (07/2010) iii CONTENTS Page 1 Scope 1 2 Referen
19、ces. 1 3 Definitions 3 3.1 Terms defined elsewhere 3 3.2 Terms defined in this Recommendation . 4 4 Abbreviations and acronyms 4 5 Conventions 5 6 Characteristics and performance of the system 5 6.1 Characteristics and performance of the digital line sections (DLS) . 5 6.2 Characteristics and perfor
20、mance of the optical sections 7 6.3 System reliability performance . 9 6.4 System capacity upgradeability 9 7 Characteristics and performance of the TTE 10 7.1 General . 10 7.2 Transmission performance . 10 7.3 Actions consequent to an alarm 11 7.4 Automatic switching . 11 8 Characteristics and perf
21、ormance of the submarine cable . 11 8.1 Dispersion mapping 11 8.2 Dispersion management implementation . 12 Annex A Implementation of repeaterless optical fibre submarine cable systems 13 A.1 Introduction 13 A.2 System configuration 15 A.3 Characteristics of the line signal . 17 A.4 System operation
22、 18 A.5 Passive branching unit characteristics 18 Annex B Repeaterless optical fibre submarine cable systems using ROPA: Optical power budget between optical reference points S and R and line monitoring . 19 B.1 Remote optically pumped amplifiers (ROPAs) 19 B.2 Optical power budget for systems using
23、 ROPA . 19 B.3 Line monitoring for pumping portion . 20 Bibliography. 22 Rec. ITU-T G.973 (07/2010) 1 Recommendation ITU-T G.973 Characteristics of repeaterless optical fibre submarine cable systems 1 Scope This Recommendation is concerned primarily with the system performance and interface requirem
24、ents of repeaterless optical fibre submarine cable systems; it considers both single wavelength systems (SWS) and wavelength division multiplexing systems (WDMS). It also covers the aspects related to the applications of discrete optical fibre amplifiers (OFAs) as power amplifiers, pre-amplifiers an
25、d/or remote optically pumped amplifiers (ROPA) (either erbium-doped transmission fibres using remote pumping from the terminal or using the distributed Raman amplification pumped from the terminal). The purpose of a repeaterless optical fibre submarine cable system is to establish transmission links
26、 between two or more terminal stations located in a restricted geographical area. A cable system connecting only two terminal stations may be termed an “optical fibre submarine cable link“. When it connects more than two terminal stations, it may be termed an “optical fibre submarine cable network“.
27、 In a repeaterless submarine cable system, no power feeding equipment (PFE) is necessary as there is no in-line OFA. As far as the branching unit devices are concerned, those considered in this Recommendation are the passive ones, therefore avoiding electronic components as well as supervisory and p
28、ower feeding. Common implementation aspects of optical submarine cable systems for manufacturing, installing and maintenance are described in ITU-T G.971. ITU-T G.978 also contains common aspects of the characteristics of the optical fibre submarine cables. The physical implementation of repeaterles
29、s optical fibre submarine cable systems and the implications of the use of ROPA are considered respectively in Annexes A and B. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation
30、. 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 references list
31、ed 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.661 Recommendation ITU-T G.661 (2007), Definition and test methods for the
32、 relevant generic parameters of optical amplifier devices and subsystems. ITU-T G.662 Recommendation ITU-T G.662 (2005), Generic characteristics of optical amplifier devices and subsystems. ITU-T G.664 Recommendation ITU-T G.664 (2006), Optical safety procedures and requirements for optical transpor
33、t systems. ITU-T G.665 Recommendation ITU-T G.665 (2005), Generic characteristics of Raman amplifiers and Raman amplified subsystems. 2 Rec. ITU-T G.973 (07/2010) ITU-T G.692 Recommendation ITU-T G.692 (1998), Optical interfaces for multichannel systems with optical amplifiers. ITU-T G.698.1 Recomme
34、ndation ITU-T G.698.1 (2009), Multichannel DWDM applications with single-channel optical interfaces. ITU-T G.701 Recommendation ITU-T G.701 (1993), Vocabulary of digital transmission and multiplexing, and pulse code modulation (PCM) terms. ITU-T G.702 Recommendation ITU-T G.702 (1988), Digital hiera
