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 L.93 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2014) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Optical fibre cable maintenance support, monitoring and testin
2、g systems for optical fibre trunk networks Recommendation ITU-T L.93 Rec. ITU-T L.93 (05/2014) i Recommendation ITU-T L.93 Optical fibre cable maintenance support, monitoring and testing systems for optical fibre trunk networks Summary Recommendation ITU-T L.93 describes requirements for optical fib
3、re cable maintenance support, monitoring and testing systems for optical fibre trunk networks. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L.93 2014-05-14 15 11.1002/1000/12199 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of y
4、our web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T L.93 (05/2014) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and comm
5、unication 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. T
6、he 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
7、 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
8、 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.
9、 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 RIGHTSITU draws attention to the possibili
10、ty 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 Recom
11、mendation 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
12、 and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2014 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 L.93 (05/2014) iii Table of Contents Pag
13、e 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Fundamental requirements 3 7 Specific requirements for optical trunk lines 3 7.1 Applicable area . 4 7.2 Test access devices . 4
14、7.3 Requirements for in-service monitoring . 5 8 Test methods . 5 8.1 Methods for testing the characteristics of optical fibre cable networks . 5 8.2 Test methods for verifying service contracts or transmission at particular bit rates . 5 9 Testing and maintenance procedure . 6 9.1 Confirmation of f
15、ibre condition 6 9.2 Fault identification between transmission equipment and fibre network . 6 Appendix I Japans experience 7 I.1 Introduction 7 I.2 System configuration 7 I.3 Test access module . 8 Bibliography. 10 iv Rec. ITU-T L.93 (05/2014) Introduction Trunk line communication traffic is increa
16、sing rapidly. An optical fibre line testing system is essential for reducing maintenance costs and improving service reliability in optical fibre networks. Some technologies that are used in trunk lines (e.g., wavelength division multiplexing (WDM) systems and erbium doped fibre amplifier (EDFA) req
17、uire additional functions and procedures for optical fibre line testing systems. The system requirements described in this Recommendation help to achieve reliable maintenance of optical cables for trunk lines. Rec. ITU-T L.93 (05/2014) 1 Recommendation ITU-T L.93 Optical fibre cable maintenance supp
18、ort, monitoring and testing systems for optical fibre trunk networks 1 Scope This Recommendation addresses optical fibre maintenance support, monitoring and testing systems for trunk optical fibre cable networks. It describes fundamental requirements, functions and test procedures for use in mainten
19、ance operations. It applies to the test equipment and methods, configuration and optical devices, such as test access devices for connecting the test equipment to the communication line, which are components of the maintenance system. The aspects related to active monitoring to detect communication
20、signal degradation and the status of the transmission equipment are described in ITU-T G.697. The functional architecture and parameters specialized for submarine applications are described in ITU-T G.979. 2 References The following ITU-T Recommendations and other references contain provisions which
21、, 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 therefore encouraged to investigate the possibility of app
22、lying 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-alone document, the status of a Recommendation. ITU-
23、T G.650.3 Recommendation ITU-T G.650.3 (2008), Test methods for installed single-mode optical fibre cable links. ITU-T G.652 Recommendation ITU-T G.652 (2009), Characteristics of a single-mode optical fibre and cable. ITU-T G.653 Recommendation ITU-T G.653 (2010), Characteristics of a dispersion-shi
24、fted, single-mode optical fibre and cable. ITU-T G.654 Recommendation ITU-T G.654 (2012), Characteristics of a cut-off shifted, single-mode optical fibre and cable. ITU-T G.655 Recommendation ITU-T G.655 (2009), Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable. IT
25、U-T G.656 Recommendation ITU-T G.656 (2010), Characteristics of a fibre and cable with non-zero dispersion for wideband optical transport. ITU-T G.664 Recommendation ITU-T G.664 (2012), Optical safety procedures and requirements for optical transmission systems. ITU-T G.697 Recommendation ITU-T G.69
26、7 (2012), Optical monitoring for dense wavelength division multiplexing systems. ITU-T G.979 Recommendation ITU-T G.979 (2012), Characteristics of monitoring systems for optical submarine cable systems. ITU-T L.25 Recommendation ITU-T L.25 (1996), Optical fibre cable network maintenance. ITU-T L.40
27、Recommendation ITU-T L.40 (2000), Optical fibre outside plant maintenance support, monitoring and testing system. 2 Rec. ITU-T L.93 (05/2014) ITU-T L.41 Recommendation ITU-T L.41 (2000), Maintenance wavelength on fibres carrying signals. ITU-T L.50 Recommendation ITU-T L.50 (2010), Requirements for
28、passive optical nodes: Optical distribution frames for central office environments. ITU-T L.66 Recommendation ITU-T L.66 (2007), Optical fibre cable maintenance criteria for in-service fibre testing in access networks. ITU-T L.68 Recommendation ITU-T L.68 (2007), Optical fibre cable maintenance supp
29、ort, monitoring and testing system for optical fibre cable networks carrying high total optical power. ITU-T L.85 Recommendation ITU-T L.85 (2010), Optical fibre identification for the maintenance of optical access networks. IEC 60825-1 IEC 60825-1 ed3.0 (2014), Safety of laser products Part 1: Equi
