Xia, Guangrui (The University of British Columbia)

Purpose

With sustained exponential growth, global internet traffic is expected to reach 2.3 zettabytes (2.3x2 70 ) by 2020 [2016 Cisco]. However, mainstream short-reach communications and on-chip interconnects have been dominated by metal wires, which are much slower, less energy efficient and hard to scale in size. Optical interconnections via silicon (Si) photonics have been widely recognized as a potential solution to overcome this bottleneck. Germanium (Ge) as the most Si-compatible semiconductor has been the underlying and enabling material for Si photonics. Ge has been widely used in photodetectors and modulators providing a data rate of > 50 Gbps [2015 Chen, 2016 Srinivasan]. For Si-compatible lasers, Ge can be used as 1) transition layers between lasing materials such as InGaAs and AlGaAs and Si [2012 Lee, 2016B Lin, 2016 Liu, 2016 Nakao] due to its small lattice mismatch to them and the ease of integration with Si and 2) a lasing material thanks to bandgap engineering [2010 Liu, 2012 C-A]. On the microelectronics side, Ge has been widely used in SiGe heterojunction bipolar transistors (HBTs) for applications in wireless communications.