1、 International Telecommunication Union ITU-T G.651.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2007) 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 multimode gra
2、ded index optical fibre cable for the optical access network ITU-T Recommendation G.651.1 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-TRA
3、NSMISSION 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 RADI
4、OTELEPHONY 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 Charact
5、eristics 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 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.19
6、99 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.651.1 (07/2007) i ITU-T Recommendation G.651
7、.1 Characteristics of a 50/125 m multimode graded index optical fibre cable for the optical access network Summary ITU-T Recommendation G.651.1 recommends a quartz multimode fibre to be used for the access network in specific environments. These environments are multi-tenant building sub-networks in
8、 which broadband services have to be delivered to individual apartments. The recommended multimode fibre supports the cost-effective use of 1 Gbit/s Ethernet systems over link lengths up to 550 m, usually based upon the use of 850 nm transceivers. The recommended fibre type is an improved version of
9、 the well-known 50/125 m multimode graded-index fibre as recommended in ITU-T Recommendation G.651. Its cost effective use is very common in datacom systems applied in enterprise buildings throughout the world for quite a number of years. Source ITU-T Recommendation G.651.1 was approved on 29 July 2
10、007 by ITU-T Study Group 15 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.651.1 (07/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector
11、 (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 Telecommunication Standardization Assembly (WTSA), which meets every f
12、our 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 information technology which fall within ITU-Ts purview, t
13、he 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 agency. Compliance with this Recommendation is voluntary.
14、 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 some other obligatory language such as “must“ and the negat
15、ive 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 that the practice or implementation of this Recommendation may involve the us
16、e 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 process. As of the date of approval of this Recommendation
17、, 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 strongly urged to consult the TSB patent database at http:/ww
18、w.itu.int/ITU-T/ipr/. ITU 2008 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.651.1 (07/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 4 Abbreviations and acronyms 2
19、 5 Fibre attributes 2 5.1 Cladding diameter 3 5.2 Core diameter . 3 5.3 Core concentricity error 3 5.4 Non-circularity . 3 5.5 Numerical aperture . 3 5.6 Macrobending loss 3 5.7 Material properties of the fibre. 4 5.8 Refractive index profile 4 5.9 Modal bandwidth 4 5.10 Chromatic dispersion coeffic
20、ient 4 6 Cable attributes . 5 6.1 Attenuation coefficient . 5 6.2 Modal bandwidth 5 7 Tables of recommended values 5 Bibliography. 7 iv ITU-T Rec. G.651.1 (07/2007) Introduction Worldwide, various technologies for broadband access networks are advancing rapidly to provide the high capacity needed fo
21、r the increasing customer demands with respect to new services. Apart from the technologies, also the network structures and customer densities vary considerably. A specific segment, which is in the main scope of this Recommendation, is the network in a multi-tenant building. Quite a large percentag
22、e of all customers in the world are living in these buildings. Due to the high connection density and the short distribution cable lengths, cost-effective high capacity optical networks can be designed and installed by making use of 50/125 m graded-index multimode fibres. The effective use of this n
23、etwork type has been shown by its extended and experienced use for datacom systems in enterprise buildings with system bit rates ranging from 10 Mbit/s up to 10 Gbit/s. This use is supported by a large series of IEEE system standards and IEC fibre and cable standards which are used as the main refer
24、ences in this Recommendation. ITU-T Rec. G.651.1 (07/2007) 1 ITU-T Recommendation G.651.1 Characteristics of a 50/125 m multimode graded index optical fibre cable for the optical access network 1 Scope This Recommendation describes a 50/125 m graded-index multimode optical fibre cable which is suita
25、ble to be used in the 850 nm or 1300 nm region, or alternatively may be used in both wavelength regions simultaneously. The geometrical, optical, transmission and mechanical parameters are described below in two categories of attributes: fibre attributes are those attributes that are retained throug
26、hout cabling and installation; cable attributes that are recommended for cables as they are delivered. This Recommendation, and the different performance categories found in Table 1, is intended to support the following related system Recommendations and standards: b-IEEE 802.3. The characteristics
27、of this fibre, 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 Recommendations and other references contain provisions which, through reference in this text, constitute
28、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 of the Recommen
29、dations 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. IEC 60793-1-1 IEC 60793-1-1 (2002), Optical fibre
30、s Part 1-1: Measurement methods and test procedures General and guidance. IEC 60793-1-20 IEC 60793-1-20 (2001), Optical fibres Part 1-20: Measurement methods and test procedures Fibre geometry. IEC 60793-1-30 IEC 60793-1-30 (2001), Optical fibres Part 1-30: Measurement methods and test procedures Fi
