单量子阱激光器小信号频响特性模拟分析

量子阱激光器具有优良的性能 ,是宽带通信的重要光源。基于三层速率方程的量子阱激光器模型在明确引入了过渡态的概念后 ,对于量子阱中载流子的传输过程就有了更完整的描述。文中运用三层速率模型 ,对小信号调制下单量子阱激光器的频率响应进行模拟分析。与公开发表的文献资料比较 ,所设计的模型精度高 ,易于分析 ,有实用意义。     

量子阱带间跃迁探测器基础研究（特邀）

在最近的实验中,PN结型量子阱结构被观察到反常的载流子输运情况,其相应的物理机制和载流子输运模型被提出。通过系统实验观察到,PN结量子阱结构材料在共振激发模式下,仍可测出开路电压或短路电流。对比开路和短路情况下的光致荧光（PL）光谱,发现短路下PL强度明显降低。这说明短路状态下的光生载流子没有被限制在量子阱内,而是逃逸出结区。这种载流子逃出量子阱的现象却没有在等量偏压下的NN型量子阱结构中发现,说明载流子逃出量子阱并非由传统的热激发或隧穿的作用导致。据此,笔者提出了相应的物理机制和载流子输运模型对此现象进行解释,认为光生载流子能在PN结内建电场的作用下直接逃出量子阱,并且辐射复合发光发生在载流子逃逸过程之后。     

（英）中红外量子级联激光器输运特性的仿真

基于一种非局域化的输运模型,对不同结构不同温度下的中红外量子级联激光器的输运特性进行了仿真。在这个模型中,利用量子隧穿、微带隧穿以及热载流子输运等长程载流子输运模型,对传统的扩散-漂移方程进行了矫正.并将基于上述集成模型的计算结果和实验结果进行了比较,通过拟合参数的合理设置,计算结果和实验结果得到了很好的吻合.     

InGaAsP量子阱激光器结构与阈值电流密度的关系

计入俄歇复合过程的影响,从理论上研究了InGaAsP多量子阱激光器的阈值电流密度。在评述辐射和俄歇过程中考虑了二维载流子在量子化次能带间的所有可能跃迁。俄歇复合电流强烈地依赖于量子阱结构,这样就需要对量子阱激光器的结构进行精心的设计。此外,还阐述了能获得最低阈值电流密度的InGaAsP多量子阱激光器的结构设计程序。     

一个简单的量子阱激光器等效电路模型

给出一个新的量子阱激光器等效电路模型,由量子阱激光器单模速率方程推导得到并在电路模拟程序ＳＰＩＣＥ中完成。该模型考虑了热辐射效应和分离限制区域（ＳＣＨ）内的载流子工作情况,给出了新的光增益表达式。并利用该模型对单量子阱激光器的小信号特性和瞬态大信号特性进行了预测,模拟结果表明和速率方程的直接求解结果吻合很好。     

基于三层模型的多量子阱激光器调制特性的SPICE模拟

从三层速率方程推导出多量子阱激光器的等效电路模型 ,并用数量而不是密度来描述载流子及光子行为 ,避开了传统方法中处处都要涉及到的体积参量 ,解释了传统的二层模型所不能解释的多量子阱 (MQW )激光器中多量子阱内载流子不均匀分布问题 ,用SPICE进行了调制特性的模拟及讨论。激光器件的模拟以层次性的方式实现 ,对使用EDA工具进行集成光学器件和系统仿真进行了探索。     

高功率980nm非对称宽波导半导体激光器设计

设计了980nm非对称宽波导InGaAs/InGaAsP量子阱激光器,并在结构中插入电流阻挡层,有效地阻止载流子的泄露。用LASTIP软件对980nm非对称宽波导量子阱激光器进行理论模拟,与传统的980nm对称宽波导量子阱激光器相比,非对称宽波导量子阱激光器波导和量子阱之间有更小的能带差,非对称宽波导结构具有更低的阈值电流,更高的斜效率以及更低的阻抗,所以带有电流阻挡层的980nm非对称宽波导InGaAs/InGaAsP量子阱激光器有更高的光电转换效率和输出功率。     

量子阱DBR微腔激光器中自发发射的控制

应用腔量子电动力学和量子阱物理 ,计算了量子阱 DBR微腔激光器的自发发射谱 .发现由于 DBR微腔和量子阱分别对光子和载流子的限制 ,单方向的自发发射可以增进约三个量级 ,总的自发发射增强一个量级 .     

2μm InGaAsSb/AlGaAsSb应变补偿量子阱结构的数值研究

为了降低2μm半导体激光器的阈值电流并提高器件的输出功率,设计了InGaAsSb/AlGaAsSb应变补偿量子阱结构,并利用SimLastip软件对器件进行了数值模拟.研究表明,在势垒中适当引入张应变可以改善量子阱的能带结构,提高对载流子的限制能力.当条宽为120 μm、腔长为1 000 μm时,采用应变补偿量子阱结构的激光器的阈值电流为91 mA,斜率效率为0.48 W/A.与压应变量子阱激光器相比,器件性能得到明显的改善.     

