Switching and second harmonic generation using counterpropagating quasi-phase-matching in a mirrorless configuration

Numerical solutions to the set of coupled nonlinear wave equations for a novel mirrorless counterpropagating quasi-phase-matched (c-QPM) device are presented. Mirrorless c-QPM is investigated in stand-alone and in two interferometric configurations for all-optical switching (AOS) applications. The switching intensity is found to be very low using existing materials (e.g., 500 mW in a 1-cm-long KTP waveguide with a 10 μm² effective area). Additionally, parameter sets are found that minimize pulse breakup and improve the possibility of a practical implementation. Although second harmonic generation (SHG) is also investigated in the stand-alone device, the conversion efficiency is shown to be eight times less efficient than the mirrored configuration