Novel hybrid plasmonic-based directional coupler on InP substrate

A novel hybrid plasmonic waveguide with a layer stack of Au/InP/InGaAsP on InP substrate was described in this study. Previously, the layer stack was utilized to fabricate all passive and active conventional photonic integrated circuits. It has been demonstrated that the optical field will be confined in the interface of InP/Au at the optical communication wavelength of 1550 nm. The propagation length in the proposed hybrid plasmonic waveguide is over 20 μm. A directional coupler was also investigated using the present layer structure, which shows a minimum coupling length of 2 μm.