MgO:LiNbO $_{3}$ Waveguide Quasi-Phase-Matched Second-Harmonic Generation Devices Fabricated by Two-Step Voltage Application Under UV Light

A new simple method for formation of MgO:LiNbO 3 domain inverted gratings is demonstrated. Periodic domain structure was formed on - z face by first voltage application under ultraviolet (UV) light with periodic intensity distribution. Following second voltage application without UV resulted in periodic structure continuing through crystal thickness. A waveguide quasi-phase-matched (QPM) nonlinear-optic device was fabricated by the method and characterized. The device performance agreed with approximate theoretical prediction, and high applicability of the method to QPM device fabrication was demonstrated.