1、 International Telecommunication Union ITU-T G.698.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (12/2006) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Characteristics of optical systems Multichannel DWDM application
2、s with single-channel optical interfaces ITU-T Recommendation G.698.1 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-TRANSMISSION SYSTEMS G.
3、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 RADIOTELEPHONY AND LINE
4、TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 General G.600G.609 Symmetric cable pairs G.610G.619 Land coaxial cable pairs G.620G.629 Submarine cables G.630G.639 Free space optical systems G.640G.649 Optical fibre cables G.650G.659 Characteristics of optical
5、components and subsystems G.660G.679 Characteristics of optical systems G.680G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDI
6、A 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. ITU-T Rec. G.698.1 (12/2006) i ITU-T Recommendation G.698.1 Multichannel DWD
7、M applications with single-channel optical interfaces Summary ITU-T Recommendation G.698.1 provides optical parameter values for physical layer interfaces of dense wavelength division multiplexing (DWDM) systems primarily intended for metro applications. Applications are defined using optical interf
8、ace parameters at the single-channel connection points between optical transmitters and the optical multiplexer, as well as between optical receivers and the optical demultiplexer in the DWDM system. ITU-T Recommendation G.698.1 uses a methodology which fixes the maximum attenuation of the multiplex
9、er/demultiplexer and fibre together and, therefore, does not specify the maximum fibre-link length explicitly. ITU-T Recommendation G.698.1 includes unidirectional DWDM applications at 2.5 and 10 Gbit/s with 100-GHz channel frequency spacing. The latest revision of ITU-T Recommendation G.698.1 inclu
10、des the use of OADMs within the black link. Source ITU-T Recommendation G.698.1 was approved on 14 December 2006 by ITU-T Study Group 15 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.698.1 (12/2006) FOREWORD The International Telecommunication Union (ITU) is the United Na
11、tions specialized agency in the field of telecommunications. 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 telecommunic
12、ations 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 procedur
13、e 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 telecomm
14、unication 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 these m
15、andatory 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 dra
16、ws 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 members o
17、r 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 rep
18、resent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2007 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.698.1 (12
19、/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 3.1 Terms defined elsewhere 2 4 Abbreviations 2 5 Classification of optical interfaces 3 5.1 Applications 3 5.2 Reference points . 3 5.3 Nomenclature . 6 5.4 Single-channel interfaces at the reference points SSand RS7 6 T
20、ransverse compatibility 8 7 Parameter definitions 9 7.1 General information 10 7.2 Interface at point SS10 7.3 Optical path parameters (single span) from SSto RS11 7.4 Interface at point RS14 8 Parameter values. 15 9 Optical safety considerations 20 Appendix I Number of OADMs supported in a link 21
21、I.1 Introduction 21 I.2 Maximum channel insertion loss 21 I.3 Maximum ripple . 21 I.4 Maximum chromatic dispersion. 22 I.5 Reflections 22 I.6 Maximum differential group delay. 22 I.7 Maximum interferometric crosstalk . 23 Bibliography. 24 ITU-T Rec. G.698.1 (12/2006) 1 ITU-T Recommendation G.698.1 M
22、ultichannel DWDM applications with single-channel optical interfaces 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 primarily intended for metro applica
23、tions. This Recommendation defines and provides values for single-channel optical interface parameters of physical point-to-point and ring DWDM applications (with transmission distance in the range of about 30 km to about 80 km) on single-mode optical fibres through the use of the “black-link“ appro
24、ach. Applications containing amplifiers within the black-link are outside of the scope of this Recommendation. This Recommendation describes DWDM systems that include the following features: Channel frequency spacing: 100 GHz and above (defined in ITU-T G.694.1); Bit rate of signal channel: up to 10
25、 Gbit/s. Specifications are organized according to application codes. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were
26、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 listed below. A list of the currently valid ITU-T Recommendati
27、ons 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.652 ITU-T Recommendation G.652 (2005), Characteristics of a single-mode optical fibre and cable. ITU-T G.653 ITU-T Recommendation G.
28、653 (2006), Characteristics of a dispersion-shifted single-mode optical fibre and cable. ITU-T G.655 ITU-T Recommendation G.655 (2006), Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable. ITU-T G.664 ITU-T Recommendation G.664 (2006), Optical safety procedures and r
29、equirements for optical transport systems. ITU-T G.671 ITU-T Recommendation G.671 (2005), Transmission characteristics of optical components and subsystems. ITU-T G.691 ITU-T Recommendation G.691 (2006), Optical interfaces for single-channel STM-64 and other SDH systems with optical amplifiers. ITU-
30、T G.692 ITU-T Recommendation G.692 (1998), Optical interfaces for multichannel systems with optical amplifiers. ITU-T G.694.1 ITU-T Recommendation G.694.1 (2002), Spectral grids for WDM applications: DWDM frequency grid. 2 ITU-T Rec. G.698.1 (12/2006) ITU-T G.709 ITU-T Recommendation G.709/Y.1331 (2
31、003), Interfaces for the Optical Transport Network (OTN). ITU-T G.957 ITU-T Recommendation G.957 (2006), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. ITU-T G.959.1 ITU-T Recommendation G.959.1 (2006), Optical transport network physical layer interfaces
32、. IEC 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 (OFCS). 3 Terms and definitions 3.1 Terms defined elsewhere 3.1.1 This Recommen
33、dation uses the following terms defined in ITU-T G.671: dense wavelength division multiplexing (DWDM); channel insertion loss; reflectance; ripple; channel spacing; differential group delay; reflectance. 3.1.2 This Recommendation uses the following term defined in ITU-T G.694.1: frequency grid. 3.1.
