激光二极管寿命测试方法研究

文中介绍了半导体激光二极管(LD) 寿命测试的理论依据,给出了寿命测试的数学模 型,并据此设计了LD 高温加速寿命自动测试系统。系统通过采集恒流工作LD 的平均输出光功率随时间变化的信息,绘制LD 的老化曲线,即恒流条件下的P - t 曲线,或通过采集恒功工作LD 的工作电流随时间变化的信息,即恒功条件下的I - t 曲线,然后推断LD 正常条件下的使用寿命。     

带有半导体激光器寿命检测的驱动电源的设计

作者研制了一种带有半导体激光器(LD)寿命检测的驱动电源,该电源通过高精度的采样电路和分步调整方式,不仅可以达到恒功率控制,而且能够检测LD的工作寿命,具有寿命预告警、失效保护功能,从而保证LD工作的可靠性、连续性.     

一种半导体激光器参数测试系统的设计

提出一种针对小功率激光器的0～50 mA可调的恒流驱动测试系统.系统采用ADuC814芯片作为控制核心,实现高稳定度的LD驱动和温度控制,实时采集来自LD的各项数据,传递给计算机.计算机对测试系统进行灵活控制、操作,并对测试数据进行处理、分析.该系统安全可靠,是一种适用于小功率激光器的较为理想的测试系统.     

大功率半导体激光器的可靠性研究

文中介绍了半导体激光器寿命测试的理论依据,给出寿命测试的数学模型,据此对InGaAsP/GaAs有源区无铝的808nm大功率半导体激光器进行高温恒流加速老化实验,得到器件在高温下的寿命,利用外推公式推算出激光器在室温条件下工作的寿命可超过30000小时。讨论了实验中出现的灾变退化,提出了防止灾变退化的几种方法。     

用时间分辨荧光光谱研究乙酸-水溶液的聚合特性

对284nm激发光照射不同体积百分比乙酸一水溶液的峰值荧光强度时间衰变曲线进行了实验测量,并检测了不同紫外光激励下334nm荧光强度随时间的衰变过程,将获得的荧光衰减动力学曲线采用指数拟合方法进行了解卷积处理,测试了相应的荧光寿命。分析了乙酸-水溶液中线状二聚物（LD）缔合结构的变化规律,计算了混合物质中不同组分的浓度...     

基于单片机的半导体激光器应用控制技术

针对半导体激光器(LD)应用领域十分广泛的特点,提出了一种新型LD功率(P)-电流(Ⅰ)-电压(Ⅴ)的自动测试方法.该方案采用华邦51系列单片机(SCM)W78E58BP作为控制核心,实现了高稳定度的LD连续及脉冲驱动、恒流控制及功率、电压采集.LD控制单元中,应用负反馈技术实现注入电流Ⅰf、驱动电压Ⅴf和光功率Po的高稳定控制,电流控制精度为±0.1%;单片机控制电信号的放大、保持和采集,模拟、数字相结合,提高了信号处理的精度.最后,给出了通过RS-232接口对LD进行PIV测试的曲线及相关参数的测试结果,并给出了误差分析.该测试方法已得到广泛应用.     

半导体激光器在不同制冷条件下散热研究

对半导体激光器在不同制冷条件下的散热进行实验研究.通过设计温度测试系统,分别在被动制冷、单条水路主动制冷和U型回路主动制冷的条件下,测量了多个高功率LD在不同工作电流下的温度,研究了在不同制冷条件下LD温度随电流的变化,发现U型回路主动制冷条件下,LD的散热效果最好.     

