Electric field-induced second harmonic generation in Silicon waveguide by interdigitated contacts

Second order optical nonlinearities induced in silicon waveguides by the application of an electric field are evidenced by measuring second harmonic generation (SHG) in the mid infrared. The electric field is produced by lateral p-i-n junctions which are periodically disposed across the waveguide to reach a quasi-phase matching condition. Here, we report on the modeling of the experimental results by using stochastic variations of waveguide and junction geometries which are compatible with the fabrication technique. These variations lead to a broad band multiple peaked spectrum of the SHG efficiency around the nominal phase matched wavelength. Agreement between experiments and simulations is found.