RIA: Novel Electroabsorption in Stained-Layer Hetero- structures A New Effect with Potential Applications in Optoelectronics Devices

光电光调制器，即通过其 光的透射可以通过改变所施加的光的透射率来调制。 控制电压，对于其中电子 需要控制被引导的光波（例如光纤 通信系统）。 目前最先进的 器件是多量子阱（MQW）波导调制器， 利用了一种称为量子限制的电吸收效应， 斯塔克效应（QCSE）。 MQW调制器的显著改进 然而，通过利用 本文提出的电吸收增强机制称为 场诱导吸收边混合（AEM）效应。 独特的 实现这种效应所需的价带配置是 仅在某些类型的应变层异质结构中可用， 在电吸收研究中尚未考虑。 详细 对迄今尚未探索的AEM效应的研究是 这个提议。 场相关近带吸收的理论模型 特性将首先被开发并用于设计最佳 最大化AEM效果。 合适的应变层多量子阱 然后通过金属有机化学气相生长结构， 沉积（MOCVD），使用低温发光评估 技术，并用于制造测试结构。 示范 然后将尝试AEM效应，如果观察到， 将进一步表征其在光学领域的潜在用途， 评估调节剂。 在合理的温度下观察大型AEM效应 控制电压-这似乎是有前途的基础上， 本建议中所述的考虑因素-可能导致 现有MQW波导调制器的改进以及新的MQW波导调制器 光电器件，如压控偏振器。

Optoelectronic light modulators, i.e. devices through which the transmission of light may be modulated by variation of an applied control voltage, are of interest for applications in which electronic control of guided light waves is required (e.g. fiber-optic commlunications systems). The current state-of-the-art in such devices is the multiple-quantum-well (MQW) waveguide modulator, which makes use of an electroabsorption effect called the quantum-confined Stark effect (QCSE). Significant improvements in MQW modulator performance may be possible, however, by exploiting an electroabsorption enhancement mechanism proposed here and termed the "field-induced absorption-edge mixing" (AEM) effect. The unique valence-band configuration required to achieve this effect is available only in certain types strained-layer heterostructures which have not yet been considered in electroabsorption studies. A detailed investigation of the hitherto unexplored AEM effect is the topic of this proposal. Theoretical models of the field-dependent near-gap absorption characteristics will first be developed and used to design optimum structures for maximum AEM effect. Appropriate strained-layer MQW structures will then be grown by metalorganic chemical vapor deposition (MOCVD), evaluated using low-temperature luminescence techniques, and used to fabricate test structures. Demonstration of the AEM effect will then be attempted and, if observed, the effect will be further characterized and its potential usefulness in optical modulators assessed. Observation large AEM effects at reasonable control voltages - which seems promising based on fundamental considerations described in this proposal - could lead both to improvements in existing MQW waveguide modulators and to new optoelectronic devices such as voltage-controlled polarizers as well.