LED/LD P-I、V-I和光谱特性计算机辅助测试系统

将智能化的光功率计、数字电压表等测量仪表通过IEEE488母线与AppleⅡ微型计算机相连,组成了LED/LD器件特性的计算机辅助测试系统。它能够自动测量器件的P-I、V-I和光谱特性,然后用绘图仪画出上述各特性定标的曲线并在图上标出特定电流下P和V的数值以及器件的峰值波长、谱线宽度等特性参数。与人工逐点测试或x-y记录仪测试相比,测试的速度快、精度高、重复性好,做到了由计算机将测量、数据采集和处理、特性曲线图表的制作等项工作一次完成。     

基于双光斑外缘曲线的高能面阵LD发散角测量方法

提出一种适合高能面阵LD发散角测试的新方法.该方法以激光光束传输到不同距离处的2条光斑外缘曲线的几何特征为基础来求LD的发散角,而2条光斑外缘曲线分别由2个半径不同的半圆环探头的旋转扫描探测获得.该方法解决了高能面阵LD发散角测试中的2个关键问题:一是现有测试方法中把面阵LD的面发光直接当作点光源引起的测试误差;二是避免了因LD功率过大而损坏和烧毁探测器.实验表明:该测试方法能够准确、可靠地测试高能面阵LD的发散角.     

LD参数连续测试系统研究

本文介绍了一种新型半导体激光二极管（LD）参数连续测试系统，它采用了高精度的数据采集技术、超强的数据处理技术及精密机械定位技术，可对LD的P－I和V－I曲线及相关参数进行连续测试、显示、存储、管理和打印，测量速度快，测量精度高，操作方便。     

从CLEO'98看半导体激光器的最新进展

根据ＣＬＥＯ’９８ 会议报道的有关内容,综述了半导体激光器的发展状况。重点叙述了大功率ＬＤ、可见光ＬＤ、中红外ＬＤ 及垂直腔面发射半导体激光器（ＶＣＳＥＬ） 的最新研究进展     

Fabrication of room temperature continuous-wave operation GaN-based ultraviolet laser diodes

Two kinds of continuous-wave GaN-based ultraviolet laser diodes (LDs) operated at room temperature and with different emission wavelengths are demonstrated.The LDs epitaxial layers are grown on GaN substrate by metalorganic chemical vapor deposition,with a 10×600 μm2 ridge waveguide structure.The electrical and optical characteristics of the ultraviolet LDs are investigated under direct-current injection at room temperature. The stimulated emission peak wavelength of first LD is 392.9 nm,the threshold current density and voltage is 1.5 kA/cm² and 5.0 V,respectively.The output light power is 80 mW under the 4.0 kA/cm² injection current density. The stimulated emission peak wavelength of second LD is 381.9 nm,the threshold current density the voltage is 2.8 kA/cm² and 5.5 V,respectively.The output light power is 14 mW under a 4.0 kA/cm² injection current density.     

半导体激光器辐照损伤效应实验研究进展

半导体激光器(LD)工作在空间辐射或核辐射环境中时,会受到辐照损伤的影响而导致器件性能退化。文章回顾了不同时期研制的LD(从早期的GaAs LD到量子阱LD和量子点LD)在辐照效应实验方面的研究进展,梳理了国际上开展不同辐射粒子或射线(质子、中子、电子、伽马射线)诱发LD辐射敏感参数退化的实验规律,分析总结了当前LD辐照效应实验方法研究中亟待解决的关键技术问题,为今后深入开展LD的辐照效应实验方法、退化规律、损伤机理及抗辐射加固技术研究提供理论指导和实验技术支持。     

多发光区大功率激光器的热特性分析

通过电学温敏参数法测得多发光区大功率激光器瞬态加热响应曲线,利用结构函数法给出了多发光区激光器热阻构成,分析了多发光区激光器热特性。通过串并联热阻网络模型刻画了单发光区、两发光区、四发光区激光器的热阻构成,给出了激光器芯片热阻与发光区个数之间的定量关系。实验结果表明,不同发光区激光器的芯片级热阻随着发光区数量的增加成比例减小,而封装级热阻不变,这对激光器热设计提供了重要的参考准则。     

