1、 International Telecommunication Union ITU-T G.698.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2009) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Characteristics of optical systems Amplified multichannel dense
2、wavelength division multiplexing applications with single channel optical interfaces Recommendation ITU-T G.698.2 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 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 c
5、ables G.650G.659 Characteristics of optical components and subsystems G.660G.679 Characteristics of optical systems G.680G.699DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC A
6、ND USER-RELATED ASPECTS 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.698.2 (11
7、/2009) i Recommendation ITU-T G.698.2 Amplified multichannel dense wavelength division multiplexing applications with single channel optical interfaces Summary Recommendation ITU-T G.698.2 provides optical parameter values for physical layer interfaces of dense wavelength division multiplexing (DWDM
8、) systems primarily intended for metro applications which include optical amplifiers. Applications are defined using optical interface parameters at the single-channel connection points between optical transmitters and the optical multiplexer, as well as between optical receivers and the optical dem
9、ultiplexer in the DWDM system. This Recommendation uses a methodology which does not specify the details of the optical link, e.g., the maximum fibre length, explicitly. This version of this Recommendation includes unidirectional DWDM applications at 2.5 and 10 Gbit/s with 100 GHz channel frequency
10、spacing as well as applications at 10 Gbit/s with 50 GHz channel frequency spacing. Source Recommendation ITU-T G.698.2 was approved on 13 November 2009 by ITU-T Study Group 15 (2009-2012) under Recommendation ITU-T A.8 procedures. ii Rec. ITU-T G.698.2 (11/2009) FOREWORD The International Telecommu
11、nication Union (ITU) is the United Nations specialized agency in the field of telecommunications, 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
12、 questions and issuing Recommendations on them with a view to standardizing telecommunications 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 Recommend
13、ations 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 purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendat
14、ion, the expression “Administration“ is used for conciseness to indicate both a telecommunication 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
15、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“ and the negative equivalents are used to express requirements. The use of such words does not suggest that complianc
16、e 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 involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or
17、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 Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to
18、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 at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by a
19、ny means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.698.2 (11/2009) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acronyms 3 5 Classification of optical
20、 interfaces 3 5.1 Applications 3 5.2 Reference points . 4 5.3 Nomenclature . 7 5.4 Single-channel interfaces at the reference points SSand RS 8 6 Transverse compatibility 9 7 Parameter definitions 9 7.1 General information 10 7.2 Interface at point SS . 11 7.3 Optical path parameters from SSto RS 13
21、 7.4 Interface at point RS . 16 8 Parameter values . 18 9 Optical safety considerations 25 Appendix I Measurement of transmitter (residual) dispersion OSNR penalty and optical path OSNR penalty . 26 Appendix II Transponder elimination via single channel DWDM interfaces 28 Bibliography. 30 Rec. ITU-T
22、 G.698.2 (11/2009) 1 Recommendation ITU-T G.698.2 Amplified multichannel dense wavelength division multiplexing applications with single channel optical interfaces 1 Scope The purpose of this Recommendation is to provide optical interface specifications towards the realization of transversely compat
23、ible dense wavelength division multiplexing (DWDM) systems primarily intended for metro applications which include optical amplifiers. This Recommendation defines and provides values for single-channel optical interface parameters of physical point-to-point and ring DWDM applications on single-mode
24、optical fibres through the use of the “black link“ approach. The black links covered by this Recommendation may contain optical amplifiers. The use of these single channel optical interfaces for DWDM systems enables the elimination of transponders which would otherwise be needed in multivendor DWDM
25、optical transmission networks. Further details can be found in Appendix II. This Recommendation describes single channel interfaces to DWDM systems that include the following features: channel frequency spacing: 50 GHz and wider (defined in ITU-T G.694.1); bit rate of signal channel: Up to 10 Gbit/s
26、. Future revisions of this Recommendation are expected to include application codes for bit rates up to 40 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 te
