1、 IEC/TR 62572-2 Edition 1.0 2008-09 TECHNICAL REPORT Fibre optic active components and devices Reliability standards Part 2: Laser module degradation IEC/TR 62572-2:2008(E) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2008 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified
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9、s and devices Reliability standards Part 2: Laser module degradation INTERNATIONAL ELECTROTECHNICAL COMMISSION U ICS 33.180; 31.260 PRICE CODE ISBN 2-8318-9993-1 Registered trademark of the International Electrotechnical Commission 2 TR 62572-2 IEC:2008(E) CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.
10、7 2 Normative references .7 3 Terms and definitions .7 4 Laser diode and laser module failure mechanisms8 4.1 General .8 4.2 Description of the main failure mechanisms which affect laser diodes and laser modules9 4.2.1 Laser diodes9 4.2.2 Monitor photodiode13 4.2.3 TEC and thermistor .13 4.2.4 Packa
11、ging and optical fibre14 5 Guidance on testing .14 5.1 Service life tests General .14 5.2 Scale of testing .15 5.3 Screening of components (including burn-in).15 5.3.1 Laser diodes15 5.3.2 Monitor photodiode16 5.3.3 Other components of the laser module 16 6 Guidance on the use of failure criteria du
12、ring testing 16 7 Guidance on reliability predictions 19 7.1 Lifetime predictions .19 7.2 Failure rate prediction .21 Figure 1 An example of cross-section for laser module 9 Figure 2 Cross-section through a typical heterostructure laser (bonded section side up).10 Figure 3 Schematic diagram of DSD a
13、nd DLDs viewed from the direction perpendicular to the (001) substrate .11 Figure 4 Non-linearities in laser-current characteristics18 Figure 5 “Bathtub” failure rate curve.22 Figure 6 Example of cumulative failure plot showing log-normal distribution of laser failure rate. The sample number tested
14、is 33. .23 Figure 7 Calculate failure rates as a function of service term for components having a log-normal lifetime distribution with a median life of 10 6h and dispersion in the range 0,5 to 2,0 23 Table 1 Example of laser diode screening and burn-in conditions 15 Table 2 Example of monitor photo
15、diode screening conditions 16 Table 3 Example of life test failure criteria .17 Table 4 Example of additional failure criteria for laser module service life tests .19 Table 5 Example of failure criteria for laser modules after temperature cycling testing and high-temperature storage testing19 Table
16、6 Recommended values of activation energy for lifetime predictions (when an experimentally determined value is not available, i.e. default values)21 TR 62572-2 IEC:2008(E) 3 Table 7 Coefficient for upper and lower level of median life in log-normal distribution, (tmp/tmh)1/ .26 Table 8 Multiplying c
17、oefficient for upper and lower level of dispersion27 Table 9 Failure rate for an exponential lifetime distribution 28 4 TR 62572-2 IEC:2008(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FIBRE OPTIC ACTIVE COMPONENTS AND DEVICES RELIABILITY STANDARDS Part 2: Laser module degradation FOREWORD 1) The
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27、references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible
28、 for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. However, a technical committee may propose the publication of a technical report when it has collected data of a different kind from that which is normally published as an
29、 International Standard, for example “state of the art“. IEC 61751-2, which is a technical report, has been prepared by subcommittee 86C: Fibre optic systems and active devices of IEC technical committee 86: Fibre optics, based on the Standard IEC 61751 prepared by subcommittee 47C: Optoelectronic,
30、display and imaging devices, of IEC technical committee 47: Semiconductor devices. The field of this technical report will henceforth be placed under the responsibility of IEC technical committee 86: Fibre optics. TR 62572-2 IEC:2008(E) 5 The text of this technical report is based on the following d
31、ocuments: Enquiry draft Report on voting 86C/833/DTR 86C/847/RVC Full information on the voting for the approval of this technical report can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of
32、all parts of IEC 62752 series, under the general title Fibre optic active components and devices Reliability standards, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web si
33、te under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. 6 TR 62572-2 IEC:2008(E) INTRODUCTION The
