Abstract
We propose a novel method for controlling the shape of a short period domain-inverted structure utilizing a multi-pulse poling method. Using this technique, periodically domain-inverted structures with periods of 1.4-2.4 μm were fabricated for over 10 mm interaction length in 2 mm thick Z-cut MgO: LiNbO3 crystal. We have demonstrated highly efficient ultraviolet light generation (340-390 nm) using bulk QPM-SHG devices with these structures. Continuous wave 72 mW at wavelength of 372 nm was generated with conversion efficiency of 17 %.