Experimental Demonstration of Vertical ${\rm Cu}\hbox {-}{\rm SiO}_{2}\hbox {-}{\rm Si}$ Hybrid Plasmonic Waveguide Components on an SOI Platform

Vertical Cu-SiO₂-Si hybrid plasmonic waveguides (HPWs) along with various passive components are fabricated on a silicon-on-insulator platform using standard complementary metal-oxide-semiconductor (CMOS) technology and characterized at 1550-nm telecommunication wavelengths. The HPW exhibits relatively low propagation loss of ~0.12 dB/μm and high coupling efficiency of ~86% with the conventional Si strip waveguide. A plasmonic waveguide-ring resonator with 1.09-μm radius exhibits extinction ratio of ~13.7 dB, free spectral range of ~106 nm, and Q-factor of ~63. These superior performances together with the CMOS compatibility make the HPW an attractive candidate for future dense Si nanophotonic integrated circuits.