Frequency Doubling in Femtosecond-Written Periodically-Poled Potassium Titanyl Phosphate Waveguides

Frequency doubling is demonstrated in femtosecond-laser-created single-mode waveguides written in a periodically-poled potassium titanyl phosphate crystal. Conversion efficiencies of 0.22%/W (0.02%/W) were obtained for first (third) order phasematching at 980 nm (800 nm).