35、rchy bit rates. ITU-T G.703 Recommendation ITU-T G.703 (2001), Physical/electrical characteristics of hierarchical digital interfaces. ITU-T G.707 Recommendation ITU-T G.707/Y.1322 (2007), Network node interface for the synchronous digital hierarchy (SDH). ITU-T G.709 Recommendation ITU-T G.709/Y.13
36、31 (2009), Interfaces for the Optical Transport Network (OTN). ITU-T G.780 Recommendation ITU-T G.780/Y.1351 (2008), Terms and definitions for synchronous digital hierarchy (SDH) networks. ITU-T G.821 Recommendation ITU-T G.821 (2002), Error performance of an international digital connection operati
37、ng at a bit rate below the primary rate and forming part of an Integrated Services Digital Network. ITU-T G.823 Recommendation ITU-T G.823 (2000), The control of jitter and wander within digital networks which are based on the 2048 kbit/s hierarchy. ITU-T G.825 Recommendation ITU-T G.825 (2000), The
38、 control of jitter and wander within digital networks which are based on the synchronous digital hierarchy (SDH). ITU-T G.826 Recommendation ITU-T G.826 (2002), End-to-end error performance parameters and objectives for international, constant bit-rate digital paths and connections. ITU-T G.828 Reco
39、mmendation ITU-T G.828 (2000), Error performance parameters and objectives for international, constant bit-rate synchronous digital paths. ITU-T G.921 Recommendation ITU-T G.921 (1988), Digital sections based on the 2048 kbit/s hierarchy. ITU-T G.955 Recommendation ITU-T G.955 (1996), Digital line s
40、ystems based on the 1544 kbit/s and the 2048 kbit/s hierarchy on optical fibre cables. 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 netw
41、ork physical layer interfaces. ITU-T G.971 Recommendation ITU-T G.971 (2007), General features of optical fibre submarine cable systems. ITU-T G.972 Recommendation ITU-T G.972 (2008), Definition of terms relevant to optical fibre submarine cable systems. ITU-T G.975 Recommendation ITU-T G.975 (2000)
42、, Forward error correction for submarine systems. ITU-T G.975.1 Recommendation ITU-T G.975.1 (2004), Forward error correction for high bit-rate DWDM submarine systems. Rec. ITU-T G.973 (07/2010) 3 ITU-T G.978 Recommendation ITU-T G.978 (2006), Characteristics of optical fibre submarine cables. ITU-T
43、 G.8201 Recommendation ITU-T G.8201 (2003), Error performance parameters and objectives for multi-operator international paths within the Optical Transport Network (OTN). ITU-T G.8251 Recommendation ITU-T G.8251 (2001), The control of jitter and wander within the optical transport network (OTN). IEC
44、 60825-1 IEC 60825-1 (2007), Safety of laser products Part 1: Equipment classification and requirements. IEC 60825-2 IEC 60825-2 (2007), Safety of laser products Part 2: Safety of optical fibre communication systems (OCFS). 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the follo
45、wing terms defined elsewhere: 3.1.1 cable breaking load ITU-T G.972 3.1.2 digital line section (DLS) ITU-T G.701 3.1.3 double armoured cable ITU-T G.972 3.1.4 fibre-breaking cable load ITU-T G.972 3.1.5 intermediate terrestrial interface (ITI) ITU-T G.972 3.1.6 minimum cable bending radius ITU-T G.9
46、72 3.1.7 multiplex section overhead (MSOH) ITU-T G.780 3.1.8 nominal operating tensile strength ITU-T G.972 3.1.9 nominal permanent tensile strength ITU-T G.972 3.1.10 nominal transient tensile strength ITU-T G.972 3.1.11 optical fibre amplifier (OFA) ITU-T G.661 3.1.12 receive main path interface r
47、eference point (MPI-R) ITU-T G.959.1 3.1.13 rock armoured cable ITU-T G.972 3.1.14 S, R reference points ITU-T G.662 3.1.15 S, R reference points ITU-T G.955 and ITU-T G.957 3.1.16 single armoured cable ITU-T G.972 3.1.17 source main path interface reference point (MPI-S) ITU-T G.959.1 3.1.18 submar
48、ine cable optical interface (SCOI) ITU-T G.977 3.1.19 submarine electro-optic interface (SEOI) ITU-T G.977 3.1.20 synchronous digital hierarchy (SDH) ITU-T G.780 3.1.21 synchronous transport module (STM) ITU-T G.780 3.1.22 terrestrial interface (TI) ITU-T G.972 4 Rec. ITU-T G.973 (07/2010) Tx1 . . .
49、 Tx2 TxNRx1 . . . Rx2 RxNMPI-S MPI-RS1 S2 Sn R1 R2 Rn Optical mux/demux DLSOptical mux/demux SEOI SEOI SCOISCOI Figure 1 Representation of optical line system interfaces (multichannel system) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 branching unit (BU): A passive optical submarine piece of equipment inserted into the submarine portion of an optical fibre submarine cab
