BO-and Monolithic Quantum Dot Semiconductor Optical Amplifier on Silicon

从信息通信技术（ICT）的角度来看，21世纪的特点是对通信能力、高性能计算和云存储的需求呈爆炸式增长。在过去的几年里，全球互联网流量呈指数级增长。在这种情况下，使用现有的电气互连和交换技术传输如此大量的数据将很快达到热负载、容量、延迟和功耗方面的“瓶颈”。结合光子集成电路（PICs）的光互连和开关结构被认为是突破这一限制的最有希望的途径之一。硅光子学目前被认为是一种可靠的光子集成平台。Si Photonics的美丽源于其利用标准CMOS IC技术在单个Si芯片上集成微电子和光子学的能力。该领域的一个重要子集是III-V在Si上的异质集成，其目的是利用具有优越光学性能的III-V材料，提供一种有效的光增益介质，以绕过Si的基本物理限制，即Si不能有效发光，同时保持Si的光路由，调制，检测能力和成本优势。在一项突破性的发展中，伦敦大学学院的研究小组已经证明，直接在Si衬底上生长外延高性能量子点（QD）激光器是可能的，从而开辟了在Si上单片集成各种类型的III-V光电子器件的可能性。单片III-V/Si集成的研究步伐随后大大加快，越来越多的著名研究小组，包括UCSB的Bowers小组和东京大学的Arakawa小组，以及主要的Si芯片公司，即英特尔，目前正在投入相当多的项目在这一领域。除了III-V/Si激光器外，单片III-V/Si半导体光放大器（soa）作为下一代光子集成光互连和交换结构的关键组件也引起了人们的极大兴趣，因为soa的应用不仅限于补偿损耗和维持信号水平，因为信号在pic内的大量光学元件中传播。它也被用作光开关的成熟门控元件，具有易于控制，占地面积小，工作电压低，开/关消光比高，以及数量级为纳秒的快速转换时间等优点。然而，这样的III-V/Si SOA到目前为止还没有开发出来。基于UCL在单片III-V/Si QD激光器方面的专业知识，该项目提案旨在开发世界上第一个基于cmos兼容的轴上Si（001）衬底的单片III-V QD SOA。与传统的基于本地衬底的soa或使用倒装片键合或晶圆键合的III-V/Si soa相比，所提出的方法具有根本的不同，因为III-V soa将通过直接外延方法集成在Si上，提供了实现高产量，低成本和大规模Si基pic的可能性，这有望成为解决下一代光互连和开关解决方案的技术平台。随着硅光子学的进一步发展，即为微电子世界提供光子元件的超大规模集成，将有机会在消费电子、高性能计算、医疗和传感器解决方案以及国防等重要领域实现目标应用。该项目将受益于工业和学术合作伙伴的指导和联合工作，并将利用英国在材料（例如CSC， EPSRC NEF）设备加工（例如EPSRC CSHub，格拉斯哥）和光子学（例如Rockley， Lumentum）方面的主要工业和学术优势，他们也很好地利用了这项研究。

From an Information and Communication Technology (ICT) perspective, the 21st century is characterized by an explosion of requests for communication capabilities, high-performance computing, and cloud storage. Over the last few years, global Internet traffic has been growing exponentially. In this picture, transporting such an amount of data with existing electrical- interconnects and switching technologies will soon reach the "bottleneck" in terms of thermal loading, capacity, latency and power consumption. Optical- interconnects and switch fabrics combined with photonic integrated circuits (PICs) are seen as one of the most promising routes to push such limits. Silicon (Si) photonics is now considered as a reliable photonic integration platform. The beauty of Si Photonics stems from its ability to integrate microelectronics and photonics on a single Si chip utilizing standard CMOS IC technology. An important subset of this area is hetero-integration of III-Vs on Si, where the aim is the make use of III-V materials, with superior optical properties, to provide an efficient optical gain medium to circumvent the fundamental physical limitation of Si, i.e. Si cannot efficiently emit light, yet keeping the capability of light-routing, modulating, detecting and cost advantages of Si. In a breakthrough development, the investigators' group in UCL have shown that it is possible to grow epitaxially high-performance quantum dot (QD) lasers directly on Si substrates, opening up the possibility to monolithically integrate various types of III-V optoelectronic devices on Si. The pace of research on monolithic III-V/Si integration has then been dramatically accelerated and an increasing number of prestigious research groups including Bowers' group at UCSB and Arakawa's group at Tokyo University, and major Si chip companies, i.e. Intel, are currently devoting considerable programmes in this area. In addition to III-V/Si lasers, monolithic III-V/Si semiconductor optical amplifiers (SOAs) are also attracting significant interest as the key components for next-generation photonic integrated optical- interconnects and switching fabrics, as the application of SOAs is not limited only to compensate for loss and maintain signal levels as the signal propagates throughout a large number of optical components within the PICs, it is also used as a mature gating element for optical switches and has the advantages of ease of control, smaller footprint, low operating voltage, high ON/OFF extinction ratio, and fast transition times of the order of nanoseconds. However, such a III-V/Si SOA has not been developed to date. Building on the established expertise in monolithic III-V/Si QD lasers at UCL, this project proposal aims to develop the world's first monolithic III-V QD SOA on CMOS-compatible on-axis Si (001) substrates. In contrast to conventional native substrate based SOAs or III-V/Si SOAs using either flip-chip bonding or wafer bonding, the proposed method is fundamentally different, since the III-V SOAs will be integrated on Si by direct epitaxial methods, offering the possibility to achieve high-yield, low-cost and large-scale Si-based PICs, which is expected to be the technology platform to address next-generation optical- interconnect and switching solutions. With further development in Si photonics, i.e., providing the microelectronics world with the ultra-large-scale integration of photonic components, there will be scope to target applications in important areas such as consumer electronics, high-performance computing, medical and sensor solutions, and defence. This project will benefit from guidance from and joint work with both industrial as well as academic partners and will leverage major UK-based industrial and academic strengths in materials (e.g., CSC, EPSRC NEF) device processing (e.g., EPSRC CSHub, Glasgow) and photonics (e.g., Rockley, Lumentum), who are also well positioned to exploit this research.