1、 International Telecommunication Union ITU-T G.691TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2006) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media characteristics Characteristics of optical components and subsystems Optical interfaces for single cha
2、nnel STM-64 and other SDH systems with optical amplifiers ITU-T Recommendation G.691 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-TRANSMIS
3、SION 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 RADIOTELE
4、PHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA 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.649 Optical fibre cables G.650G.659 Characteristics of optical components and subsystems G.660G.699 DIGITA
5、L 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 MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 ETHERNET
6、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.691 (03/2006) i ITU-T Recommendation G.691 Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers Summary This Rec
7、ommendation provides parameters and values for optical interfaces of single-channel long-haul STM-4, STM-16 and STM-64 systems utilizing optical preamplifiers and/or optical booster amplifiers. Furthermore, it provides optical interface parameters for single-channel STM-64 intra-office and short-hau
8、l systems without optical amplification Source ITU-T Recommendation G.691 was approved on 29 March 2006 by ITU-T Study Group 15 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.691 (03/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations speci
9、alized 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 telecommunications on a
10、 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 procedure laid down
11、 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 telecommunication a
12、dministration 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 mandatory pr
13、ovisions 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 draws attentio
14、n 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 or others ou
15、tside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the late
16、st information and are therefore strongly urged to consult the TSB patent database. ITU 2006 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.691 (03/2006) iii CONTENTS Page 1 Scope 1 2 References.
17、1 3 Terms and definitions . 2 3.1 Definitions 2 3.2 Terms defined in other Recommendations. 2 4 Abbreviations 3 5 Classification of optical interfaces 4 5.1 Applications 4 5.2 Reference and physical configurations. 6 6 Parameter definitions 7 6.1 System operating wavelength range. 7 6.2 Transmitter
18、. 7 6.3 Optical path 10 6.4 Receiver 13 7 Optical parameter values 14 8 Optical engineering approach. 20 8.1 Design assumptions 20 8.2 Non-linearities 21 8.3 Dispersion accommodation 21 8.4 Stand-alone amplifiers 24 8.5 Upgradability considerations 24 8.6 Optical safety considerations 25 Annex A Ext
19、inction ratio and eye mask penalties 25 A.1 Measurement parameters 25 A.2 Extinction ratio penalty 26 A.3 Eye mask penalty 26 A.4 Receiver sensitivity 27 Appendix I Polarization mode dispersion. 27 I.1 The statistical distribution of PMD 27 I.2 The path penalty due to PMD. 29 Appendix II Description
20、 of SPM as dispersion accommodation 30 II.1 SPM basics . 30 II.2 Using self phase modulation as a dispersion accommodation technique. 30 II.3 SPM-breakdown. 31 II.4 Optical parameter values for applications 31 II.5 Source type . 31 II.6 Eye pattern mask 31 iv ITU-T Rec. G.691 (03/2006) Page II.7 Rec
21、eiver 31 Appendix III Dispersion accommodation by means of DST 32 III.1 Introduction 32 III.2 Principle of the DST technique 32 III.3 Optical receiver eye pattern mask after dispersive fibre transmission. 33 III.4 Parameter definitions 34 III.5 Optical parameter values 37 Appendix IV Measurement of
22、the chirp parameter of the optical transmit signal 38 IV.1 Measurement set-up 38 IV.2 Technical requirements for the measuring equipment . 39 IV.3 Calibration 39 IV.4 Measurement procedure . 40 IV.5 Data processing 40 IV.6 Examples and interpretation of data. 41 Appendix V Upgradability consideratio
23、ns 42 ITU-T Rec. G.691 (03/2006) 1 ITU-T Recommendation G.691 Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers 1 Scope The purpose of this Recommendation is to provide optical interface specifications to enable transverse (multi-vendor) compatibility of sing
24、le-channel STM-4, STM-16, and STM-64 inter-office systems using optical preamplifiers and/or optical booster amplifiers. Specifications to enable transversely compatible single-channel STM-64 intra-office and short-haul systems not requiring optical amplification are also included. The use of line a
25、mplifiers is not within the scope of this Recommendation. This Recommendation is based on the use of one fibre per direction. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation.
26、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 listed
27、 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. 1 ITU-T Recommendation G.652 (2005), Characteristics of a single-mode optical fibre
28、and cable. 2 ITU-T Recommendation G.653 (2003), Characteristics of a dispersion-shifted single-mode optical fibre and cable. 3 ITU-T Recommendation G.655 (2006), Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable. 4 ITU-T Recommendation G.662 (2005), Generic charact
29、eristics of optical amplifier devices and subsystems. 5 ITU-T Recommendation G.663 (2000), Application related aspects of optical amplifier devices and subsystems. 6 ITU-T Recommendation G.664 (2006), Optical safety procedures and requirements for optical transport systems. 7 ITU-T Recommendation G.
