Optimization Of Second Harmonic Generation And Nonlinear Phase-Shifts In The Čerenkov Regime

We present Beam Propagation Method (BPM) studies of Second Harmonic Generation (SHG) and nonlinear phase-shifts by cascading. The studies concentrate on SHG by means of radiation modes; the Čerenkov regime. The presented modeling does take into account both depletion and nonlinear phase shifts of the fundamental fields. BPM results show that leaky waves play an important role offering possibilities for enhancing the efficiency of SHG by orders of magnitude over general Čerenkov processes. Using a simple model and taking into account symmetry considerations, we identify the leaky modes that are important for the χ(2)-processes in the structures that we investigated