Efficient, single-axial-mode operation of a monolithic MgO:LiNbO3 optical parametric oscillator

A monolithic doubly resonant optical parametric oscillator (OPO) fabricated from MgO:LiNbO3 was pumped by a cw, frequency-doubled, diode-laser-pumped Nd:YAG laser. The threshold for cw operation was 12 mW, and pump depletions of up to 78 % were observed two times above threshold. The total OPO output power was 8.15 mW, with a conversion efficiency for the incident pump of 34 % and combined conversion efficiency for the 1064-nm laser light of 14%. The OPO was temperature tuned from 1007 to 1129 nm, operated on a single-axial-mode pair over most of the range, and could be electric field tuned by as much as 38 nm near degeneracy. Optical parametric oscillators ' (OPO's) are currently enjoying a revival of interest. New materials and im-proved pump sources are enabling OPO's to live up to their decades-old promise of providing efficient, nar-row-band, widely tunable sources of light. In the cw long-pulse regime OPO's have been demonstrated in lithium niobate (LiNbO3) as narrow-linewidth sources using the singly resonant configuration2 and in LiNbO 3 waveguide devices with low thresholds. 3