LINBO3 WAVE-GUIDE QUASI-PHASE-MATCHING 2ND-HARMONIC GENERATION DEVICES WITH FERROELECTRIC-DOMAIN-INVERTED GRATINGS FORMED BY ELECTRON-BEAM SCANNING

The characteristics of the formation of LiNbO3 ferroelectric-domain-inverted gratings using electron-beam scanning were examined and discussed for application to waveguide quasi-phase-matching second-harmonic-generation (SHG) devices. It was found that the domain inversion tended to occur in segmented regions and the inversion width was thinner near the crystal surface than inside the crystal. The dependence of the SHG efficiency on the grating structure was examined theoretically. Prototype devices for green and blue light generation were fabricated and the device performance was examined. Normalized SHG efficiencies as high as 50%/W and 70%/W, respectively, were obtained in green and blue light generation devices of 3.3 mm length. The experimental results were discussed in comparison with the theoretical results.