Quasi-Phase-Matched Optical Parametric Oscillator Using Periodically Poled MgO-Doped LiNbO 3 Crystal

A 0.5-mm-thick periodically poled MgO-doped (5 mol%) LiNbO3 (PPMgLN) crystal with domain-inverted periods of 26.2–32.0 µm and an interaction length of 30 mm has been successfully fabricated by an electric field poling process. The average ratios of the domain-inverted width to the domain-inverted period (duty cycle) were approximately 50%. Experiments on quasi-phase-matched (QPM) optical parametric oscillation (OPO) using a PPMgLN crystal were performed. During QPM-OPO, the PPMgLN crystal exhibited a higher resistance to photorefractive damage than did a periodically poled LiNbO3 (PPLN) crystal. OPO properties of the PPMgLN crystal at 20°C were comparable to those of a PPLN crystal heated to ∼100°C to prevent photorefractive damage, which enables operation in the steady state at room temperature.