An Antimonide Strained Quantum Well Laser Operating at Lambda > Micrometer

这个小型企业创新研究第一阶段项目将展示利用分子束外延技术开发激光二极管的可行性，使用InGaAsSb/AlGaAsSb应变量子阱(QW)结构，工作在中红外(MIR)范围(6？m)。我们的MIR激光器结构的开发服务于多种两用应用，可立即用于分子光谱、遥感以及光纤通信和激光雷达系统。发射波长可扩展到6？m范围。结构材料工业公司的S激光二极管由三个区域组成。中间是有源区，未掺杂的AlGaAsSb层限制了InGaAsSb量子点。有源区被两个重掺杂的AlGaAsSb包层夹在中间，形成了pn结，提供了光学限制。在第一阶段，激光结构将生长在带有缓冲层的InP衬底上，AlGaAsSb层与缓冲层晶格匹配。与GaSb和InAs相比，使用带有缓冲层的InP衬底对锑化物具有优势。他们预计，与传统的基于锑的量子波或双异质结(DH)激光器相比，使用应变量子波结构将大大增加激光波长。量子阱中与量子效应相关的态密度的改变可以导致阈值电流的降低和温度敏感性的降低。他们将研究应变和量子效应以及俄歇复合过程，这是低禁带材料中重要的非辐射机制，以优化他们的激光器设计。在第一阶段，他们的设计将被实施、表征并与模型进行比较。第一阶段的工作将为第二阶段的进一步发展奠定坚实的基础。所选择的应变量子波方法将使他们能够在以后的阶段开发这种材料，覆盖从6到10？m的激光波长范围。将改进生长、加工和封装能力，并实施分布式反馈机制，以提高第二阶段单模操作的模式选择性，以生产适用于军事和商业应用的激光器。他们还将在红外光谱痕量气体浓度监测分析系统中实施激光。

This Small Business Innovation Research Phase I project will demonstrate feasibility of development of laser diodes by MBE, operating in the mid-infrared (MIR) range ((6ªm) using the InGaAsSb/AlGaAsSb strained quantum well (QW) structure. The development of our MIR laser structures serves a variety of dual-use applications having immediate use in molecular spectroscopy, remote sensing, as well as in optical fiber telecommunications and laser radar systems. The emitting wavelengths are extendible to cover the 6-ªm range. Structured Materials Industries, Inc.'s laser diode is constructed with three regions. In the middle is the active region where undoped AlGaAsSb layers confine the InGaAsSb QWs. The active region is sandwiched by two heavily doped AlGaAsSb cladding layers which form a pn junction and provides the optical confinement. In Phase 1, the laser structure will be grown InP substrates with a buffer layer to which the AlGaAsSb layers are lattice-matched. Using InP substrates with a buffer layer has demonstrated advantages over GaSb and InAs for the antimonides. They anticipate a major increase in laser wavelength by the use of strained QW structures as compared to conventional antimonide based QW or double heterostructure (DH) lasers. The modification of the density of states in QWs associated with the quantum effects can result in lower threshold current and reduced temperature sensitivity. They will study strain and quantum effects as well as the Auger recombination process, an important nonradiative mechanism in low bandgap materials, in order to optimize their laser design. In Phase I, their design will be implemented, characterized and compared to the model. The Phase I effort will create a firm base for the further development in Phase II. The strained QW approach chosen will allow them to develop this material to cover the laser wavelength range from 6 to 10ªm in later Phases. The growth, processing and packaging capability will be refined and a distributed feedback mechanism will be implemented to improve the mode selectivity for single mode operation in Phase II in order to produce lasers suitable for military and commercial applications. They will also implement the lasers in IR spectroscopic Trace Gas Concentration Monitoring and Analysis system.