A hybrid plasmonic waveguide consisting of a thin high-index dielectric stripe embedded inside the gap between a metallic substrate and a semiconductor ridge is presented for the purpose of enhanced optical confinement in the gap. By engineering the key geometrical parameters of the stripe, both of the power ratios resided inside the whole gap and the silicon ridge can be enhanced greatly. A power confinement ratio as large as 0.54 in the overall gap region is achievable, for a structure with a 200 nm-wide, 90 nm-thick silicon-stripe embedded in the center of a 100 nm-thick silica gap, which is nearly 50% improvement over that of the corresponding conventional hybrid waveguide. Meanwhile, with the introduction of the 90 nm-thick silicon stripe, the effective mode area of the waveguide exhibits a reduction of 50%-60% with a reasonable propagation length around 25-65 μm for different stripe widths. A study on the influence of possible fabrication imperfections reveals that the modal property is quite robust and highly tolerant to these errors. Such a hybrid plasmonic waveguide with enhanced optical confinement and moderate modal loss may enable the realization of ultra-compact passive components, nanolasers with low pumping thresholds, and other potential applications.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- integrated photonics
- surface plasmon