1、 International Telecommunication Union ITU-T G.651.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(12/2008) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Optical fibre cables Characteristics of a 50/125 m mu
2、ltimode graded index optical fibre cable for the optical access network Amendment 1: New Appendix I Historical perspective on the evolution of the specification of multimode optical fibre cable Recommendation ITU-T G.651.1 (2007) Amendment 1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND ME
3、DIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERIST
4、ICS 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.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 General G.600G.609 Symmetric cable pairs
5、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 components and subsystems G.660G.679 Characteristics of optical systems G.680G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITA
6、L 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 PACKET OVER TRANSPORT ASPECTS G.8000G.8999ACCESS
7、 NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.651.1 (2007)/Amd.1 (12/2008) i Recommendation ITU-T G.651.1 Characteristics of a 50/125 m multimode graded index optical fibre cable for the optical access network Amendment 1 New Appendix I H
8、istorical perspective on the evolution of the specification of multimode optical fibre cable Summary Amendment 1 to Recommendation ITU-T G.651.1 provides background information on the evolution of the specification of multimode optical fibre cable in ITU-T Recommendations. Source Amendment 1 to Reco
9、mmendation ITU-T G.651.1 (2007) was agreed on 12 December 2008 by ITU-T Study Group 15 (2009-2012). ii Rec. ITU-T G.651.1 (2007)/Amd.1 (12/2008) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and commu
10、nication 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 telecommunications on a worldwide basis. Th
11、e 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 in WTSA Resolution
12、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 administration and a
13、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 provisions are met. Th
14、e 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 attention to the possibility
15、 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 outside of the Recomme
16、ndation 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 represent the latest information a
17、nd are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2009 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.651.1 (2007)/Amd.1 (12/2008) 1 Recommend
18、ation ITU-T G.651.1 Characteristics of a 50/125 m multimode graded index optical fibre cable for the optical access network Amendment 1 New Appendix I Historical perspective on the evolution of the specification of multimode optical fibre cable Recommendation ITU-T G.651 “Characteristics of a 50/125
19、 m multimode graded index optical fibre cable“ Recommendation ITU-T G.651, originally published in 1980, covered the geometrical and transmissive properties of multimode fibres having a 50 m nominal core diameter and a 125 m nominal cladding diameter. Test methods and the meanings of the terms used
20、were in the text. That Recommendation, which had not been significantly changed from the original in the four subsequent editions through 1998, was developed during the infancy of optical fibre solutions for publicly switched networks. At that time (pre-1984), these fibres were considered as the onl
21、y practical solution for transmission distances in the 10s of kilometres and bit-rates of up to 40 Mbit/s. Single-mode ITU-T G.652 fibres, which became available shortly after the publication of Recommendation ITU-T G.651, have almost completely replaced multimode fibres in the public switched netwo
22、rks. Today, multimode fibres continue to be widely used in premises cabling applications such as Ethernet in lengths from 300 to 2000 m, depending on bit rate. With a change in the applications, the multimode fibre definitions, requirements, and measurements evolved away from the original Recommenda
23、tion ITU-T G.651 in some ways and were maintained or improved in others. The transmission characteristics from this Recommendation have also been moved to the modern equivalent, Recommendation ITU-T G.651.1. A complete documentation for the modern requirements is found in IEC 60793-2-10. The content
24、s of Recommendation ITU-T G.651 included the early parameter definitions for glass geometry, numerical aperture, attenuation and baseband response (the combination of modal bandwidth and chromatic dispersion). Some limits on these parameters were also given. Formulas for the attenuation and bandwidt
25、h of installed links comprised of concatenations of cables were given. Measurement methods for the parameters were described. Some differences between Recommendation ITU-T G.651 and the modern requirements include: i) the core diameter is defined in terms of the near field profile, rather than the r
26、efractive index profile; ii) parameters such as core/cladding tolerance field and intrinsic quality factor are no longer used; iii) the prooftest stress is now twice what it was; iv) bandwidth limits were then 200 MHz km, where as now limits can be as large as 2000 MHz km. 2 Rec. ITU-T G.651.1 (2007
27、)/Amd.1 (12/2008) With the acceptance of more modern and more tightly specified Recommendation ITU-T G.651.1 in 2007, the old Recommendation ITU-T G.651 was felt to be obsolete, and therefore was withdrawn in February 2008. This appendix indicates some background information about the old Recommenda
28、tion ITU-T G.651. Table I.1 Fibre characteristics of the withdrawn Recommendation ITU-T G.651 Attribute Detail Value Nominal 125 m Cladding diameter Tolerance 3 m Nominal 50 mCore diameter Tolerance 3 m Core-cladding concentricity error Maximum 6% Core non-circularity Maximum 6% Cladding non-circula
29、rity Maximum 2% Nominal 0.20 or 0.23 Numerical aperture Tolerance 0.02 Proof stress Minimum 0.35 GPa Minimum at 850 nm 200 MHz km Modal bandwidth-length product for overfilled launch Minimum at 1300 nm 200 MHz km Typical at 850 nm 120 ps/(nm km) Chromatic dispersion coefficient Typical at 1300 nm 6
30、ps/(nm km) Cable attributes Attribute Detail Value Maximum at 850 nm 4 dB/km Attenuation coefficient Maximum at 1300 nm 2 dB/km Printed in Switzerland Geneva, 2009 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network o
31、peration, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks an
32、d transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N M
33、aintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph ser
34、vices terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
