1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T G.657 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2016) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Optical fibre cables Characterist
2、ics of a bending-loss insensitive single-mode optical fibre and cable Recommendation ITU-T G.657 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 CARR
3、IER-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.449 COORDINATION
4、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 cables G.650G.659
5、Characteristics of optical 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 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED
6、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.657 (11/2016) i Recommend
7、ation ITU-T G.657 Characteristics of a bending-loss insensitive single-mode optical fibre and cable Summary Worldwide, technologies for general transport network and broadband access networks are advancing rapidly. Among these, the technology applying single-mode fibre provides for a high-capacity t
8、ransmission medium which can answer the growing demand for high speed and broadband services. The experience with the installation and operation of single-mode fibre and cable-based networks is huge and Recommendation ITU-T G.652, which describes its characteristics, has been adapted to this experie
9、nce. Nevertheless, the specific use in an optical access network puts different demands on the fibre and cable which impacts its optimal performance characteristics. Differences with respect to the use in the general transport network are mainly due to the high density network of distribution and dr
10、op cables in the access network. The limited space and the many manipulations ask for operator-friendly fibre performance and low bending sensitivity. In addition, the cabling in the crowded telecom offices where space is a limiting factor has to be improved accordingly. Yet, certain areas of the ge
11、neral transport network can also be described as space limited, where bend optimized cabling can be advantageous. It is the aim of Recommendation ITU-T G.657 to support this optimization by recommending strongly improved bending performance compared with the existing ITU-T G.652 single-mode fibre an
12、d cables. This is done by means of two categories of single-mode fibres, one of which, category A, is fully compliant with the ITU-T G.652 single-mode fibres and can be deployed throughout the general transport network as well as the access network. The other, category B, is not necessarily complian
13、t with Recommendation ITU-T G.652, but is capable of low values of macrobending losses at very low bend radii and is intended for application in the access network inside buildings or near buildings (e.g., outside building riser cabling). These category B fibres are system compatible with ITU-T G.65
14、7.A (and ITU-T G.652.D) fibres in access networks. This fourth edition of Recommendation ITU-T G.657 modifies, amongst other things, the usage of category A fibres for all applications (access networks as well as general transport networks) where ITU-T G.652.D fibres are used, now with improved bend
15、ing characteristics. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.657 2006-12-14 15 11.1002/1000/8976 2.0 ITU-T G.657 2009-11-13 15 11.1002/1000/10391 2.1 ITU-T G.657 (2009) Amd. 1 2010-06-11 15 11.1002/1000/10931 3.0 ITU-T G.657 2012-10-29 15 11.1002/1000/11769 4.0 ITU
16、-T G.657 2016-11-13 15 11.1002/1000/13078 Keywords Bending-loss insensitive optical fibre, dispersion un-shifted optical fibre, optical fibre and cable, single-mode optical fibre. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed
17、by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.657 (11/2016) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (I
18、CTs). 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 Telecommunicatio
19、n 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 areas of info
20、rmation 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 operating age
21、ncy. 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 “shall“ or som
22、e 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 RIGHTSITU draws attention to the possibility that the practice or i
23、mplementation 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 development pro
24、cess. 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 therefore strong
25、ly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2017 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.657 (11/2016) iii Table of Contents Page 1 Scope . 1 2 Referenc
26、es . 2 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this recommendation 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Fibre attributes 3 6.1 Mode field diameter . 3 6.2 Cladding diameter 3 6.3 Core concentricity error 3 6.4 Non-circularity . 3 6.5 Cut-off wavelength . 3 6.
