周期极化掺镁铌酸锂光参量振荡器的输出光谱特性

Spectral Properties of Parametric Oscillator Based on Periodically Poled MgO-Doped Lithium Niobate

实验研究了基于多周期的掺镁铌酸锂晶体光参量振荡器（OPO），分析了光学参量振荡器的输出光谱特性。实验中，采用激光二极管（LD）端面抽运的声光调QNd：YVO4激光器作为光参量振荡器的抽运源，谐振腔采用双凹腔结构。在调Q开关重复频率为10kHz，周期极化掺镁铌酸锂（PPMgLN）晶体的温度为25．4℃的条件下，实验测得光学参量振荡器的振荡阈值为110mW。当输入的抽运光的平均功率为325mw时，获得了平均功率为84mw的信号光输出，其光-光转换效率为25．8％。通过改变周期极化掺镁铌酸锂晶体的温度（25．4～120℃）和极化周期（28．5～30．5μm），实现了信号光在1449．6～1635nm范围内的可调谐输出。在室温25．4℃时，观测到了抽运光与信号光的和频光的光谱。实验结果表明，光参量振荡器输出光谱的半峰全宽（FWHM）小于0．5nm。

Temperature tuning and domain period tuning optical parametric oscillator based on periodically poled MgO doped lithium niobate （PPMgLN） in singly-resonant was studied experimentally. The output spectrum of optical parametric oscillator was discussed. A laser diode （LD） end-pumped aeousto-optieally Q switehed Nd： YVO4 laser was used as the pump source. The double-concave cavity structure was employed as PPMgLN-optical parametric oscillator （OPO） resonance cavity. Under Q-switch repetition rate of 10 kHz and temperature of 25.4 ℃, the threshold pump power of 110 mW is gained. The signal output power of 84 mW is obtained with a pump power of 325 mW and optical-optical conversion efficiency is 25.8%. It generates signal wave-lengths tunable in the range of 1449.6-1635 nm by temperature tuning and domain period tuning of PPMgLN. The spectrum from frequency mixing between the pump and signal is obtained at 25.4 ℃. The experimental results show that the fullwidth at half-maximum （FWHM） of output spectrum is less than 0.5 nm.