1、 International Telecommunication Union ITU-T G.662TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2005) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Transmission media characteristics Characteristics of optical components and subsystems Generic characteristics of optica
2、l amplifier devices and subsystems ITU-T Recommendation G.662 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-TRANSMISSION SYSTEMS G.200G.299
3、 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 RADIOTELEPHONY AND LINE TELEPHON
4、Y G.450G.499 TRANSMISSION MEDIA 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.649 Optical fibre cables G.650G.659 Characteristics of optical components and subsystems G.660G.699 DIGITAL TERMINAL EQUIPMENTS G
5、.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.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 ETHERNET OVER TRANSPORT ASPECTS
6、G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.662 (07/2005) i ITU-T Recommendation G.662 Generic characteristics of optical amplifier devices and subsystems Summary The purpose of this Recommendation is to provide the g
7、eneric characteristics needed for the specification of Optical Amplifiers as devices and subsystems, primarily for applications in digital transmission, and to ensure maximum compatibility with ITU-T G-series Recommendations relating to line systems and equipments. Source ITU-T Recommendation G.662
8、was approved on 14 July 2005 by ITU-T Study Group 15 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.662 (07/2005) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication
9、 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 Telecommunication Standardization Assembly (WTS
10、A), 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 information technology which fall w
11、ithin 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 agency. Compliance with this Recom
12、mendation 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 some other obligatory language such
13、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 RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommenda
14、tion 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 process. As of the date of approval
15、 of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent d
16、atabase. ITU 2005 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.662 (07/2005) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Abbreviations 2 4 Classification of OA devices 2 5 Types of OA subsyste
17、ms 3 6 Characteristics of power amplifiers 4 6.1 Single-channel applications 4 6.2 Multichannel applications 4 7 Characteristics of pre-amplifiers. 5 7.1 Single-channel applications 5 7.2 Multichannel applications 5 8 Characteristics of line amplifiers 6 8.1 Single-channel applications 6 8.2 Multich
18、annel applications 6 9 Characteristics of optically amplified transmitters. 7 9.1 Single-channel applications 7 9.2 Multichannel applications 7 10 Characteristics of optically amplified receivers . 7 10.1 Single-channel applications 7 10.2 Multichannel applications 7 ITU-T Rec. G.662 (07/2005) 1 ITU
19、-T Recommendation G.662 Generic characteristics of optical amplifier devices and subsystems 1 Scope This Recommendation applies to discrete Optical Amplifier (OA) devices and subsystems to be used in transmission networks. It covers both Optical Fibre Amplifiers (OFAs) and Semiconductor Optical Ampl
20、ifiers (SOAs). The object of this Recommendation is to identify those generic characteristics specifiable for the use of OA devices (as power amplifiers, pre-amplifiers or line amplifiers) and OA subsystems (as optically amplified transmitters or optically amplified receivers), primarily for applica
21、tions in digital transmission, ensuring the maximum compatibility with ITU-T G-series Recommendations relating to line systems and equipments, for example, Recommendations such as ITU-T Recs G.957 or G.959.1. 2 References The following ITU-T Recommendations and other references contain provisions wh
22、ich, 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
23、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 Recommendation. I
24、TU-T Recommendation G.661 (1998), Definition and test methods for the relevant generic parameters of optical amplifier devices and subsystems. ITU-T Recommendation G.663 (2000), Application related aspects of optical fibre amplifier devices and subsystems. ITU-T Recommendation G.665 (2005), Generic
25、characteristics of Raman amplifiers and Raman amplified subsystems. ITU-T Recommendation G.691 (2003), Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers. ITU-T Recommendation G.692 (1998), Optical interfaces for multichannel systems with optical amplifiers. I
26、TU-T Recommendation G.955 (1996), Digital line systems based on the 1544 kbit/s and the 2048 kbit/s hierarchy on optical fibre cables. ITU-T Recommendation G.957 (1999), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. ITU-T Recommendation G.959.1 (2003),
27、Optical transport network physical layer interfaces. 2 ITU-T Rec. G.662 (07/2005) 3 Abbreviations This Recommendation uses the following abbreviations: BA Booster (power) Amplifier LA Line Amplifier OA Optical Amplifier OAR Optically Amplified Receiver OAT Optically Amplified Transmitter OFA Optical
28、 Fibre Amplifier PA Pre-Amplifier Rx (optical) Receiver SDH Synchronous Digital Hierarchy SOA Semiconductor Optical Amplifier Tx (optical) Transmitter 4 Classification of OA devices Different OA application categories are defined depending on the technology used and the utilization of the OA itself.