34、laser modules covered by this technical report are purchased by a system supplier (SS) to be inserted in equipments which in turn are supplied/sold to a system operator (SO), for example, a telecommunications company (see definitions in Clause 3). For the system operator to act as an informed buyer,
35、 knowledge of the potential risks posed by the use of critical components is required. Optoelectronic component technology is continuing to develop. Consequently, during product development phases, many failure mechanisms in laser modules have been identified. These failure mechanisms, if undetected
36、, could result in very short laser lifetime in system use. TR 62572-2 IEC:2008(E) 7 FIBRE OPTIC ACTIVE COMPONENTS AND DEVICES RELIABILITY STANDARDS Part 2: Laser module degradation 1 Scope This technical report deals with reliability assessment of laser modules used for telecommunication guidance on
37、 testing, use of failure criteria and reliability predictions is provided. This technical report provides guidance on: the testing that a system supplier should ensure is in a place prior to procurement of a laser module from a laser module manufacturer; a range of activities expected of a system su
38、pplier to verify a laser module manufacturers reliability claims. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced docum
39、ent (including any amendments) applies. IEC 60068-2-1: Environmental testing Part 2-1: Tests. Tests A: Cold IEC 60068-2-14: Environmental testing Part 2-14: Tests. Test N: Change of temperature IEC 60747-1: Semiconductor devices Part 1: General IEC 60749-1: Semiconductor devices Mechanical and clima
40、tic test methods Part 1: General ISO 9000: Quality management systems Fundamentals and vocabulary MIL-STD-883G: Test method standard, microcircuits 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 laser module packaged assembly containing a la
41、ser diode with/without photodiode NOTE The module may also include a cooler and temperature sensor to enable laser temperature to be controlled and monitored. The optical output is normally via an optical fibre pigtail. 3.2 submount substrate upon which a laser is mounted for assembly into the subca
42、rrier 8 TR 62572-2 IEC:2008(E) 3.3 subcarrier substrate upon which a laser diode and/or photodiode may be mounted for assembly into the laser module NOTE Components on submounts are also subject to qualification testing. 3.4 laser module manufacturer (LMM) manufacturer of laser modules who provides
43、devices meeting the requirements of the relevant detail specification (DS) and the customers reliability requirements 3.5 system supplier (SS) manufacturer of telecommunications/data transmission equipment containing optoelectronic semiconductor lasers, i.e. laser module customer 3.6 system operator
44、 (SO) network operator of telecommunications/data transmission equipment containing optoelectronic semiconductor lasers in the transmission path NOTE The system may also be part of other more extensive systems, for example telecommunications, rail, road vehicles, aerospace or weapons. 3.7 capability
45、 qualifying components (CQC) components selected to represent critical stages of the process and limiting or boundary characteristics of mechanical and electro-optic design. 4 Laser diode and laser module failure mechanisms 4.1 General Much of the published laser reliability data (and also reliabili
46、ty data from laser manufacturers) is from the service life testing of laser chips bonded onto submounts or special headers. The results usually show increasing threshold or operating currents leading to eventual failure. However, other laser characteristics can also degrade and should be monitored d
47、uring life testing, for example, light-output spectrum. Practical laser transmitters, as used in fibre transmission systems, contain several other important piece parts and components that are also vulnerable to failure. For example, reduced fibre output power, due to instability in the fibre to las
48、er chip alignment, is a significant failure mechanism in laser modules. Less information is available on the stability of the output from receptacle packages. Various kinds of laser module have been used in fibre transmission systems. An example structure for laser module is shown in Figure 1 in whi
49、ch the laser chip is mounted on a submount within a dual-in-line package with a fibre pigtail. The temperature of the laser submount is often controlled using a TEC, with a thermistor as a temperature sensor. Some distributed feedback laser modules for use in high bit-rate optical fibre systems also contain optical isolators to prevent reflected optical power from adversely affecting the laser operation. Advanced modules containing integrated ci
