Cost-effective Silicon Photonic Optical Engine for Inter-chip Data Connections

信息技术的快速发展对用于信号处理和计算的低成本、高密度和高速的芯片间数据连接产生了迫切的需求。与传统的电信号相比，光信号不仅可以为芯片间数据传输提供更宽的带宽和更短的时延，而且还可以提供更多的自由度（例如，极化）以用于复杂的芯片间连接拓扑。由于缺乏全光逻辑和存储单元，信号仍需要在电子域进行处理。因此，光引擎在桥接用于处理的电信号和用于传输的光信号方面是不可或缺的。硅（Si）光子学已经脱颖而出，作为托管由集成光子和光电器件和电路组成的上述光学引擎的有前途的平台，这是由于其成熟的加工技术和材料丰富性带来的成本效益，以及其支持高密度集成的可行性带来的紧凑性和鲁棒性。晶片键合方法被广泛认为是获得高性能Si光子激光器的最有前途的技术，所述Si光子激光器用作驱动整个Si光子电路的光源。然而，目前的倏逝波耦合技术的低成品率和低可靠性对大规模生产设置了主要障碍。我们提出的光栅辅助耦合方法可以避免这些问题。将类似的概念应用于光电探测器（PD），利用光栅区分相干信号和非相干噪声，可以在提高光增益的同时降低噪声，从而提高PD的灵敏度。因此，我们的光引擎技术将通过完全集成的100Gbps光收发器芯片原型来展示。我们提出的研究，如果成功的话，将解决在大规模生产的硅光子激光器的良率和可靠性问题，将大大提高硅锗PD的性能，并将因此建立芯片间数据连接的光引擎技术。通过该研究计划发明的结构、演示的器件和获得的知识不仅将促进下一代芯片间光互连技术，而且还将使相关领域的许多加拿大公司受益，自混合单片和混合集成技术成功建立以来，在多种材料平台上的结构将使得能够发明具有新的或扩展的复杂功能或增强的性能的整组先进的光子和光电器件，它将对通信和传感器网络的发展产生重大影响。该计划还将为加拿大工业产生一批高技能的研究生。

The rapid development of the information technology creates pressing needs on cost-effective, high-density, and high-speed inter-chip data connections for signal processing and computing. Comparing to the conventional electric signal, the optical signal can offer not only a much broader bandwidth and a shorter time delay for inter-chip data transmission, but also more degrees of freedom (e.g., polarization) for complex inter-chip connection topology. Due to the lack of all optical logic and memory units, the signal still needs to be processed in electronic domain. Optical engines are therefore indispensable in bridging the electric signal for processing and the optical signal for transmission. Silicon (Si) photonics has stood out as a promising platform of hosting the aforementioned optical engine comprised of integrated photonic and optoelectronic devices and circuits, due to its cost-effectiveness originated from its matured processing techniques and material abundance, and its compactness and robustness attributed to its viability of supporting high-density integration. The wafer-bonding approach is widely accepted as the most promising technology to obtain high performance Si photonic lasers that serve as the light source to drive the entire Si photonic circuits. However, the low yield and reliability of current evanescent wave coupling technology sets a major hurdle to mass production. Our proposed grating assistant coupling method can avoid these problems. By applying the similar concept to the photo-detector (PD), we can boost the optical gain and reduced the noise simultaneously by exploiting the grating to discriminate the coherent signal and non-coherent noise, thereby to raise the sensitivity of the PD. Consequently, our optical engine technology will be demonstrated by a fully integrated 100Gbps optical transceiver chip prototype. Our proposed research, if successful, will solve the yield and reliability issues in mass production of Si photonic lasers, will greatly raise the performance of Si-Ge PDs, and will consequently establish the optical engine technology for inter-chip data connection. The structure invented, device demonstrated, and knowledge acquired through this research program will not only prompt the next generation optical interconnection technology at the inter-chip level, but will also benefit a number of Canadian companies in relevant areas, since the successful establishment of the mixed monolithic and hybrid integration technology for hetero-structures on multiple material platforms will enable the invention of an entire group of advanced photonic and optoelectronic devices with new or extended complex functions or enhanced performance, it will have significant impact on the development of communication and senor networks. The program will also generate a stream of highly skilled graduate students for Canadian industry.