34、3 This Recommendation uses the following term defined in ITU-T G.709: completely standardized OTUk (OTUk). 3.1.4 This Recommendation uses the following terms defined in ITU-T G.957: joint engineering; receiver sensitivity; transverse compatibility. 3.1.5 This Recommendation uses the following terms
35、defined in ITU-T G.959.1: optical tributary signal; optical tributary signal class NRZ 2.5G; optical tributary signal class NRZ 10G. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ASE Amplified Spontaneous Emission BER Bit Error Ratio DGD Differential
36、 Group Delay ITU-T Rec. G.698.1 (12/2006) 3 EX Extinction Ratio FEC Forward Error Correction ffs For further study NA Not Applicable NE Network Element NRZ Non-Return to Zero OA Optical Amplifier OADM Optical Add-Drop Multiplexer OD Optical Demultiplexer OM Optical Multiplexer ONE Optical Network El
37、ement OTUk Completely standardized optical channel transport unit k PMD Polarization Mode Dispersion RPRLink reference point at the DWDM network element aggregate input RPSLink reference point at the DWDM network element aggregate output RSSingle-channel reference point at the DWDM network element t
38、ributary output SSSingle-channel reference point at the DWDM network element tributary input WDM Wavelength Division Multiplexing 5 Classification of optical interfaces 5.1 Applications This Recommendation provides the physical layer parameters and values for single-channel interfaces of DWDM multic
39、hannel optical systems in physical point-to-point and ring applications. These DWDM systems with single-channel interfaces are primarily intended to be used in metropolitan area networks for a variety of clients, services, and protocols. The specification method in this Recommendation uses a “black-
40、link“ approach which means that optical interface parameters for only (single-channel) optical tributary signals are specified. Additional specifications are provided for the black-link parameters such as maximum attenuation, chromatic dispersion, ripple and polarization mode dispersion. This approa
41、ch enables transverse 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 OM and OD are treated as a single set of optical devices and OADMs can be inclu
42、ded. This Recommendation only considers DWDM applications where the black link does not contain optical amplifiers. 5.2 Reference points 5.2.1 Unidirectional applications Figure 5-1 shows a set of reference points, for the linear “black-link“ approach, for single-channel connection (SSand RS) betwee
43、n transmitters (Tx) and receivers (Rx). Here, the DWDM network elements include an OM and an OD, which are used as a pair with the opposing element, and may also include one or more OADMs. 4 ITU-T Rec. G.698.1 (12/2006) Figure 5-1 Linear “black-link“ approach As indicated in Figure 5-1, in cases whe
44、re the transmitter or receiver is some distance from the OM, OD or OADM, the fibre between point SSor RSand the DWDM network element is considered to be part of the black link. Figure 5-2 shows a corresponding set of reference points for the ring “black-link“ approach, for single-channel connection
45、(SSand RS) between transmitters (Tx) and receivers (Rx). Here, the DWDM network elements include two or more OADMs connected in a ring. Figure 5-2 Ring “black-link“ approach ITU-T Rec. G.698.1 (12/2006) 5 These reference models do not include any optical amplifiers in the DWDM system. The reference
46、points in Figures 5-1 and 5-2 are defined as follows: SSis a single-channel reference point at the DWDM network element tributary input; RSis a single-channel reference point at the DWDM network element tributary output; RPSis a link reference point at the DWDM network element aggregate output; RPRi
47、s a link reference point at the DWDM network element aggregate input. Here, single-channel reference points SSand RSare applied to systems for the (linear or ring) “black-link“ approach where every path from SSto its corresponding RSmust comply with the parameter values of the application code. Note
48、 that RPSand RPRare only defined to provide information for the fibre link and not to provide signal characteristics at these points. 5.2.2 Bidirectional applications While this Recommendation does not currently contain any bidirectional applications, it is expected that they will be added in a futu
49、re revision. Figure 5-3 shows a set of reference points, for the single-fibre bidirectional linear “black-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 and may also include one or more OADMs. Figure 5-3 Linear “black-link“ approach for bidirectional applications Figure 5-4 shows a corresponding set of reference poin
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