Reconfigurable parametric amplifications of spoof surface plasmons

• Main Authors: Gao, Xinxin, Zhang, Jingjing, Luo, Yu, Ma, Qian, Bai, Guo Dong, Zhang, Hao Chi, Cui, Tie Jun
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Engineering::Electrical and electronic engineering; Phase-Matching Conditions; Reconfigurable Parametric Amplifier
• Online Access: https://hdl.handle.net/10356/153790
• Institution: Nanyang Technological University

Next-generation inter-chip communication requires ultrafast ultra-compact interconnects. Designer plasmonics offers a possible route towards this goal. Further development of the plasmonic technique to circuit applications requires the direct amplification of plasmonic signals on a compact platform. However, significant signal distortions and limited operational speeds prevent the application of traditional MOS-based amplifiers to plasmonics. Up to day, the amplification of surface plasmons without phase distortion has remained a scientific challenge. In this work, the concept of parametric amplification (PA) is transplanted to the plasmonics and is realized experimentally an ultrathin reconfigurable PA using a spoof surface plasmon polariton (SSPP) waveguide integrated with tunable and nonlinear varactors. The measured parametric gain in the experiment can reach up to 9.14 dB within a short nonlinear propagation length, for example, six SSPP wavelengths, in excellent agreement with the theoretical prediction. By tuning the bias voltage of varactors, the phase-matching condition can be precisely controlled over a broad frequency band, enabling the authors to realize the multi-frequency PA of plasmonic signals. Measured phase responses confirm that the plasmonic parametric amplifier can significantly suppress the signal distortions as compared with the traditional MOS-based amplifier, which is a property highly desired for ultrafast wireless communication systems and integrated circuits.