High-performance compact vertical germanium photodiodes enabled by silicon corner reflectors  

作　　者：WEI CHEN YANG SHI YILUN WANG MINGJIE ZOU WEN ZHANG YU YU XINLIANG ZHANG 

机构地区：[1]Wuhan National Laboratory for Optoelectronics&School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,China [2]Wuhan HG Genuine Optics Co.,Ltd.,Wuhan 430074,China [3]Optics Valley Laboratory,Wuhan 430074,China [4]Xidian University,Xi’an 710126,China

出　　处：《Photonics Research》2024年第12期2983-2988,共6页光子学研究(英文版)

基　　金：National Key Research and Development Program of China(2022YFA1404001);National Natural Science Foundation of China(61927817,62135004);China Postdoctoral Science Foundation(BX20220123).

摘　　要：High-performance germanium photodiodes are critical components in silicon photonic systems for high-capacity data communications.By reducing the length of the photodiodes,a smaller resistance–capacitance product can be achieved,leading to a larger bandwidth and lower dark current.However,this also leads to diminished responsivity due to insufficient light absorption.Here,we introduce a silicon corner reflector(SCR)to alleviate this issue by reflecting and recycling the unabsorbed light.The process of evanescent coupling between the silicon and germanium layers is elaborately engineered to optimize the efficiency of light absorption.Experimentally,a responsivity of 0.96 A/W,which is a 21%increase compared to the one without SCR,is achieved at 1550 nm with a germanium length of 4.8μm.Simultaneously,a remarkably low dark current of 0.76 nA and a large bandwidth of 100 GHz are achieved.Open eye diagrams of 140 Gb/s on–off keying and 240 Gb/s four-level pulse amplitude signals are obtained.To the best of our knowledge,this work achieves the lowest dark current density and noise equivalent power to date and offers a promising solution for low-cost,high-performance optical detection.

关 键 词：performance CAPACITANCE CORNER 

分 类 号：TN31[电子电信—物理电子学] TN15