1、 International Telecommunication Union ITU-T G.661TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2007) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media and optical systems characteristics Characteristics of optical components and subsystems Definitions a
2、nd test methods for the relevant generic parameters of optical amplifier devices and subsystems ITU-T Recommendation G.661 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS C
3、OMMON TO ALL ANALOGUE CARRIER-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 LINE
4、S 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 G.610G.619 Land coaxial cable pairs G.620G.629 Submarine cables G.630G.639 Free space optical systems G.640G.649 Optica
5、l 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 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AN
6、D 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 NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.661 (07/200
7、7) i ITU-T Recommendation G.661 Definitions and test methods for the relevant generic parameters of optical amplifier devices and subsystems Summary ITU-T Recommendation G.661 provides the definitions of the relevant parameters, common to the different types of optical amplifiers and the test method
8、s of said parameters to be followed, as far as applicable, for optical amplifier devices and subsystems covered by ITU-T Recommendations. Source ITU-T Recommendation G.661 was approved on 29 July 2007 by ITU-T Study Group 15 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.6
9、61 (07/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff q
10、uestions 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 study by the ITU-T study groups which, in turn, produce Recommendat
11、ions 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 on a collaborative basis with ISO and IEC. NOTE In this Recommendatio
12、n, 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 contain certain mandatory provisions (to ensure e.g. interoperability or
13、 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 requirements. The use of such words does not suggest that compliance
14、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 Property Right. ITU takes no position concerning the evidence, validity or ap
15、plicability 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 intellectual property, protected by patents, which may be required to implem
16、ent 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/. ITU 2008 All rights reserved. No part of this publication may be reproduced, by any mea
17、ns whatsoever, without the prior written permission of ITU. ITU-T Rec. G.661 (07/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Abbreviations and acronyms 1 4 Classification 2 5 Definitions 3 5.1 Definitions for OA devices and ONEs containing OAs. 6 5.2 Parameters for OA subsystems. 15 6 Test m
18、ethods. 16 Appendix I Main differences between optical fibre amplifiers and semiconductor optical amplifiers 18 I.1 General remarks 18 I.2 Comparison of optical performance characteristics between SOA and OFA 19 I.3 Applications 20 Appendix II Environmental, mechanical, physical and reliability para
19、meters of optical amplifier devices and subsystems. 21 II.1 Parameters for OA devices. 21 II.2 Parameters for OA subsystems. 22 II.3 Environmental and reliability test methods 23 Bibliography. 24 ITU-T Rec. G.661 (07/2007) 1 ITU-T Recommendation G.661 Definitions and test methods for the relevant ge
20、neric parameters of optical amplifier devices and subsystems 1 Scope This Recommendation applies to all commercially available optical amplifiers (OAs), optically amplified subsystems and optical network elements (ONEs) containing OAs. It applies to OAs using optically pumped fibres (OFAs based eith
21、er on rare-earth doped fibres or on the Raman effect), semiconductors (SOAs) and waveguides (POWAs). This Recommendation provides the definitions of the relevant parameters, common to the different types of OAs, listed in clause 5, and the test methods of said parameters described in clause 6, to be
22、 followed, as far as applicable, for OA devices and subsystems covered by ITU-T Recommendations. Parameter definitions applicable specifically to distributed Raman amplifiers, however, can be found in ITU-T G.665. 2 References The following ITU-T Recommendations and other references contain provisio
23、ns 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 therefore encouraged to investigate the possibilit
24、y 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-alone document, the status of a Recommendati
25、on. ITU-T G.662 ITU-T Recommendation G.662 (2005), Generic characteristics of optical amplifier devices and subsystems. ITU-T G.663 ITU-T Recommendation G.663 (2000), Application related aspects of optical amplifier devices and subsystems. ITU-T G.665 ITU-T Recommendation G.665 (2005), Generic chara
26、cteristics of Raman amplifiers and Raman amplified subsystems. ITU-T G.680 ITU-T Recommendation G.680 (2007), Physical transfer functions of optical network elements. IEC 61290 IEC 61290 (all parts), Basic specification for optical amplifier test methods. IEC 61291-1 IEC 61291-1 (2006), Optical ampl
27、ifiers Part 1: Generic specification. Parameters specified for OAs are those characterizing the transmission, operation, reliability and environmental properties of the OA seen as a “black box“ from a general point of view. In ITU-T G.662, a subset of these parameters is specified according to the t
28、ype and application of the particular OA device or subsystem. 3 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ASE Amplified Spontaneous Emission BER Bit Error Ratio Bsp-sp Spontaneous-spontaneous optical bandwidth 2 ITU-T Rec. G.661 (07/2007) DGD Diffe
29、rential Group Delay DOP Degree of Polarization EDFA Erbium-Doped (silica-based) Fibre Amplifier F noise Factor FIT Failures In Time FWHM Full-Width Half-Maximum MPI Multi-Path Interference MTBF Mean Time Between Failures NF Noise Figure OA Optical Amplifier OAR Optically Amplified Receiver OAT Optic
