title: Frequency conversion with nonlinear graphene photodetectors.
abstract: Frequency conversion with nonlinear electronic components, a common approach for signal processing required in various communication applications, has found its operation bandwidth bottleneck due to the limited carrier mobility of the traditional materials. Meanwhile, fiber-optics communications are playing a significant role in communication services due to their excellent signal transmission properties. However, the transmitted optical signals had to be converted to electrical signals with photodetectors before frequency conversion was performed through conventional electronic devices, which make this conversion system very complex and costly. Hence, to develop a compact device that can achieve the photodetection and frequency conversion functions simultaneously is critical and significative. Here, we have proposed a novel concept for frequency conversion and demonstrated a nonlinear graphene photodetector based frequency converter that performs frequency conversion from optical signals directly. With this new concept, a frequency doubling signal at 4 GHz was obtained from a 2 GHz intensity-modulated optical signal. Moreover, using a 10 MHz intensity-modulated optical signal and another 3 GHz intensity-modulated optical signal, we show the frequency up-conversion to 3 ± 0.01 GHz. In particular, the frequency down-conversion to 100 MHz was achieved successfully by using a 2 GHz intensity-modulated optical signal and another 2.1 GHz intensity-modulated optical signal. Considering the broadband optical absorption, strong saturable absorption, high carrier mobility, and short photogenerated carrier lifetime of the graphene material, graphene photodetectors have the potential to achieve the frequency conversion of millimeter-wave band, which will open promising prospects in the domain of microwave photonics for next-gen communication systems.
authors.affiliation: State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing, 100083, PR China. bjhuang@semi.ac.cn and State Key Laboratory of Low-Dimensional Quantum Physics and Center for Atomic and Molecular Nanoscience, Department of Physics, Tsinghua University, Beijing, 10084, PR China.
authors.forename: Chuantong
authors.identifier: http://orcid.org/0000-0002-6130-5524
authors.initials: C
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing, 100083, PR China. bjhuang@semi.ac.cn.
authors.forename: Beiju
authors.initials: B
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing, 100083, PR China. bjhuang@semi.ac.cn.
authors.forename: Xurui
authors.initials: X
authors.lastname: Mao
authors.affiliation: School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin 300387, PR China.
authors.forename: Zanyun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Electronic and Control Engineering, Chang'an University, Xi'an 710064, PR China.
authors.forename: Zan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing, 100083, PR China. bjhuang@semi.ac.cn.
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Geng
authors.affiliation: State Key Laboratory of Low-Dimensional Quantum Physics and Center for Atomic and Molecular Nanoscience, Department of Physics, Tsinghua University, Beijing, 10084, PR China and Collaborative Innovation Center of Quantum Matter, Beijing, 100084, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences, Beijing, 100083, PR China. bjhuang@semi.ac.cn.
authors.forename: Hongda
authors.initials: H
authors.lastname: Chen