Kerr effect in hybrid plasmonic waveguides

Hybrid plasmonic waveguides, in which light is guided by a combination of dielectric and plasmonic confinement, are likely to play a key role in compact nonlinear optical devices. Although their absorption loss is considerable, through a small device footprint and careful optimization, a significant nonlinear phase shift may be achieved. Here, we study the Kerr effect in hybrid plasmonic waveguides by analyzing the modal effective area, energy velocity, absorption loss, and a weighted average of the constituents' nonlinear refractive indices to gain physical insight into its behavior. We pinpoint the nonlinear contribution as the predominant factor in achieving a large third-order susceptibility and discuss its limitations. By providing a deep understanding of hybrid plasmonic waveguides for nonlinear applications, we indicate pathways for their future optimization.