量子阱DBR微腔激光器中自发发射的控制

应用腔量子电动力学和量子阱物理,计算了量子阱DBR微腔激光器的自发发射谱.发现由于DBR微腔和量子阱分别对光子和载流子的限制,单方向的自发发射可以增进约三个量级,总的自发发射增强一个量级.     

Resonant tunneling in quantum heterostructures: electron transport,dynamics, and device applications

The current understanding of the resonant tunneling process of electrons in double-barrier (DB) diodes and in coupled quantum well structures is described. The authors examine the validity of the simple Fabry-Perot model in describing the electron transport in actual DB diodes. They then describe a picosecond laser study to clarify the dynamics of resonant tunneling, including the intrinsic time delay associated with the multiple reflection of electron waves. Lastly, they discuss both the current state and prospects of device applications for high-speed electronics and optoelectronics     

Simple analysis of carrier transport and buildup in separateconfinement heterostructure quantum well lasers

A simple, analytical model for carrier transport and buildup in the separate confinement layer of a quantum well laser is developed. The time constant characterizing the low-frequency roll-off is separated into components describing electron and hole transport and components related to the charge storage effects arising from electron and hole capture. In contrast to previous work, the analysis shows that both the transport and capture related delays are sensitive to the placement of the well within the separate confinement heterostructure and that the carrier concentrations change abruptly across the quantum well     

生长材料中掺杂杂质纵向分布的扩散生长理论

从ＭＯＣＶＤ和卤化物ＶＰＥ的生长装置出发，分析了量子阱激光材料和微波电子材料中引入杂质的纵向分布和谐过程。采用了掺入杂质分子经载体气体漂移扩散输运和生长过程中再扩散的数学物理理论，导出了掺杂杂质最终纵向浓度分布的数学定量解析式。根据本理论，提出了陡峭掺杂和均匀纵向浓度分布的工艺解决方案。     

Diffusion Growth Model of Doping—impurity Longitudinal Profile in Grown Material by MOCVD and Chloride VPE

The program process of the longitudinal impurity profile introduced in the quantum well(QW)laser and microwave electronic materials in analysed,based on the growth system by metalorganic chemical vapor deposition(MOCVD)and microwave electronic materials and chloride vapor phase epitaxy(VPE).The quantitative solution of the final longitudinal direction impurity distribution using the mathematical physics model of impurity carrier-gas transport drift and rediffusion in growth process was carried out.A technology for giving a reference to grown imputity profile of abrupt doping and uniform longitudinal direction based on the theory is presented.     

AlGaInAs/InP应变补偿多量子阱激光器

为了优化在长距离光纤通讯系统中采用的1.31μm波长的量子阱激光器,对AlGaInAs/InP材料的有源区应变补偿的量子阱激光器进行了设计研究。采用应变补偿的方法,根据克龙尼克-潘纳模型理论计算出量子阱的能带结构,设计出有源区由1.12%的压应变AlGaInAs阱层和0.4%的张应变AlGaInAs垒层构成。使用ALDS软件对所设计出的器件进行了建模仿真,对其进行了阈值分析和稳态分析。结果表明,在室温25℃下,该激光器具有9mA的低阈值电流和0.4W/A较高的单面斜率效率;在势垒层采用与势阱层应变相反的适当应变,可以降低生长过程中的平均应变量,保证有源区良好的生长,改善量子阱结构的能带结构,提高对载流子的限制能力,降低阈值电流,提高饱和功率,改善器件的性能。     

Nonlinear analysis of quantum-well lasers with the effects ofcarrier transport

An improved nonlinear quantum-well (QW) laser model, which takes into account the effects of quantum capture and escape processes, is presented, based on laser rate equations and Volterra theory. This model is further expanded by proper parameter transform to include the effect of carrier diffusion in the separate confinement heterostructure region. Various QW laser distortions have been evaluated using this model and compared with the results obtained from the previous model where the transport effects are absent. The results shows that the effect of transport processes on laser dynamic nonlinearity can be significant     

Gain in injection lasers based on self-organized quantum dots

The analytical form of the dependence of the gain on pump current density for lasers with an active region based on self-organized quantum dots is derived in a simple theoretical model. The proposed model is shown to faithfully describe experimental data obtained for laser diodes based on InGaAs quantum dots in an AlGaAs/GaAs matrix, as well as InAs quantum dots in an InGaAs/InP matrix. The previously observed gain saturation and switching of the lasing from the ground state to an excited state of the quantum dots are studied. The influence of the density of quantum-dot arrays on the threshold characteristics of lasers based on them is examined on the basis of this model. Fiz. Tekh. Poluprovodn. 33, 215–223 (February 1999)     

Transport solutions for the SCH quantum-well laser diode

The current-voltage relations for the barrier regions in the SCH quantum well laser diode are derived in general terms under the assumption of charge neutrality. The boundary conditions are established at the quantum well SCH region interface by the clamping of the Fermi levels in the quantum well above threshold. It is shown that the current flow is comprised of opposing drift and diffusion flows with drift slightly in excess of diffusion. The recombination current in the SCH region has contributions from both drift and diffusion mechanisms. Expressions are also derived to determine the resistance and capacitance associated with the SCH transport. The appropriate small-signal current versus small-signal Fermi level dependence is specified for application to the small-signal laser response formulation