M. Nakamura et al., Quasi-phase-matched optical parametric oscillator using periodically poledMgO-doped LiNbO3 crystal, JPN J A P 2, 38(11A), 1999, pp. L1234-L1236
A 0.5-mm-thick periodically poled MgO-doped (5 mol%) LiNbO3 (PPMgLN) crysta
l 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 proce
ss. The average ratios of the domain-inverted width to the domain-inverted
period (duty cycle) were approximately 50%. Experiments on quasi-phase-matc
hed (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) crys
tal. OPO properties of the PPMgLN crystal at 20 degrees C were comparable t
o those of a PPLN crystal heated to similar to 100 degrees C to prevent pho
torefractive damage, which enables operation in the steady state at room te
mperature.