Silicon-based plasmonic waveguides show high confinement
well beyond the diffraction limit. Various devices
have been demonstrated to outperform their dielectric
counterparts at micrometre scales, such as linear
modulators, capable of generating high field confinement
and improving device efficiency by increasing
access to nonlinear processes, limited by ohmic
losses. By using hybridised plasmonic waveguide architectures
and nonlinear materials, silicon-based plasmonic
waveguides can generate strong nonlinear effects
over just a few wavelengths. We have theoretically
investigated the nonlinear optical performance of two
hybrid plasmonic waveguides (HPWG) with three different
nonlinear materials. Based on this analysis, the
hybrid gap plasmon waveguide (HGPW), combined
with the DDMEBT nonlinear polymer, shows a fourwave
mixing (FWM) conversion efficiency of 16.4dB
over a 1mm propagation length, demonstrating that plasmonic
waveguides can be competitive with standard
silicon photonics structures over distances three orders
of magnitude shorter.