Electroabsorption modulators and laser diodes for free space optics and on-chip applications

用于自由空间光学和片上应用的电吸收调制器和激光二极管

• 批准号: 2036167
• 金额: --
• 依托单位: CARDIFF UNIVERSITY
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2036167
• 关键词: Electroabsorption; modulators; laser; diodes; free

The main objective is to design a modulator that can be fitted to an unmanned aerial vehicle (UAV) to provide an optical datalink that is fast, secure and robust. There has been a significant amount of research conducted into free space optical communication systems in the last decade alone and a modulating retro-reflector system is the best solution for a lightweight and efficient modulator. The bulk of this work has focussed on cat's eye retro-reflector (CER) systems, rather than the simpler corner-cube retro-reflector (CCR), due to limitations on size and speed that come with the larger CCR. CER systems are generally less robust than CCR due to high precision required in lens positioning, potential optical aberrations and quite severe limitations on field of view. The primary aim for this project is to utilize modern manufacturing and fabrication techniques to construct a large, pixelated electro absorption CCR modulator. Advances in manufacturing techniques have created more possibilities in type-II semiconductor systems and these will form the basis for further research, modelling and testing. Antimony based compounds show great potential for application at 1.55um wavelength. Manufacturing and fabrication developments allow for the construction of precise type-II multiple quantum well heterostructures that can be engineered to this specific use. The material system which appears to be the most applicable combines GaSb quantum wells with AlGaSb barriers. This multiple quantum well active region will then be fabricated within a P-I-N diode structure. Type-II materials have strong confinement of electrons and holes with spatial separation, thus generally holes are confined to the well material and electrons to the barrier material. This can lead to very large shifts in the optical absorption of the material when under an electrical bias. This is ideal for providing a high extinction ratio.Furthermore, by pixelating this material, high speed data transmission can be achieved without compromising the field of view of the retro-reflector. Another aim for the project is to create 'smart' pixels that will only be active upon incident light of wavelength 1.55um. This will greatly reduce the overall power consumption of the modulator. Other considerations to optimise the system will be the temperature stability of the material, contrast ratio and insertion loss. The intention is that the PhD will also characterise the performance of as-grown structures.

主要目的是设计一种可以安装在无人机上的调制器，以提供快速、安全和健壮的光学数据链路。仅在过去的十年里，人们就对自由空间光通信系统进行了大量的研究，而调制式后向反射器系统是轻量化和高效调制器的最佳解决方案。这项工作的大部分都集中在猫眼追溯反射器(CER)系统上，而不是更简单的角立方体追溯反射器(CCR)，因为较大的CCR在尺寸和速度上有限制。由于透镜定位的高精度要求、潜在的光学像差和相当严格的视场限制，CER系统通常不如CCR系统健壮。该项目的主要目标是利用现代制造和制造技术来构建一个大型的、像素化的电吸收CCR调制器。制造技术的进步为第二类半导体系统创造了更多的可能性，这些将构成进一步研究、建模和测试的基础。在1.55 nm波段，锑基化合物显示出巨大的应用潜力。制造和制造的发展使得可以建造精确的第二类多量子阱异质结构，这种异质结构可以根据这一特定用途进行工程设计。这种材料系统似乎是最适用的，它将GaSb量子阱和AlGaSb势垒结合在一起。然后，将在P-I-N二极管结构内制造该多量子阱有源区。第二类材料具有很强的电子和空穴的限制，具有空间上的分离，因此通常空穴被限制在势垒材料中，而电子被限制在势垒材料中。这会导致材料在电偏压下的光吸收发生很大的变化。这是提供高消光比的理想选择。此外，通过像素化这种材料，可以在不影响反向反射器的视场的情况下实现高速数据传输。该项目的另一个目标是创造只有在波长为1.55微米的入射光下才有效的智能像素。这将大大降低调制器的整体功耗。优化系统的其他考虑因素包括材料的温度稳定性、对比度和插入损耗。其意图是，博士学位也将表征初创结构的表现。