Highly reliable high-power 980-nm pump laser

We report on highly reliable, high-power, and high-performance 980-nm quantum-well laser chips and modules. Ridge waveguide laser diode chips with 750-mW output power and 500-mW fiber Bragg grating stabilized modules have been achieved and Telcordia-qualified. Long-term reliability tests show a very low failure rate of 400 FIT (failures in time) at 900-mA operating current or 500-mW module power. The kink-free fiber coupled module output power can be as high as 640 mW with grating stabilization, which produces very good wavelength stability and power stability. A further improved structure shows a record continuous-wave rollover chip power of 1.6 W for the 5-/spl mu/m-wide ridge waveguide laser diodes.     

Reliability estimate for semiconductor laser module ILPN-134

The reliability of the ILPN-134 is investigated laser module. The technique, which allows one to estimate what contribution is introduced by individual processes of aging of the laser diode and the optical system to the degradation of the laser module ILPN-134, is suggested. The activation energies of degradation processes, the standard deviations, and the failure rates of the laser diode and the optical system are determined.     

Present problems of power module packaging technology

An overview of the problems encountered concerning power module performance and reliability is given and the main failure mechanisms are discussed. Experimental and simulation methods for the transient thermal characterisation of semiconductor packages are presented. An identification procedure that allows establishing the physical correspondence between the RC cells of the thermal model and the layers that constitute the electronic package is proposed. The results of tests on a number of commercial Smartpack^® modules provide useful information about the influence of materials properties and geometry on the step response. These could be used for package quality control and reliability investigations.     

Reliability and lifetime evaluation of different wire bonding technologies for high power IGBT modules

IGBT modules for power transmission, industrial and traction applications are operated under severe working conditions and in harsh environments. Therefore, a consequent design, focused on quality, performance and reliability is essential in order to satisfy the high customer requirements. One of the main failure mechanisms encountered in high power IGBT modules subjected to thermal cycles is wire bond lift-off, which is due to the large thermal expansion coefficient mismatch between the aluminum wires and the silicon chips. The paper describes various bonding technologies using different wire materials directly bonded onto chip metallisation as well as the ABB solution where the wire is bonded on a thin molybdenum strain buffer soldered onto the chip. We assess in the present paper the potential of these technologies to enhance module reliability and lifetime through a power cycling test. Failure analysis results are presented and the failure mechanisms related to each technology are explained in detail.     

Crystalline silicon PV module degradation after 20 years of field exposure studied by electrical tests,electroluminescence, and LBIC

Standardized tests to assure the reliability of photovoltaic modules and to detect possible early failures of modules when exposed in the field, due to design flaws or to the use of non‐appropriate materials, have played an important role in the successful growth of photovoltaic market in recent years. In order for this growth to be sustainable in coming years, it is crucial to keep the confidence of investors in standard well‐established technologies and to increase confidence in new emerging technologies. For these reasons, there is an ongoing work for the improvement of current tests and for the development of new ones, which besides assuring module reliability in the field, have also the aim of predicting their lifetime. The analysis of degradation of modules that were field exposed over a long period of time is fundamental to identify the degradation mechanisms and to collect statistics on modules behavior. This work focuses on the analysis of the change of the photovoltaic module electrical characteristics after approximately 20 years of field exposure, considering differences in the design of cells that were used for the production of these modules, which were identified by detailed visual inspection. Failure modes were investigated by comprehensive visual inspection and the use of spatially resolved analysis techniques as follows: laser beam‐induced current and electroluminescence. The main failure mode identified was yellowing of the encapsulant. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

Assessing the reliability and degradation of photovoltaic module performance parameters

Photovoltaic (PV) modules are renowned for their reliability. However, some modules degrade or even fail when operating outdoors for extended periods. To reduce the degradation, and the number of failures, extensive research is needed on the performance of PV modules. The aim of this study was to establish a photovoltaic degradation and failure assessment procedure. This procedure should assess all parameters of PV modules to completely analyze any observed degradation or failure. In this paper some degradation modes of PV modules are discussed and a procedure used to assess these degradation modes is then presented. Results obtained by subjecting Copper Indium Diselenide (CIS), single and triple junction amorphous silicon (a-Si and a-SiGe), Edge-defined Film-fed Growth (EFG) silicon and mono-crystalline silicon (mono-Si) modules to the assessment procedure are presented and discussed. Results obtained indicate that the thin-film modules degrade by up to 50% in performance after an initial outdoor exposure of 130 kWh/m/sup 2/. Visual inspection revealed that both crystalline modules had cracked cells. The mismatch due to the cracked cell in the EFG-Si module, however, was limited by the interconnect busbars. This paper accentuates the importance of characterizing all module performance parameters in order to analyze observed degradation and failure modes.     