31、bre proof test. IEC 60793-1-40 IEC 60793-1-40 (2001), Optical fibres Part 1-40: Measurement methods and test procedures Attenuation. IEC 60793-1-41 IEC 60793-1-41 (2003), Optical fibres Part 1-41: Measurement methods and test procedures Bandwidth. IEC 60793-1-42 IEC 60793-1-42 (2007), Optical fibres
32、 Part 1-42: Measurement methods and test procedures Chromatic dispersion. IEC 60793-1-43 IEC 60793-1-43 (2001), Optical fibres Part 1-43: Measurement methods and test procedures Numerical aperture. IEC 60793-1-47 IEC 60793-1-47 (2006), Optical fibres Part 1-47: Measurement methods and test procedure
33、s Macrobending loss. 2 ITU-T Rec. G.651.1 (07/2007) IEC 60793-1-49 IEC 60793-1-49 (2006), Optical fibres Part 1-49: Measurement methods and test procedures Differential mode delay. IEC 60793-2 IEC 60793-2 (2003), Optical fibres Part 2: Product specifications General. IEC 60793-2-10 IEC 60793-2-10 (2
34、007), Optical fibres Part 2-10: Product specifications Sectional specification for category A1 multimode fibres. IEC 60794-2 IEC 60794-2 (2002), Optical fibre cables Part 2: Indoor cables Sectional specification. IEC 60794-2-11 IEC 60794-2-11 (2002), Optical fibre cables Part 2-11: Indoor cables Det
35、ailed specification for simplex and duplex cables for use in premises cabling. IEC 60794-2-21 IEC 60794-2-21 (2005), Optical fibre cables Part 2-21: Indoor cables Detailed specification for multi-fibre optical distribution cables for use in premises cabling. IEC 60794-2-31 IEC 60794-2-31 (2005), Opt
36、ical fibre cables Part 2-31: Indoor cables Detailed specification for optical fibre ribbon cables for use in premises cabling. IEC 60794-3-12 IEC 60794-3-12 (2005), Optical fibre cables Part 3-12: Outdoor cables Detailed specification for duct and directly buried optical telecommunication cables for
37、 use in premises cabling. IEC 61280-4-1 IEC 61280-4-1 (2003), Fibre-optic communication subsystem test procedures Part 4-1: Cable plant and links Multimode fibre-optic cable plant attenuation measurement. 3 Terms and definitions For the purposes of this Recommendation, the definitions and the guidel
38、ines to be followed in the measurement to verify the various characteristics are given in the IEC standards series IEC 60793, IEC 60794 and IEC 61280-4-1. Values shall be rounded to the number of digits given in Table 1 before conformance is evaluated. 4 Abbreviations and acronyms This Recommendatio
39、n uses the following abbreviation: NA Numerical Aperture 5 Fibre attributes The characteristics of the fibre providing a minimum essential design framework for fibre manufacture, system design and use are recommended in this clause and in clause 7. Ranges or limits on values are presented in Table 1
40、. In this clause those attributes have been listed only where additional information is helpful. The recommended characteristics will not be significantly affected by cable manufacture or installation and therefore apply equally to individual fibres, fibres incorporated into a cable wound on a drum,
41、 and fibres in an installed cable. ITU-T Rec. G.651.1 (07/2007) 3 5.1 Cladding diameter The recommended nominal value of the cladding diameter is 125 m. A tolerance is also specified and shall not exceed the value in clause 7. The cladding diameter deviation from nominal shall not exceed the specifi
42、ed tolerance. For measuring the value of this attribute, reference is made to IEC 60793-1-20. 5.2 Core diameter The recommended nominal value of the core diameter is 50 m. A tolerance is also specified and shall not exceed the value in clause 7. The core diameter deviation from nominal shall not exc
43、eed the specified tolerance. For measuring the value of this attribute, reference is made to IEC 60793-1-20. 5.3 Core concentricity error The core concentricity error shall not exceed the value specified in clause 7. For measuring the value of this attribute, reference is made to IEC 60793-1-20. 5.4
44、 Non-circularity 5.4.1 Cladding non-circularity The cladding non-circularity shall not exceed the value found in clause 7. For measuring the value of this attribute, reference is made to IEC 60793-1-20. 5.4.2 Core non-circularity The core non-circularity shall not exceed the value found in clause 7.
45、 For measuring the value of this attribute, reference is made to IEC 60793-1-20. 5.5 Numerical aperture The numerical aperture (NA) is the sine of the vertex half-angle of the largest cone of rays that can enter or leave the core of an optical fibre, multiplied by the refractive index of the medium
46、in which the vertex of the cone is located. All values measured at 850 nm. The value of the numerical aperture is about 5% lower than the value of the maximum theoretical numerical aperture (NAtmax) which is derived from a refractive index measurements trace of the core and cladding. ()2221maxnnNAt=
47、 in which n1 is the maximum refractive index of the core and n2 is the refractive index of the innermost homogeneous cladding. For measuring the value of this attribute, reference is made to IEC 60793-1-43. 5.6 Macrobending loss Macrobending loss varies with bend radius and number of turns about a m
48、andrel with a specified radius but is rather independent of the measuring wavelength. Therefore, testing at one of the wavelengths specified in clause 7 may be sufficient to ensure compliance with this Recommendation. When testing multiple macrobends, the mode distribution encountered at a specific
49、macrobend may depend on how many macrobends precede it. For example, the first bend might influence the launch condition at the second bend, and the second bend might influence the launch condition at the third bend, etc. Consequently, the macrobending-added loss at a given bend might be different than the macrobending-added loss at another bend. In particular, the first bend may have the largest influence on following bends. Conseq
