基于纳米尺度高折射率差亚波长光栅的硅基宽光谱增强型集成光探测器研究

With the rapid development of high-speed optical communication system and networks, more demanding requirements are imposed on the optoelectronic devices. Silicon based optoelectronic integrated devices with novel micro-nano structures have become one of the important development trends for the high-speed optoelectronic devices. As novel micro-nano structures, subwavelength gratings used in high-performance optoelectronic devices, are attracting a lot of attention. When the period of subwavelength gratings are at the scale of nanometer, and employing special patterns or even asymmetric structures, new optical phenomena and physical laws will emerge. Study on this subject will contribute to developing of high-performance optoelectronic devices and push forward the device renovation and promotion in multiple fields including high-speed optical communication and optical networks.This project focus on the basic science studies on control of optical fields, such as light reflection, transmission, polarization, convergence, by using nanoscale high-contrast subwavelength gratings. Furthermore, it will be studied that Si-based subwavelength gratings applied in high-speed broad-band integrated photodetectors. We hope that, incorporating novel nanoscale structures, the device will be easy to be integrated, obtain high speed as well as achieve high quantum efficiency within the whole long wavelength range of optical communication. Based on silicon-on-insulator (SOI) substrate, the nanoscale subwavelength gratings are accomplished with high-contrast which are compatible with standard CMOS technology. Based on subwavelength gratings' characteristics of high reflectivity in a broad spectrum range, high quantum efficiency as well as wide spectral response can be achieved. Moreover, taking advantages of light convergence characteristics of subwavelength gratings, the p-i-n photodetectors with mushroom-like structure are designed to enhance the frequency response. The studies of the project will provide guidelines and basis for the research on the further optoelectronic integrated devices based on novel structures, techniques or materials.

高速光通信系统和网络的飞速发展对光电子器件性能提出了更高的要求，基于新型微纳结构的硅基光子集成器件已经成为高速光电子器件发展的必然趋势之一。亚波长光栅作为一种新型微纳结构，应用于高性能光电子器件的研究开始得到人们极大的关注，特别是当亚波长光栅结构进入纳米尺度，采用特殊图案，甚至非对称结构时，会产生新的光学现象和物理规律。针对这一课题的研究将有助于高性能光电子器件的发展，并推动包括高速光通信、光网络在内的多领域器件的革新与升级。项目主要研究基于纳米尺度的高折射率差亚波长光栅实现光反射、透射、偏振和会聚的基础科学问题，以及硅基亚波长光栅在高速宽光谱增强型集成光探测器中的应用。希望借助纳米尺度新型微纳结构，使器件具有易于集成，高响应带宽，同时在长波长通信波段宽光谱范围内实现高量子效率的特点。本项目的研究工作将为基于新结构、新工艺、新材料的新型光电子集成器件研究提供基础和思路。

新一代高速光通信技术的飞速发展，对光电子器件性能的要求进一步提升。基于新型微纳结构的高性能光电子集成器件成为高速光电子器件发展的必然趋势之一。高折射率差亚波长光栅作为一种新型微纳结构，在集成光电子器件中的应用，逐步得到人们的关注。本项目设计并制备了基于高折射率差亚波长光栅的硅基宽光谱增强型集成光探测器。希望通过器件结构和工艺的创新，解决垂直型光探测器频率响应和量子效率的固有矛盾，使两者同时提高。.项目组成功制备了基于高折射率差亚波长的一维光栅、二维光栅和环形光栅；实现了非周期光栅对光聚焦和偏振特性的调控；构建了基于微纳尺度功能结构的光电子集成器件的设计方法；在此基础上，提出并实现了两种新颖的用于光通信波段的光探测器：一种是亚波长光栅反射增强型宽光谱光探测器。另一种是基于亚波长光栅的蘑菇型光探测器。在项目研究过程中形成了完善的理论分析方法与较为成熟的关键器件工艺。项目的实施为高性能垂直型光探测器研发和产业化奠定了基础。.项目取得的研究成果包括：.1、提出具有汇聚功能的SOI基环形非周期亚波长光栅结构和偏振不敏感二维非周期亚波长光栅结构。两种器件的焦距都为6μm，在1.55μm处反射率全部大于82%。.2、提出并制备亚波长光栅反射增强型宽光谱光探测器，实现了同心环形亚波长光栅与InGaAs/InP光探测器结构的集成。集成器件的量子效率提高27.5%。在3V反向偏压下，具有CC-SWGs结构的光探测器在1.55μm波长处量子效率达到65%，频率响应3dB带宽达到40GHz。.3、提出并制备基于亚波长光栅的蘑菇型光探测器。实现了同心环形亚波长汇聚光栅与InGaAs/InP蘑菇型光探测器结构的集成。量子效率提升21.4%，3dB带宽达到30GHz；实现了二维亚波长汇聚光栅与InGaAs/InP蘑菇型光探测器结构的集成，器件偏振不敏感，量子效率提升约25%，3dB带宽超过40GHz。.项目在理论和实验方面均取得突破性成果，在国内知名外学术刊物上发表SCI收录论文20篇，包括Opt Lett、Opt Express、Appl. Phys. Lett.等国际著名学术期刊；授权发明专利3项，申请专利5项；培养博士4人，硕士7人。