Thermal reliability prediction and analysis for high-density electronic systems based on the Markov process

Thermal-mechanical fatigue is one of the main failure modes for electronic systems, particularly for high-density electronic systems with high-power components. Thermal reliability estimation and prediction have been an increasing concern for improving the safety and reliability of electronic systems. In this paper, we propose a stochastic process prediction model to estimate the thermal reliability of an electronic system based on Markov theory. We first divided the high-density electronic systems into four modules: the energy transformation and protection module, the electronic control module, the connection module, and the signal transmission and transformation module. By integrating failure and repair characteristics of the four modules, a stochastic model of thermal reliability analysis and prediction for a whole electronic system was built based on the Markov process. The feature parameters of thermal reliability evaluation, including thermal reliability, thermal failure probability, mean time between thermal faults, and thermal stable availability, were derived based on our comprehensive model. Finally, we applied the model to an indoor electronic system of DC frequency conversion conditioning. The thermal reliability was estimated and predicted using tested failure and debugging repair data. Effective methods for improving thermal reliability are presented and analyzed based on the comprehensive Markov model.     

Reliability test and failure analysis of high power LED packages

A new type application specific light emitting diode(LED) package(ASLP) with freeform polycarbonate lens for street lighting is developed,whose manufacturing processes are compatible with a typical LED packaging process.The reliability test methods and failure criterions from different vendors are reviewed and compared.It is found that test methods and failure criterions are quite different.The rapid reliability assessment standards are urgently needed for the LED industry.85℃/85 RH with 700 mA is used to test our LED modules with three other vendors for 1000 h,showing no visible degradation in optical performance for our modules,with two other vendors showing significant degradation.Some failure analysis methods such as C-SAM,Nano X-ray CT and optical microscope are used for LED packages.Some failure mechanisms such as delaminations and cracks are detected in the LED packages after the accelerated reliability testing.The finite element simulation method is helpful for the failure analysis and design of the reliability of the LED packaging.One example is used to show one currently used module in industry is vulnerable and may not easily pass the harsh thermal cycle testing.     

Plastic module of laser diode and photodiode mounted on planarlightwave circuit for access network

Low-cost plastic packaging of laser diodes and photodiodes mounted on planar lightwave circuit (PLC) platform are developed and its reliability is confirmed under various environmental and endurance tests. The high performance of the module is maintained under reliability tests, such as high-humidity high-temperature tests (85°C, 85%RH) and temperature cycling tests (-40°C/85°C). No laser diodes show any device characteristics change during environmental tests and their stability has very little dependence on current bias. Although the photodiodes show an increase in leakage current under high-temperature high-humidity tests and the rate of leakage current increase is proportional to the square root of bias voltage, the increase is negligible for system use. These plastic modules can be applied to actual access networks and other fiber-optic networks     

Reliability testing of high-power multi-chip IGBT modules

Power-cycling tests are among the most important tools used for evaluating the reliability of power modules. They are in most cases carried out at the rated module current and during a relatively short cycle time, i.e. under worst-case operating conditions. Test conditions must be defined which also permit information to be obtained about failure mechanisms in the various parts of the module. This paper describes the measurement of the temperature distribution, the test conditions, the rates of temperature change in modules with 36 semiconductor components as well as the results of power-cycling tests in which the thermomechanical stress principally affects the substrate-baseplate interface.     

PSpice在高功率固体激光能源系统中的应用

在神光能源系统模块中,依据脉冲氙灯放电特性及氙灯放电回路的技术要求,采用仿真软件OrCAD PSpice分别从脉冲氙灯的五路放电、氙灯能量分配及能源模块在放电过程中存在的故障三个方面进行模拟仿真并给出仿真结果,并与实际装置运行数据进行比较分析,其仿真的结果与实际理论分析结论基本一致,验证了仿真模型及过程的可靠性,这为高功率激光装置的电子计算机辅助设计和分析提供了一种新途径。     

某气密封毫米波收发组件的故障统计与分析

毫米波组件作为毫米波电子系统的重要组成部分,其可靠性和故障率在很大程度上决定了整个毫米波系统的工作状态。目前,关于毫米波组件在批量使用过程中的可靠性情况和故障数据还鲜有研究。收集了某批量生产的毫米波收发组件在交付和使用中所出现的故障,并对故障进行了统计和分析,最后根据统计结果给出了技术和管理方面的改进建议。     

Optical output power fluctuation due to reflected lightwaves in laser diode modules

The optical output power fluctuation caused by axial displacement of optical components in an actual laser diode module subject to the influence of reflected light waves has been theoretically investigated. Results are based on the comparison of data from two analytical methods. One takes the emission spectrum shift of a laser diode into consideration while the other ignores wavelength shift. It has been clarified that the differences between these two results are relatively small, as long as it can be assumed that the laser diode oscillates in the initial longitudinal mode. Suppression methods for the reflected lightwaves are also discussed. Practical and efficient antire-flection techniques for the laser diode modules are presented.     

