Efficient type I blue second-harmonic generation in periodically segmented KTiOPO4 waveguides

We report type I phase-matched blue second-harmonic generation from periodically segmented channel ion-exchanged waveguides in KTiOPO4 with output wavelengths from 0.38 to 0.48 μm and efficiencies exceeding 50%/W cm2. Evidence is presented suggesting that these efficiencies result from ferroelectric domain reversals induced by waveguide fabrication. Waveguide structure, wavelength, and output power characteristics are presented.