1、 International Telecommunication Union ITU-T G.664TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Characteristics of optical components and subsystems Optical safet
2、y procedures and requirements for optical transmission systems Recommendation ITU-T G.664 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.679Characteristics 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 ASPECTS
6、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.664 (10/2012) i Recommendation IT
7、U-T G.664 Optical safety procedures and requirements for optical transmission systems Summary Recommendation ITU-T G.664 provides guidelines and requirements for techniques to enable optically safe working conditions (for the human eye and skin) on optical interfaces of the optical transport network
8、, in particular, for systems employing high-power Raman amplification techniques, for equipment in restricted and controlled locations. Due to revisions of relevant IEC requirements, the automatic laser shut-down (ALS) procedure, defined in a previous version of this Recommendation for synchronous d
9、igital hierarchy (SDH) systems, is no longer necessary and has therefore been moved to an informative appendix. Furthermore, this Recommendation provides new guidelines on automatic power reduction (APR) procedures for systems employing high-power Raman amplification techniques and this latest versi
10、on includes Raman-based GPON reach extension systems. History Edition Recommendation Approval Study Group 1.0 ITU-T G.664 1999-07-02 15 2.0 ITU-T G.664 2003-03-16 15 2.1 ITU-T G.664 (2003) Amd. 1 2005-01-13 15 3.0 ITU-T G.664 2006-03-29 15 4.0 ITU-T G.664 2012-02-13 15 5.0 ITU-T G.664 2012-10-29 15
11、ii Rec. ITU-T G.664 (10/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU.
12、 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 four years, establishes the topics for
13、 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, the necessary standards are prepared o
14、n 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. However, the Recommendation may cont
15、ain 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 negative equivalents are used to express
16、 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 use of a claimed Intellectual Propert
17、y 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, ITU had received notice of intell
18、ectual 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:/www.itu.int/ITU-T/ipr/. The author thanks
19、 the International Electrotechnical Commission (IEC) for permission to reproduce information from its International Publication IEC 60825-2 ed.3.2 (2010). All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved. Further information on the IEC is available from www.iec.ch. IE
20、C has no responsibility for the placement and context in which the extracts and contents are reproduced by the author, nor is IEC in any way responsible for the other content or accuracy therein. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, wi
21、thout the prior written permission of ITU. Rec. ITU-T G.664 (10/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acronyms 3 5 General considerations 4 5.1 Safety consi
22、derations for avoiding damage to the human eye and skin . 4 5.2 Considerations to keep fibres damage-free 6 6 Procedures and guidelines 6 6.1 General . 6 6.2 APR procedures for systems employing discrete optical amplification . 7 6.3 APR procedures for systems based upon distributed Raman amplificat
23、ion . 9 Appendix I Examples of automatic power reduction architectures for systems (including those based upon Raman amplification) deploying an optical auxiliary channel 12 I.1 Considerations on using an OAC instead of a restart pulse for automatic restart 12 I.2 Description of APR procedure using
24、co-propagating OSC 13 I.3 Description of APR procedure using counter-propagating OSC . 14 Appendix II Description of automatic laser shutdown/automatic power shut-down (ALS/APSD) procedures for single-channel point-to-point SDH systems 16 II.1 Introduction 16 II.2 Single-channel point-to-point SDH w
25、ithout line amplifiers 17 II.3 Single-channel point-to-point SDH with line amplifiers 20 Appendix III Example(s) of APR architecture for OAN systems based upon Raman amplification . 22 III.1 Further considerations on APR procedures in Raman amplified PON reach extenders . 22 Bibliography. 23 Rec. IT
26、U-T G.664 (10/2012) 1 Recommendation ITU-T G.664 Optical safety procedures and requirements for optical transmission systems 1 Scope This Recommendation provides guidelines and requirements for techniques to enable optically safe working conditions (for the human eye and skin) on optical interfaces
27、of optical networks, for both access and transport applications, including conventional synchronous digital hierarchy (SDH) systems, for equipment in both restricted and controlled locations. The actual definition and specification of optically safe levels are considered outside the scope of this Re
28、commendation (they are provided by IEC). The main fields of application are systems designed for the optical networks, both in access and transport applications, employing Raman amplification and dense wavelength division multiplexing (DWDM) systems with large channel counts. For the purpose of ease
29、 of operating these systems, this Recommendation focuses on automatic power reduction (APR) techniques with automatic restart. As backwards compatibility with earlier Recommendations on the subject of optical safety is desired, this Recommendation provides some descriptions for safety procedures in
