Effects of interference in quasiphase-matched periodically segmented potassium titanyl phosphate waveguides

Abstract

We show that optical interference of two input beams coupled into a periodically segmented KTiOPO4 waveguide can increase the efficiency of the generated second harmonic by a factor of three over coupling a single beam with the same total power. A simple model based on two interfering Gaussian beams indicates that the second harmonic output increases by enhancing the coupling of the fundamental energy into the waveguide. A Mach-Zehnder interferometer scheme is used to demonstrate this effect. The variation of the second harmonic power with the fundamental input power of the interfering beams shows excellent qualitative agreement between experimental results and the model presented. © 1999 American Institute of Physics.