Silicon Photonics for Microwave Photonics Applications

微波光子学是用光子学的方法研究微波与光波相互作用以产生、处理、控制和分配微波信号的领域，在宽带无线通信、雷达、传感器、成像和现代仪器等领域有着广泛的应用。将光子学用于微波应用的主要动机是光子学提供的大带宽和低损耗，这使得某些重要功能的实现成为可能，而在电学领域，同样的功能可能无法实现，或者系统变得极其复杂和昂贵。在过去的几年里，已经提出并展示了不同的微波光子学系统。然而，这些系统主要是基于分立的光子和微波器件实现的，这使得系统体积大、重量重、成本高，性能相对较差。另一方面，在过去的几年里，人们对在硅芯片上集成光子器件的兴趣越来越大，这一领域被称为硅光子学。与基于III-V半导体的传统光子器件相比，硅光子学是一种允许使用标准和成熟的半导体制造技术来经济地制造光学器件的技术。在过去的几年里，在硅衬底上实现无源和有源光学器件方面取得了重大突破，如光波导、滤光器、分插复用器、调制器和光电探测器。然而，很少有关于实现基于硅光子学的微波光子学器件和系统的演示报道。这项研究的目的是利用成熟的硅集成技术在绝缘体上硅(SOI)衬底上制造微波光子器件和系统，以展示不同的微波光子学功能，并显著提高系统性能。

Microwave photonics is an area that studies the interaction between microwave and optical waves for the generation, processing, control and distribution of microwave signals by means of photonics,which can find numerous applications such as broadband wireless communications, radar, sensors, imaging, and modern instrumentation. The key motivation of using photonics for microwave applications is the large bandwidth and low loss offered by photonics, which makes the implementation of certain important functions possible while in the electrical domain the same functions may not be realizable or the systems become extremely complicated and costly. Different microwave photonics systems have been proposed and demonstrated in the past few years. However, these systems were implemented mainly based on discrete photonic and microwave components, which make the systems bulky, heavy and costly with relatively poorer performance. On the other hand, there is an increasing interest in the last few years in integrating photonic devices on silicon chips, an area called silicon photonics. Compared to conventional photonic devices based on III-V semiconductors, silicon photonics is a technique that allows optical devices to be made economically using standard and well-developed semiconductor fabrication techniques. Significant breakthroughs have been made in the last few years in implementing both passive and active optical devices on a silicon substrate, such as optical waveguides, optical filters, add-drop multiplexers, modulators, and photodetectors. However, very few demonstrations have been reported to implement microwave photonics devices and systems based on silicon photonics. The motivation of the proposed research is to use the well-established silicon integration technologies to fabricate microwave photonic devices and systems on a silicon-on-insulator (SOI) substrate, to demonstrate different microwave photonics functionalities with significantly improved system performance.