27、6 Macrobending loss 4 6.7 Material properties of the fibre . 5 6.8 Refractive index profile 5 6.9 Longitudinal uniformity of chromatic dispersion . 5 6.10 Chromatic dispersion 5 7 Cable attributes . 6 7.1 Attenuation coefficient . 6 7.2 Polarization mode dispersion coefficient . 7 8 Recommended valu
28、e tables 7 Appendix I Lifetime expectation in the case of small radius bending of single-mode fibre . 12 Bibliography. 13 iv Rec. ITU-T G.657 (11/2016) Introduction Worldwide, technologies for broadband access networks and general transport networks are advancing rapidly. Among these, the technology
29、 applying single-mode fibre provides for a high-capacity transmission medium which can answer the growing demand for high speed networks. The experience with the installation and operation of single-mode fibre and cable-based networks is huge and Recommendation ITU-T G.652, which describes its chara
30、cteristics, has been adapted to this experience. Nevertheless, the specific use in an optical access network and some particular areas of general transport networks puts different demands on the fibre and cable. Due to dense distribution and drop-cable network, limited space and the many manipulatio
31、ns in parts of these networks, fibre and cable requirements may be optimized for improved macrobending loss. It is the aim of this Recommendation to support this optimization by recommending different attribute values for the existing ITU-T G.652 single-mode fibre and cables and by recommending othe
32、r categories of single-mode fibre types. As for the network structures in which the single-mode optical fibre cable is used, users are referred to the extensive information that is available in the references listed in the bibliography. Rec. ITU-T G.657 (11/2016) 1 Recommendation ITU-T G.657 Charact
33、eristics of a bending-loss insensitive single-mode optical fibre and cable 1 Scope This Recommendation describes two categories of single-mode optical fibre cable with improved bending loss performance compared with that of ITU-T G.652 fibres. ITU-T G.657 fibre was originally developed for use in ac
34、cess networks, including inside buildings at the end of these networks. Both categories A and B contain two subcategories which differ in macrobending loss. Category A fibres are optimized for reduced macrobending loss compared to ITU-T G.652.D fibres and can be deployed throughout the access networ
35、k. These fibres are suitable for use in the O-, E-, S-, C- and L-band (i.e., throughout the 1 260 nm to 1 625 nm range). Fibres and requirements in this category are a subset of ITU-T G.652.D and are therefore compliant1 with ITU-T G.652.D fibres and have the same transmission and interconnection pr
36、operties. Thus, ITU-T G.657.A fibres can be used for all networks where ITU-T G.652.D fibres are specified. Subcategory ITU-T G.657.A1 fibres are appropriate for a minimum design radius of 10 mm. Subcategory ITU-T G.657.A2 fibres are appropriate for a minimum design radius of 7.5 mm. Category B fibr
37、es are optimized for further reduced macrobending loss and therefore are capable of being used at very low values of bend radius. These fibres are intended for short reach distances (less than 1 000 m) at the end of access networks, in particular inside buildings or near buildings (e.g., outside bui
38、lding riser cabling). The application length of ITU-T G.657.B fibre depends on the deployment strategy of each network operator. These fibres are suitable for use in the O-, E-, S-, C- and L-band (i.e., throughout the 1 260 nm to 1 625 nm range). Category B fibres are not necessarily compliant with
39、ITU-T G.652.Din terms of chromatic dispersion coefficient and polarization mode dispersion (PMD) specifications. These fibres, however, are system compatible2 with ITU-T G.657.A (and ITU-T G.652.D) fibres in access networks. Subcategory ITU-T G.657.B2 fibres are appropriate for a minimum design radi
40、us of 7.5 mm. Subcategory ITU-T G.657.B3 fibres are appropriate for a minimum design radius of 5 mm. This Recommendation and the different performance categories found in Tables 1 and 2 in clause 8 are intended to support the following related system Recommendations: Category Recommendations Optical
41、 line systems for local and access networks b-ITU-T G.987.2, b-ITU-T G.989.2 The meaning of the terms used in this Recommendation and the guidelines to be followed in the measurement to verify the various characteristics are given in ITU-T G.650.1 and ITU-T G.650.2. _ 1 Compliance here means adheren
42、ce to the referenced Recommendation (ITU-T G.652, category D) meeting or exceeding the values of the specified attributes. 2 Compatibility means here that the product in this category will introduce negligible system impairment or deployment issues but may not be compliant with the referenced Recomm
43、endation (ITU-T G.652, category D). 2 Rec. ITU-T G.657 (11/2016) The characteristics of these fibre categories, including the definitions of the relevant parameters, their test methods and relevant values, will be refined as studies and experience progress. 2 References The following ITU-T Recommend
44、ations 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 valid. All Recommendations and other references are subject to revision; users of this Recommendation are theref
45、ore 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 Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-
46、alone document, the status of a Recommendation. ITU-T G.650.1 Recommendation ITU-T G.650.1 (2010), Definitions and test methods for linear, deterministic attributes of single-mode fibre and cable. ITU-T G.650.2 Recommendation ITU-T G.650.2 (2015), Definitions and test methods for statistical and non
47、-linear related attributes of single-mode fibre and cable. ITU-T G.652 Recommendation ITU-T G.652 (2016), Characteristics of a single-mode optical fibre and cable. ITU-T L.103 Recommendation ITU-T L.103 (2016), Optical fibre cables for indoor applications. IEC 60793-1-47 IEC 60793-1-47:2009, Optical
48、 fibres Part 1-47: Measurement methods and test procedures Macrobending loss. IEC 60793-2-50 IEC 60793-2-50:2015, Optical fibres Part 2-50: Product specifications Sectional specification for class B single-mode fibres. ISO 80000-1 ISO 80000-1 (2009), Quantities and units Part 1: General. 3 Definitio
49、ns 3.1 Terms defined elsewhere This Recommendation uses the terms defined in ITU-T G.650.1 and ITU-T G.650.2. 3.2 Terms defined in this recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: DGD Differential Group Delay PMD Polarization Mode Dispersion 5 Conventions Values shall be rounded to the number of digits given in the recommended values in Tables 1 and 2 before conformance is evaluated. The conven
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