27、xt, 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 possibility of applying the most recent edition
28、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 Recommendation. ITU-T G.652 Recommendation ITU-T G
29、.652 (2005), 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 optical fibre and cable. ITU-T G.655 Recommendation ITU-T G.655 (2006), Characteristics of a non-zero dispersion-shifted single-mo
30、de optical fibre and cable. ITU-T G.664 Recommendation ITU-T G.664 (2006), Optical safety procedures and requirements for optical transport systems. ITU-T G.671 Recommendation ITU-T G.671 (2009), Transmission characteristics of optical components and subsystems. ITU-T G.691 Recommendation ITU-T G.69
31、1 (2006), Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers. 2 Rec. ITU-T G.698.2 (11/2009) ITU-T G.692 Recommendation ITU-T G.692 (1998), Optical interfaces for multichannel systems with optical amplifiers. ITU-T G.694.1 Recommendation ITU-T G.694.1 (2002),
32、Spectral grids for WDM applications: DWDM frequency grid. ITU-T G.709 Recommendation ITU-T G.709/Y.1331 (2003), Interfaces for the Optical Transport Network (OTN). ITU-T G.957 Recommendation ITU-T G.957 (2006), Optical interfaces for equipments and systems relating to the synchronous digital hierarc
33、hy. ITU-T G.959.1 Recommendation ITU-T G.959.1 (2008), Optical transport network physical layer interfaces. 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 f
34、ibre communication systems (OFCS). 3 Terms and definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined in ITU-T Rec. G.671: Dense Wavelength Division Multiplexing (DWDM); Channel insertion loss; Reflectance; Ripple; Channel spacing; Differential group delay; Refl
35、ectance. This Recommendation uses the following term defined in ITU-T Rec. G.691: (Optical) transponder. This Recommendation uses the following term defined in ITU-T Rec. G.694.1: Frequency grid. This Recommendation uses the following term defined in ITU-T Rec. G.709/Y.1331: Completely standardized
36、OTUk (OTUk). This Recommendation uses the following terms defined in ITU-T Rec. G.957: Joint engineering; Transverse compatibility. This Recommendation uses the following terms defined in ITU-T Rec. G.959.1: Optical tributary signal; Optical tributary signal class NRZ 2.5G; Optical tributary signal
37、class NRZ 10G. Rec. ITU-T G.698.2 (11/2009) 3 3.2 Terms defined in this Recommendation This Recommendation does not define any terms. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: APD Avalanche Photodiode ASE Amplified Spontaneous Emission BER Bit Er
38、ror Ratio DGD Differential Group Delay EX Extinction ratio FEC Forward Error Correction 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 Element OTUk Completely stand
39、ardized optical channel transport unit k PDL Polarization Dependent Loss PIN P type-intrinsic-n type PMD Polarization Mode Dispersion RSSingle-channel reference point at the DWDM network element tributary output SOP State of Polarization SSSingle-channel reference point at the DWDM network element t
40、ributary input VOA Variable Optical Attenuator 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 multichannel optical systems in physical point-to-po
41、int and ring 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. Additional specifications are provided for the black link parameters, such as resi
42、dual chromatic dispersion, ripple and polarization mode dispersion. This approach 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. 4 Rec. ITU-T G.698.2 (
43、11/2009) This Recommendation considers DWDM applications where the black link may 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) between tran
44、smitters (Tx) and receivers (Rx). Here the DWDM network elements include an optical multiplexer (OM) and an optical demultiplexer (OD) (which are used as a pair with the opposing element), one or more optical amplifiers and may also include one or more optical add-drop multiplexers (OADMs). The arra
45、ngement of elements within the black link shown in Figures 5-1 to 5-4 is not intended to place constraints on the construction of the black link, but simply to define the location of the single channel interfaces. G.698.2(09)_F5-1Tx 1Tx 2Tx NSSSSSSOMDWDM linkOADM ODRx 1Rx 2Rx NRSRSRSSSRSRxXTxYDWDM n
46、etwork elementsFigure 5-1 Linear “black link“ approach As indicated in Figure 5-1, in cases where 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 correspon
47、ding set of reference points for the ring “black link“ approach, for single-channel connection (SSand RS) between transmitters (Tx) and receivers (Rx). Here the DWDM network elements include one or more amplifiers and two or more OADMs connected in a ring. Rec. ITU-T G.698.2 (11/2009) 5 G.698.2(09)_
48、F5-2SSSSSSDWDM linkRSRSRSRx TxDWDM network elementsTxTxTxRSSSOADMRxRxRxOADMOADMOADMFigure 5-2 Ring “black link“ approach The reference 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 refere
49、nce point at the DWDM network element tributary output. 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. 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 future revisio
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