30、the case of single and multichannel SDH systems with and without line amplifiers. Clarification is given as to why procedures employing restart pulses for automatic laser shut-down (ALS) and automatic power shut-down (APSD), defined in a previous version of this Recommendation, are no longer appropr
31、iate or necessary for applications given in ITU-T G.691, ITU-T G.693, ITU-T G.695, ITU-T G.957 and ITU-T G.959.1. The impact of bidirectional transmission as described in ITU-T G.692 has also been considered. Some references are provided for keeping fibres damage-free when being operated at high opt
32、ical power levels. 2 References The following ITU-T Recommendations 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
33、 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 below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a docu
34、ment within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.662 Recommendation ITU-T G.662 (2005), Generic characteristics of optical amplifier devices and subsystems. ITU-T G.665 Recommendation ITU-T G.665 (2005), Generic characteristics of R
35、aman amplifiers and Raman amplified subsystems. ITU-T G.691 Recommendation ITU-T G.691 (2006), Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers. ITU-T G.692 Recommendation ITU-T G.692 (1998), Optical interfaces for multichannel systems with optical amplifier
36、s. ITU-T G.693 Recommendation ITU-T G.693 (2009), Optical interfaces for intra-office systems. 2 Rec. ITU-T G.664 (10/2012) ITU-T G.695 Recommendation ITU-T G.695 (2010), Optical interfaces for coarse wavelength division multiplexing applications. ITU-T G.698.1 Recommendation ITU-T G.698.1 (2009), M
37、ultichannel DWDM applications with single channel optical interfaces. ITU-T G.698.2 Recommendation ITU-T G.698.2 (2009), Amplified multichannel dense wavelength division multiplexing applications with single channel optical interfaces. ITU-T G.783 Recommendation ITU-T G.783 (2006), Characteristics o
38、f synchronous digital hierarchy (SDH) equipment functional blocks. ITU-T G.798 Recommendation ITU-T G.798 (2010), Characteristics of optical transport network hierarchy equipment functional blocks. ITU-T G.872 Recommendation ITU-T G.872 (2001), Architecture of optical transport networks. ITU-T G.957
39、 Recommendation ITU-T G.957 (2006), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. ITU-T G.959.1 Recommendation ITU-T G.959.1 (2009), Optical transport network physical layer interfaces. ITU-T G.983.x Recommendation ITU-T G.983.x series, Broadband optica
40、l access systems based on Passive Optical Networks (PON). ITU-T G.984.x Recommendation ITU-T G.984.x series, Gigabit-capable passive optical networks (GPON). ITU-T G.984.6 Recommendation ITU-T G.984.6 (2008), Gigabit-capable passive optical networks (GPON): Reach extension. ITU-T G.985 Recommendatio
41、n ITU-T G.985 (2003), 100 Mbit/s point-to-point Ethernet based optical access system. ITU-T G.986 Recommendation ITU-T G.986 (2010), 1 Gbit/s point-to-point Ethernet-based optical access system. ITU-T G.987.x Recommendation ITU-T G.987.x series, 10-Gigabit-capable passive optical network (XG-PON) sy
42、stems. IEC 60825-1 IEC 60825-1 edition 2.0 (2007), Safety of laser products Part 1: Equipment classification and requirements. IEC 60825-2 IEC 60825-2 edition 3.2 (2010), Safety of laser products Part 2: Safety of optical fibre communication systems (OFCS). IEC/TR 61292-4 IEC/TR 61292-4 edition 2.0
43、(2010), Optical amplifiers Part 4: Maximum permissible optical power for the damage-free and safe use of optical amplifiers, including Raman amplifiers. 3 Terms and definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 controlled locations: IEC
44、 60825-2. 3.1.2 hazard level: IEC 60825-2. Rec. ITU-T G.664 (10/2012) 3 3.1.3 laser class: IEC 60825-1. 3.1.4 Loss of Signal (LOS): ITU-T G.783. 3.1.5 LOS overhead (LOS-O): ITU-T G.798. 3.1.6 LOS payload (LOS-P): ITU-T G.798. 3.1.7 optical multiplex section (OMS): ITU-T G.872. 3.1.8 optical supervis
45、ory channel (OSC): ITU-T G.692. 3.1.9 optical transmission section (OTS): ITU-T G.872. 3.1.10 restricted locations: IEC 60825-2. 3.1.11 unrestricted locations: IEC 60825-2. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 automatic laser shut-down (ALS)
46、: A technique (procedure) to automatically shut down the output power of laser transmitters and optical amplifiers to avoid exposure to hazardous levels. 3.2.2 automatic power reduction (APR): A technique (procedure) to automatically reduce the output power of optical amplifiers to avoid exposure to
47、 hazardous levels. 3.2.3 automatic power shut-down (APSD): A technique (procedure) to automatically shut down the output power of optical amplifiers to avoid exposure to hazardous levels; within the context of this Recommendation, the term APSD is equivalent to the term ALS. 3.2.4 loss of continuity
48、 (of an optical link): Any event which may cause hazardous optical power levels to be emitted from some point along the path of an optical transmission system. Common causes of loss of continuity of an optical link are a cable break, equipment failure, connector unplugging, etc. 3.2.5 main (optical)
49、 path: The fibre plant between the source main path interface reference point (MPI-S), S or S point of the transmitting equipment and the receive main path interface reference point (MPI-R), R or R point of the receiving equipment. 3.2.6 main path interfaces: The interfaces to the fibre plant. 3.2.7 optical auxiliary channel (OAC): An optical signal that fails in the event of loss of fibre continuity but does not require hazardous power levels to operate satis
