High-performance silicon−graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm
Jingshu Guo, Jiang Li, Chaoyue Liu, Yanlong Yin, Wenhui Wang, Zhenhua Ni, Zhilei Fu, Hui Yu, Yang Xu, Yaocheng Shi, Yungui Ma, Shiming Gao, Limin Tong, Daoxin Dai
Abstract
Graphene has attracted much attention for the realization of high-speed photodetection for silicon photonics over a wide wavelength range. However, the reported fast graphene photodetectors mainly operate in the 1.55 μm wavelength band. In this work, we propose and realize high-performance waveguide photodetectors based on bolometric/photoconductive effects by introducing an ultrathin wide silicon-graphene hybrid plasmonic waveguide, which enables efficient light absorption in graphene at 1.55 μm and beyond. When operating at 2 μm, the present photodetector has a responsivity of ~70 mA/W and a setup-limited 3 dB bandwidth of >20 GHz. When operating at 1.55 μm, the present photodetector also works very well with a broad 3 dB bandwidth of >40 GHz (setup-limited) and a high responsivity of ~0.4 A/W even with a low bias voltage of -0.3 V. This work paves the way for achieving high-responsivity and high-speed silicon-graphene waveguide photodetection in the near/mid-infrared ranges, which has applications in optical communications, nonlinear photonics, and on-chip sensing.