29、 Classification of optical amplifier technologies is given in IEC 61292-3. These categories are identified by a capital letter, a number and a lower case letter, as defined in clause 5/G.661. The power amplifier is a high saturation-power OA device to be used directly after the optical transmitter t
30、o 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 amplifier is a low noise OA device to be used between passive fibre sections to increase the distance covered before regeneration is
31、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 power amplifier is integrated with an optical transmitter, resulting in a higher power transmitter. The OAR is an OA subsystem in
32、which a pre-amplifier is integrated with an optical receiver, resulting in a higher sensitivity receiver. The distributed amplifier is a device configuration that provides amplification over an extended length of the optical fibre used for transmission, as by Raman pumping, and is thus distributed o
33、ver part or all of the transmission span. According to this criterion, an OA device (BA, PA or LA), inserted along an optical path, shall be considered a separate element placed between the reference points S and R defined in the ITU-T G-series Recommendations for line terminals and regenerators, as
34、 shown in the scheme of Figure 1. In the case of a booster amplifier, there would be no transmission fibre between the transmitter and the amplifier. Similarly, for a pre-amplifier, there would be no transmission fibre between the amplifier and the receiver. With reference to this figure, the input
35、and output characteristics of the OA device shall be specified at reference points Rand S, before and after the OA device, respectively. It is understood that, since the OA device is not a regenerator or a terminal equipment, these are virtual R and S points. ITU-T Rec. G.662 (07/2005) 3 Figure 1/G.
36、662 Scheme of insertion of an OA device A PA may include an optical filter, e.g., to minimize the contribution of OA device noise to the total noise as detected by the optical receiver, or to separate signals in some multiwavelength applications. Such a filter can be tuneable, manually or automatica
37、lly, to the signal wavelength and, in systems with multiple signals at different wavelengths, filtering may be needed around each wavelength. According to the definitions of BA, PA and LA, and with reference to Figure 1, the possible configurations of OA device applications can be schematized as fol
38、lows (here LA can represent one single line amplifier or two or more cascaded line amplifiers): a) Tx + BA + Rx; b) Tx + PA + Rx; c) Tx + LA + Rx; d) Tx + BA + PA + Rx; e) Tx + BA + LA + Rx; f) Tx + LA + PA + Rx; g) Tx + BA + LA + PA + Rx. 5 Types of OA subsystems OA subsystems covered by this Recom
39、mendation are OAs integrated either with the optical transmitter or with the optical receiver, in which either the output or the input port, respectively, is specified only. Both kinds of integration imply that the connection between the transmitter or the receiver and the OA is proprietary and shal
40、l not be specified. Consequently, a reference point S only can be defined for the specification of the OAT output characteristics after the OA, as shown in Figure 2, and a reference point R only can be defined for the specification of the OAR input characteristics before the OA, as shown in Figure 3
41、. As the PA, also the OAR may include an optical filter which can be tuneable, manually or automatically, to the signal wavelength. Figure 2/G.662 Scheme of insertion of an OAT 4 ITU-T Rec. G.662 (07/2005) Figure 3/G.662 Scheme of insertion of an OAR 6 Characteristics of power amplifiers 6.1 Single-
42、channel applications The following is the minimum list of relevant parameters for the specification of an OA device used as BA for single-channel applications: a) Input power range. b) Output power range. c) Power wavelength band. d) Signal-spontaneous noise figure. e) Input reflectance. f) Output r
43、eflectance. g) Pump leakage to input (applicable to OFAs only). h) Maximum reflectance tolerable at input. i) Maximum reflectance tolerable at output. j) Maximum total output power. 6.2 Multichannel applications The following is the minimum list of relevant parameters for the specification of an OA
44、device used as BA for multichannel applications: a) Channel allocation. b) Total input power range. c) Channel input power range. d) Channel output power range. e) Channel signal-spontaneous noise figure. f) Input reflectance. g) Output reflectance. h) Pump leakage to input (applicable to OFAs only)
45、. i) Maximum reflectance tolerable at input. j) Maximum reflectance tolerable at output. k) Maximum total output power. l) Channel addition/removal (steady-state) gain response. m) Channel addition/removal (transient) gain response. ITU-T Rec. G.662 (07/2005) 5 7 Characteristics of pre-amplifiers 7.
46、1 Single-channel applications The following is the minimum list of relevant parameters for the specification of an OA device used as PA for single-channel applications: a) Input power range. b) Output power range. c) Small-signal gain wavelength band. d) Available signal wavelength band. e) Tuneable
47、 wavelength range. f) Signal-spontaneous noise figure. g) Input reflectance. h) Output reflectance. i) Pump leakage to output (applicable to OFAs only). j) Maximum reflectance tolerable at input. k) Maximum reflectance tolerable at output. l) Maximum total output power. m) Small-signal gain. 7.2 Mul
48、tichannel applications The following is the minimum list of relevant parameters for the specification of an OA device used as PA for multichannel applications: a) Channel allocation. b) Total input power range. c) Channel input power range. d) Channel output power range. e) Channel signal-spontaneou
49、s noise figure. f) Input reflectance. g) Output reflectance. h) Pump leakage to output (applicable to OFAs only). i) Maximum reflectance tolerable at input. j) Maximum reflectance tolerable at output. k) Maximum total output power. l) Channel addition/removal (steady-state) gain response. m) Channel addition/removal (transient) gain response. n) Channel gain. o) Multichannel gain variation (inter-channel gain difference). 6 ITU-T Rec. G.662 (07/2005) 8 Characteristics of line amplifiers 8.1 Single-channel applications The following is the mini