30、ally Amplified Transmitter OFA Optical Fibre Amplifier ONE Optical Network Element OSA Optical Spectrum Analyser PDG Polarization Dependent Gain PDL Polarization Dependent Loss PMD Polarization Mode Dispersion POWA Planar Optical Waveguide Amplifier PSP Principal State of Polarization SNR Signal-to-
31、Noise Ratio SOA Semiconductor Optical Amplifier SOP State Of Polarization TM Test Method 4 Classification Different OA application categories are defined depending on the technology used and the utilization of the OA itself. Classification of optical amplifier technologies is also given in IEC/TR 61
32、292-3. These categories are identified by a capital letter, a number and a lower case letter, as follows: Capital letter A OFAs using silica-based fibres doped with erbium ions to produce an active fibre B OFAs using other doped active fibres C Raman amplifiers D SOA E POWA ITU-T Rec. G.661 (07/2007
33、) 3 Number 1 Power amplifiers (post-amplifiers or booster amplifiers) 2 Pre-amplifiers 3 Line amplifiers 4 Optically amplified transmitter (OAT) 5 Optically amplified receiver (OAR) 6 Distributed amplifiers 7 Composite distributed and discrete amplifiers Lower case letter a Amplifiers for analogue,
34、single (wavelength) channel transmission b Amplifiers for digital, single (wavelength) channel transmission c Amplifiers for digital, multichannel (wavelength) transmission EXAMPLE Category A2b refers to optical pre-amplifiers for single-channel digital transmission which use a silica-based fibre do
35、ped with Erbium ions. The power amplifier is a high saturation-power OA device to be used directly after the optical transmitter to increase its signal power level. The pre-amplifier is a very low noise OA device to be used directly before an optical receiver to improve its sensitivity. The line amp
36、lifier is a low noise OA device to be used between passive fibre sections to increase the distance covered before regeneration is necessary or in correspondence with a point-multipoint connection to compensate for branching losses in the optical access network. The OAT is an OA subsystem in which a
37、power amplifier is integrated with an optical transmitter, resulting in a higher power transmitter. The OAR is an OA subsystem in which a pre-amplifier is integrated with an optical receiver, resulting in a higher sensitivity receiver. The distributed amplifier is a device configuration that provide
38、s amplification over an extended length of the optical fibre used for transmission, as by Raman pumping, and is thus distributed over part or all of the transmission span. The composite distributed and discrete amplifiers are defined in ITU-T G.665. 5 Definitions The list of parameter definitions of
39、 OAs, given in the following part of this clause, is divided into two parts: the first part lists those parameters relevant for OA devices, namely power, pre-, line-, distributed amplifiers and ONEs containing OAs; the second part lists the parameters relevant for optically amplified, elementary sub
40、systems, namely the optically amplified transmitter (OAT) and the optically amplified receiver (OAR). Where the value of a parameter is given for a particular device, it will be necessary to specify certain appropriate operating conditions such as temperature, bias current, pump optical power, etc.
41、In this clause, two different operating conditions are referred to: nominal operating conditions, which are those suggested by the manufacturer for normal use of the OA, and limiting operating conditions, in which all the parameters adjustable by the user (e.g., temperature, gain, pump laser injecti
42、on current, etc.) are at their maximum values, according to the absolute maximum ratings stated by the manufacturer. 4 ITU-T Rec. G.661 (07/2007) The OA is considered as a “black box“, as shown in Figure 1. The OA device has two optical ports, namely an input and an output port. The ONE, as shown in
43、 Figure 2, contains one or more OAs, which can be located at the input as well as at the output. The location and number of OAs depends on their function in the ONE. Some ONE examples are described in ITU-T G.680. Each ONE has, at a minimum, one input and one output. The ONE is considered as a “blac
44、k box“. The OAT and OAR are considered as an OA integrated with a transmitter or a receiver, respectively. Both kinds of integration imply that the connection between the transmitter or the receiver and the OA is proprietary and not to be specified. Consequently, only the optical output port can be
45、defined for the OAT (after the OA, as shown in Figure 3) and only the optical input port can be defined for the OAR (before the OA, as shown in Figure 4). The optical ports may consist of unterminated fibres or optical connectors. Electrical connections for power supply (not shown in Figures 1 to 4)
46、 are also necessary. Following this “black box“ approach, the loss of both pairs of connectors directly associated with the device (labelled C or C in Figures 1 to 4) and the corresponding uncertainty will be included within the values of gain, noise figure and other parameters of the OA device. Fig
47、ure 1 OA device reference diagram Figure 2 ONE device reference diagram Figure 3 OAT reference diagram ITU-T Rec. G.661 (07/2007) 5 Figure 4 OAR reference diagram It should be noted that the configurations in Figures 1 to 4 are shown in the context of ITU-T reference points. It indicates the loss of
48、 two connector pairs are included in the black box OA or ONE rather than one. ITU-T reference planes normally account for connector losses differently, as indicated in ITU-T G.662. More complete treatment of this topic can be found in Appendix III of ITU-T G.665. The user is advised to take the appr
49、opriate loss differences into consideration. The OA amplifies signals in a nominal operating wavelength region. In addition, other signals outside of the band of operating wavelength can in some applications also cross the OA. The purpose of these out-of-band signals and their wavelength, or wavelength region, can be specified in the detailed specifications. When signals at multiple wavelengths are incident on the OA, as is the case in multichannel systems, suitable adjustment of the definitions of some existing relevant
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