Influence of Bonding Temperature and Applied Load on the Bonding Integrity and Optical Performance of Face-Down Bonded Ridge-Waveguide Lasers

The effects of bonding temperature and applied load on the mechanical integrity of 80Au-20Sn solder joints and the optical performance of laser diodes (LDs) are presented. Insufficient solder wetting at 280°C and poor joint integrity at an applied load below 0.196 MPa resulted in solder failure during die shear test. As the bonding temperature and applied load increased, the joint integrity and the optical performance improved. Shear testing further showed fracture in the LD due to the high mechanical strength of 80Au-20Sn solder and good adhesion properties of the solder joint. Microstructure studies showed good metallurgical stability with little interfacial intermetallic compound (IMC) formed. However, beyond an applied load of 0.523 MPa, the LD performances degraded due to modification of the bandgap energy in the active region. From our experimentation, a bonding window with good bonding integrity and high optical performance was, nevertheless, achieved.     

Lipid droplets: size matters

The lipid droplet (LD), an organelle that exists ubiquitously in various organisms, from bacteria to mammals, has attracted much attention from both medical and cell biology fields. The LD in white adipocytes is often treated as the prototype LD, but is rather a special example, considering that its size, intracellular localization and molecular composition are vastly different from those of non-adipocyte LDs. These differences confer distinct properties on adipocyte and non-adipocyte LDs. In this article, we address the current understanding of LDs by discussing the differences between adipocyte and non-adipocyte LDs.     

Electrical Derivative Measurement of High-Power InGaAs LDs Under Scanning Current with Variable Step

For the large driving current of high-power semiconductor Laser diodes (LDs), a modified method to measure the electrical derivative of LDs under scan-ning driving current with variable step length is proposed, which is to achieve the fast and accurate measurement of optical and electrical characteristic parameters of LDs with a relatively small data acquisition. The experimental re-sults show that, with fewer measurements, this method can effectively and accurately measure and extract the LDs corresponding parameters including threshold cur-rent (Ith), voltage-current characteristic (V-I), luminous power-current relation (P-I), electrical derivative curve (IdV/dI-I). The wavelet transformation singularity testing results of the threshold current also verify the accuracy, reliability, and advantage of this method.     

窄线宽可调谐外腔半导体激光器阵列

介绍一种半导体激光器(LDs)阵列的外腔可调谐系统。腔体是Littrow结构,2个透镜将光栅选取的锁模光信号形成颠倒阵列像反馈回各个LD中。系统容易调整,对中心波长810nm、输出功率20W的单排24管LDs阵列,在光学元件参数均非最佳的情况下,获得线宽0．5nm(230GHz)、可调范围近30nm和输出功率为LDs阵列自由运行时的60％。实验结果表明,阵列中单个LD接收到的锁模信号并不必是自己发出的光,而可以来自阵列中其它LDs;此外,只要阵列中部分LDs获得锁模信号,即可达到全阵列锁模的目的。     

Frequency separation locking and synchronization for FDM opticalsources using widely frequency tunable laser diodes

A laser diode (LD) frequency separation locking method (called the reference pulse method) is proposed. This method has advantageous features for frequency division multiplexing (FDM) networks from the viewpoint of frequency separation stability with a strict frequency separation standard, modulation format independence, controllability over a large number of LDs, and frequency synchronization capability. Frequency locking experiments, using four and ten controlled LDs, confirmed that the control system using the method can stabilize frequency spacing for more than 100 LDs. The frequency fluctuation is suppressed to less than 10 MHz. Frequency synchronization, utilizing the reference pulse method, is proposed and demonstrated experimentally for two controlled LD groups, each consisting of three LDs. Frequency discrepancy between two LD groups was only 2.7% of the frequency separation. Required frequency-swept light power and controlled LD power at the detector input for frequency synchronization indicate that more than 50000 LD groups within a 10 km area, each having 100 LDs, can be synchronized simultaneously