30、pment classification and requirements. IEC 60825-2 IEC 60825-2 ed3.2 (2010), Safety of laser products Part 2: Safety of optical fibre communication systems (OFCS). IEC 61280-4-2 IEC 61280-4-2 ed2.0 (2014), Fibre-optic communication subsystem test procedures Part 4-2: Installed cable plant Single-mod
31、e attenuation and optical return loss measurement. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 attenuation of an optical fibre cable link ITU-T G.650.3. 3.1.2 fibre characterization ITU-T G.650.3. 3.1.3 optical distribution frame (O
32、DF) ITU-T L.50. 3.2 Terms defined in this Recommendation This Recommendation defines the following term: 3.2.1 optical trunk line: A part of the optical fibre cable network that is located between two central offices. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations
33、and acronyms: CWDM Coarse Wavelength Division Multiplexing DCN Data Communication Network DWDM Dense Wavelength Division Multiplexing EDFA Erbium Doped Fibre Amplifier FBG Fibre Bragg Grating FS Fibre Selector FTTx Fibre to the x, where “x“ indicates the final location on the user side of any one of
34、 a variety of optical fibre architectures, e.g., FTTB, FTTC, FTTH, FTTP. Rec. ITU-T L.93 (05/2014) 3 IDM Integrated Distribution Module ODF Optical Distribution Frame OPM Optical Power Meter OTDR Optical Time Domain Reflectometer OTM Optical Testing Module PLC Planar Lightwave Circuit PMD Polarizati
35、on Mode Dispersion TAM Test Access Module WDM Wavelength Division Multiplexing 5 Conventions None. 6 Fundamental requirements Data communication traffic in both, access networks and optical trunk lines, is rapidly increasing. Therefore, the optical fibre cable for trunk lines is becoming increasingl
36、y important because of its large transmission capacity. The fundamental requirements for optical fibre cable maintenance support, monitoring and testing systems for optical trunk lines are as follows: An optical fibre cable maintenance support, monitoring and testing system must perform efficiently
37、the maintenance work described in ITU-T L.25. An optical fibre cable maintenance support, monitoring and testing system should provide the surveillance, testing and control functions listed in ITU-T L.40 to meet the system specifications for optical fibres or fibre-optic components even when applied
38、 to optical trunk lines. It must be safe for network operators to handle the optical fibre cables, cords and fibre-optic components of the optical fibre cable maintenance support, monitoring and testing system. Network operator safety must be in accordance with ITU-T G.664, IEC 60825-1 and IEC 60825
39、-2. 7 Specific requirements for optical trunk lines Figure 1 shows a typical configuration of an optical trunk line as defined in clause 3. There are some additional requirements for an optical fibre line testing system for optical trunk line cable networks. In general, an optical trunk line has a l
40、ong transmission distance and must have a low attenuation. Therefore, the fibre-optic devices that are inserted in the communication lines for testing must also have a low insertion loss. In addition, test equipment must provide highly accurate measurements because of the importance of the optical t
41、runk line. Specific requirements and functions for trunk lines are described below. 4 Rec. ITU-T L.93 (05/2014) L . 9 3 (1 4 )_ F 0 1ODF ODFODFCe n t ra lo ff i ceCe n t ra lo ff i ceCe n t ra lo ff i ce A er i al fa ci l i t i esU n d er g ro u n d fa ci l i t i esO p t i ca l t ru n k l i n e O p
42、t i ca l t ru n k l i n eU n d er g ro u n d fa ci l i t i esFigure 1 Typical configuration of an optical trunk line 7.1 Applicable area The applicable area of the optical fibre cable maintenance support, monitoring and testing systems is optical trunk lines. The characteristics of the optical fibre
43、s in this area should comply with ITU-T G.652, ITU-T G.653, ITU-T G.654, ITU-T G.655 and ITU-T G.656. 7.2 Test access devices There are several ways to implement the maintenance functions described in ITU-T L.40: Optical time domain reflectometer (OTDR) testing for optical fibre cable; optical loss
44、testing, identification light detection and optical power monitoring of optical signals by using an optical power meter (OPM). Therefore, optical fibre cable maintenance systems should have optical branching devices for test light insertion (e.g., an optical coupler). The branching device for test u
45、se should have a low insertion loss in both the communication and test ports. Therefore, wavelength selective couplers or wavelength division multiplexing (WDM) couplers would appear to be efficient devices for testing. Also, the optical branching device should have a wide wavelength range for commu
46、nication signals when the optical trunk lines accommodate services using WDM transmission systems. The operating wavelength range in terms of spectral bands is described in b-ITU-T G.Sup39. If applications using the L-band (1565-1625 nm) are likely to be used in the future, it is recommended that th
47、e test access device also has a transmission range up to 1625 nm for the communication port. When the length of an optical trunk line cable exceeds the measurable range of the test equipment, branching devices must be inserted at both ends of the optical trunk line for bidirectional testing. (See cl
48、ause 8.1.1) A typical configuration of the optical trunk line with test access devices is shown in Figure 2. L . 9 3 (1 4 )_ F 0 2ODFT ran s m i s s i o neq u i p m en tT es tequ i pm entT es t a cces sdev i ceC en t ral o ff i ceO p t i cal t ru n k l i n eODFT ran s m i s s i o neq u i p m en tT e
49、s tequ i pm entT es t a cces sdev i ceC en t ral o ff i ceFigure 2 Typical configuration of an optical trunk line with test access devices Rec. ITU-T L.93 (05/2014) 5 7.3 Requirements for in-service monitoring 7.3.1 In-service monitoring ITU-T L.66 defines several requirements for in-service monitoring such as the wavelength bandwidth and optical power level of the test light, and the characteristics of the test light cut-off filter and measurement equipment. Th
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