30、671 (2005), Transmission characteristics of optical components and subsystems. 8 ITU-T Recommendation G.693 (2005), Optical interfaces for intra-office systems. 9 ITU-T Recommendation G.707/Y.1322 (2003), Network node interface for the synchronous digital hierarchy (SDH). 2 ITU-T Rec. G.691 (03/2006
31、) 10 ITU-T Recommendation G.955 (1996), Digital line systems based on the 1544 kbit/s and the 2048 kbit/s hierarchy on optical fibre cables. 11 ITU-T Recommendation G.957 (2006), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. 12 ITU-T Recommendation G.95
32、9.1 (2006), Optical transport network physical layer interfaces. 3 Terms and definitions 3.1 Definitions This Recommendation defines the following terms: 3.1.1 main (optical) path: The fibre plant between the S point of the transmitter equipment and the R point of the receiver equipment. The main pa
33、th does not include any auxiliary paths. 3.1.2 main path interfaces: The interfaces to the fibre plant specified in this Recommendation. 3.1.3 auxiliary (optical) path: The optical interconnection between a non-amplified transmitter or receiver and an (stand-alone) optical pre- or booster-amplifier
34、device. An auxiliary path is not included in the main path. 3.1.4 (optical) transponder: A transmitter-receiver combination with or without pulse shaping and retiming that converts an optical signal into another optical signal by a conversion into the electrical domain. 3.2 Terms defined in other Re
35、commendations This Recommendation uses the following terms defined in other ITU-T Recommendations: Booster amplifier: (ITU-T Rec. G.662) Erbium doped fibre amplifier: (ITU-T Rec. G.661) Joint engineering: (ITU-T Rec. G.957) Longitudinal compatibility: (ITU-T Rec. G.955) Optical amplifier device: (IT
36、U-T Rec. G.662) Optical amplifier subsystem: (ITU-T Rec. G.662) Optical amplifier: (ITU-T Rec. G.662) Optical fibre amplifier: (ITU-T Rec. G.662) Optical return loss: (ITU-T Rec. G.957) Optically amplified receiver: (ITU-T Rec. G.662) Optically amplified transmitter: (ITU-T Rec. G.662) Pre-amplifier
37、: (ITU-T Rec. G.662) S/R reference points: (ITU-T Rec. G.955) Transverse compatibility: (ITU-T Rec. G.957) ITU-T Rec. G.691 (03/2006) 3 4 Abbreviations This Recommendation uses the following abbreviations: APD Avalanche Photo Diode ASE Amplified Spontaneous Emission ASK Amplitude Shift Keying BER Bi
38、t Error Ratio DA Dispersion Accommodation DGD Differential Group Delay DST Dispersion Supported Transmission EX Extinction ratio FEC Forward Error Correction ffs For Further Study FM Frequency Modulation FSK Frequency Shift Keying FSR Free Spectral Range FWHM Full Width at Half Maximum I Intra-Offic
39、e IM Intensity Modulation L Long-Haul MLM Multi-Longitudinal Mode MPI Main Path Interface MPN Mode Partition Noise NA Not Applicable NRZ Non-Return to Zero ORL Optical Return Loss PCH Prechirp PDC Passive Dispersion Compensator PIN “p-type“ intrinsic “n-type“ PMD Polarization Mode Dispersion PRBS Ps
40、eudo-Random Binary Sequence PSP Principal State of Polarization RMS Root Mean Square S Short-Haul SDH Synchronous Digital Hierarchy SLM Single-Longitudinal Mode SMSR Side Mode Suppression Ratio SNR Signal to Noise Ratio 4 ITU-T Rec. G.691 (03/2006) SOP State of Polarization SPM Self Phase Modulation
41、 STM-N Synchronous Transport Module of order N U Ultra Long-Haul V Very Long-Haul WDM Wavelength Division Multiplex 5 Classification of optical interfaces 5.1 Applications This Recommendation defines optical interfaces for single-channel inter-office line systems for terrestrial long-distance applic
42、ations from STM-4 to STM-64. It is an extension of ITU-T Rec. G.957 based on the addition of optical amplifiers and the STM-64 data rate. Systems with line amplifiers are not within the scope of this Recommendation. The definitions of the application codes are extended from ITU-T Rec. G.957 as: Appl
43、ication STM level.suffix number, where “application“ corresponds to the target distance: I- (Intra-office), S- (Short-haul), L- (Long-haul), V- (Very long-haul), and U- (Ultra long-haul). The suffix number denotes: 1 the use of nominally 1310 nm sources on G.652 (standard) fibre; 2 the use of nomina
44、lly 1550 nm sources on G.652 fibre; 3 the use of nominally 1550 nm sources on G.653 (dispersion shifted) fibre; 5 the use of nominally 1550 nm sources on G.655 (non-zero dispersion shifted) fibre. For some I-64 codes an “r“ is added after the suffix number to indicate a reduced target distance. Thes
45、e application codes which belong to the intra-office family are dispersion limited. The same target distance can be achieved by means of other technological solutions, which are for further study (e.g., parallel interface approach). The target distances are based on approximately 40 km intervals for
46、 1550 nm and 20 km intervals for 1310 nm, except for the very short reach and intra-office applications. The target distances are to be used for classification only and not for specification. They are estimated using the assumption of 0.275 dB/km installed fibre loss including splices and cable marg
47、ins for 1550 nm systems, and 0.55 dB/km for 1310 nm systems. From a practical point of view, attenuation spans of 11 dB/20 km at 1310 nm and 11 dB/40 km at 1550 nm are defined, except for very short reach and intra-office applications. In practice, these values may not apply to all fibre cables, in
48、which case the realistic distances that can be reached may be shorter. The primary specifications are the attenuation range and the maximum dispersion tolerance of the system. The main use of the target distance is to define the dispersion tolerance, which is calculated as the maximum fibre dispersi
49、on times the target distance. This gives added tolerance to the systems, as well as enabling the full utilization of low attenuation fibre plants. Tables 1a, 1b and 1c summarize the application codes described in this Recommendation. 5 ITU-T Rec. G.691 (03/2006) Table 1a/G.691 Classification of optical interfaces based on application and showing I application codes Applications Source nominal wavelength nm 1310 1310 1550 1550 1550 1550 Fibre type G.652 G.652 G.652 G.652 G.653 G.655 Targ dist. km 0.6 2 2