Transmission characteristics of DFB laser modules for analogapplications

Analog transmission characteristics of highly linear 1.3- and 1.55-μm distributed feedback (DFB) laser modules are described. To obtain high-power and high-performance DFB lasers, the bias dependence of distortion characteristics is discussed. The carrier-to-noise ratio, the composite second-order distortion, and the composite triple beat of the DFB laser module which is developed for analog CATV applications are presented. The analog transmission characteristics, such as CNR degradation, after fiber transmission, dispersion-induced distortion, and the influence of reflection, have been made clear. The stable high linearity of the DFB laser also has been confirmed by the composite distortion measurement under an accelerated aging test     

A novel fiber alignment shift measurement and correction technique in laser-welded laser module packaging

A novel measurement and correction technique employing an ultra-high-precision laser displacement meter (LDM) with a 20-nm resolution to probe the postweld-shift (PWS)-induced fiber alignment shifts in laser-welded laser module packaging is presented. The results show that the direction and magnitude of the fiber alignment shifts induced by the PWS in laser-welded laser module packaging can be quantitatively determined by four parameters: the lateral position (r), the position angle (/spl alpha/), the swing angle (/spl theta/), and the tilt angle (/spl psi/). Further studies show that the deformation of the lateral shift and the position angle are the dominant mechanisms that determine the fiber alignment shifts induced by the PWS. This clearly indicates that the PWS can be quantitatively corrected timely by applying a single weld spot on the negative lateral shift and the position angle to compensate for the fiber alignment shifts. In comparison with previous studies of the PWS correction by a qualitatively estimated technique, this LDM technique has significantly provided an important tool for quantitative measurement and correction to the effect of the PWS on the fiber alignment shifts in laser-welded laser module packaging. Therefore, the reliable laser modules with high yield and high performance used in low-cost lightwave transmission systems may be developed and fabricated.     

200-Mb/s/ch 100-m optical subsystem interconnections using8-channel 1.3-μm laser diode arrays and single-mode fiber arrays

Synchronous parallel optical-fiber transmission is an attractive method for providing increased interconnection throughput and higher density in advanced information systems. Skew suppression (reducing transmission delay time variation), error-free fully DC-coupled data transmission capability, compactness, and low power consumption of modules are important requirements. In order to meet these requirements, we developed optical subsystem interconnections using long-wavelength laser diode arrays and single-mode fiber arrays. The major design criteria are discussed, especially as they are related to skew due to laser diode turn-on delay and receiver input optical power variation. The use of low-threshold-current laser diode arrays is an important design requirement. Based on the design criteria discussed in this work, we demonstrated and channel 200-Mb/s/ch 100-m transmission using compact (0.18 cc/ch/module), low power (total 280 mW/ch), fully integrated transmitter and receiver modules with an ECL (emitter coupled logic) interface. These modules include our new laser diode arrays with low threshold current of 3.2 mA. Performance results showed that these modules are very effective as interconnections between synchronously operating subsystems     

Reliability analysis of recovery blocks with nested clusters offailure points

A Markov model is developed to obtain first and second moments of the number of successfully processed input-points for recovery blocks with a primary module and two alternate modules. A nested structure of clusters of failure points is assumed. When in a failure cluster of the primary module, the input sequence encounters clusters of failure points belonging to the first alternate module, in which case the second alternate is invoked. Some special cases are discussed in detail. A Markov chain model for one of the well-documented fault-tolerant software techniques, the recovery block, is analyzed. The model is intended to study recovery block reliability when the sequence of input values traverses nested clusters of failure points in the input domain. The method of solution exploited the specific structure of the state-transition diagram, which is two-dimensional. Moments of the number of successfully processed input points were obtained by recursively solving infinite systems of linear equations     

Reliability in Digital Systems with Asymmetrical Failure Modes

Most present-day reliability schemes using redundancy to mask the failure of individual logic modules employ majority voting with the assumption that the replicated modules have symmetrical failure characteristics. An analysis is presented of such schemes when the modules exhibit asymmetrical failure modes; that is, the probability that a module fails with a 0 output is not equal to the probability that it fails with a 1 output. A general expression is presented which gives the reliability of a network consisting of n identical modules feeding a k-out-of-n voter. It is shown that a simple majority element does not always represent the optimal choice. Plots illustrating the results are included.     

Historical overview and future of optoelectronics reliability for optical fiber communication systems

The failure modes and failure mechanisms in optoelectronic devices, such as laser diodes, Light-emitting diodes, and photodiodes, are reviewed through a historical overview of device reliability and their future reliability is briefly discussed.     

多芯片系统可靠性技术

在对电子产品可靠性技术的最新发展趋势进行了展望之后, 对多芯片系统的可靠性技术作了较全面的评述。对研究多芯片系统可靠性的失效率预测方法和失效物理评价方法以及多芯片系统的关键技术问题着重进行了细致的剖析并提出了解决的思路