Quasi-phase-matched optical parametric oscillator using periodically poled MgO-doped LiNbO3 crystal

A 0.5-mm-thick periodically poled MgO-doped (5 mol%) LiNbO3 (PPMgLN) crystal with domain-inverted periods of 26.2-32.0 mu m 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 degrees C were comparable to those of a PPLN crystal heated to similar to 100 degrees C to prevent photorefractive damage, which enables operation in the steady state at room temperature.