Nonlinear plasmonic waveguides

Recent results on plasmonic waveguides are summarized. After a brief introduction to motivate the use of plasmonic structures for optical integrated devices and to present the main characteristics and potential applications, the metal-dielectric-metal slot waveguide is studied. The way to calculate the complex modes, which are necessary for a proper modeling taking optical losses into account, is presented for the linear and nonlinear cases. This calculations are then used to obtain the dispersion curves and to show the way modes transform when losses go from negligible to realistic values. The calculation of nonlinear modes leads to the study of the power dispersion curves considering optical losses and to the comparison with the non lossy case. Also, the way to simulate the propagation of light in this structures, using the finite-difference time-domain technique is discussed. The last part of the text deals with specific devices: nonlinear directional couplers applied to optical power switching. Finally, the use of tapered waveguides for the directional coupler is proposed, as a way to avoid the negative effect of optical loss and to enhance the coupler performance.