报道了基于掺MgO周期极化铌酸锂(MgO: PPLN)晶体的可调谐连续光参量振荡器。该光参量振荡激光器采用了多周期可调谐的MgO: PPLN作为非线性光学晶体, Nd: YVO4为激光晶体的紧凑型半导体激光端面抽运直线腔系统。实验中采用的MgO: PPLN晶体包含28.5~31.5 μm之间的7个极化周期, 相邻极化周期的间隔为0.5 μm。通过调节7个极化周期实现信号光波长1.43~1.67 μm和闲频光波长2.93~4.16 μm的激光调谐输出。对同一温度下不同极化周期对应的输出波长进行理论计算, 与实验结果符合较好。对比分析了输出功率随着不同极化周期和抽运功率的变化关系。当半导体激光入射抽运功率为15.4 W, 在31 μm极化周期和35 ℃的控制温度下, 最高获得了2.94 W的1 595 nm信号光和1.45 W的3 190 nm闲频光, 对应的光光转换效率达28.5 %。

A compact, intra-cavity widely tunable continuous-wave singly resonant optical parametric oscillator (SR-OPO) was reported based on a MgO-doped periodically poled lithium niobate (MgO: PPLN). A diode-pumped Nd: YVO4 laser at 1 064 nm was employed as the pump source of this SR-OPO with a compact linear cavity. The MgO: PPLN crystal used contained seven different periodically poled gratings from 28.5 to 31.5 μm with a step of 0.5 μm between the neighbor periods. The output wavelengthes at the different grating periods of MgO: PPLN crystal was measured, which was well matched with the theoretical value. The widely tunable SR-OPO output signal wavelength range from 1.43 to 1.67 μm and idler wavelength range from 2.93 to 4.16 μm were achieved. The output power as the function of grating periods and pump power was investigated. Under an incident pump power of 14.5 W, a maximum signal output power of 2.94 W at 1 595 mm and an idler output power of 1.45 W at 3 190 nm were obtained with the temperature controlled at 35 ℃ and the period set at 31 μm. The diode to OPO total output conversion efficiency reached 28.5%.