Quasi-phase-matched second-harmonic generation is observed in an AlGaAs waveguide. The AlGaAs waveguide is epitaxially grown on a template substrate where a periodic crystal domain inversion is achieved using wafer bonding and organometallic chemical vapor deposition. A scanning electron micrograph of the waveguide cross section reveals a distinct propagation of the crystal domain boundaries in the epitaxial growth direction. Second-harmonic generation measurements on a fabricated rib-loaded waveguide show a clear quadratic dependence of the second-harmonic power to the input fundamental power. The peak conversion efficiency is 4.9%/W whereas the theoretical value is 124%/W for an ideal waveguide with no loss and with equal domain dimensions. A significant increase in the conversion efficiency is expected with reduced scattering losses realized by improved epitaxial growth and fabrication processes.

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We have developed roll printing process for low cost TFT LCD fabrication. Pattern position accuracy which is the most important issue for successful printing process could be improved by remodeling the blanket structure and the physical property of PDMS. Through improving printing pattern accuracy, we were able to print all layers of TFT and CF on substrates and a 15 inch XGA TFT LCD panel adopting TN mode was successfully fabricated.

We have analyzed a metal direct printing method using roll printing technology for the low cost process in TFT‐LCD fabrication. The silver metal electrodes patterned down to 3 μm in space width between lines were directly printed by this method. Very low line resistivity of 4.5 μΩ⋅cm was obtained, which is comparable to that of the AlNd metal alloy for the gate electrode of TFT‐LCD. Furthermore, we evaluated the transfer characteristics of an a‐Si:H TFT using directly printed silver material as a gate line.