Long-term, mode-hop-free operation of a continuous-wave, doubly resonant, monolithic optical parametric oscillator

More than 24-h mode-hop-free operation of a continuous-wave doubly resonant monolithic optical parametric oscillator (OPO) was demonstrated using 5% MgO-doped LiNbO3 as a nonlinear crystal. The OPO was pumped by a 532-nm Nd:YAG laser with 68 mW power, and generated 4 mW of signal power at 807 nm and 3 mW of the idler power at 1561 nm. The OPO maintained a single longitudinal signal and idler mode pair even under the free running condition, owing to the high mechanical stability of the monolithic structure and the strong thermal self-locking mechanism. By stabilizing the crystal temperature so as to maintain the output power constant, the drift of the output power could be suppressed completely and a power fluctuation of 1.3% rms was achieved. (C) 2000 Elsevier Science B.V. All rights reserved.