中红外连续波光学参变振荡技术是非线性变频领域关注的热点。它在激光通信、光谱学研究、遥感技术以及**上的红外对抗等方面具有重要的应用。分析和对比了用于中红外输出的非线性晶体的主要特性，简单综述了国内外中红外连续波光学参变振荡技术的实验与理论研究情况，并基于研究现状提出其未来一些的研究方向。目前，中红外连续波光学参变振荡器能够实现3～5 μm范围，输出功率范围在百毫瓦到十瓦之间的高稳定性、宽调谐的光输出。随着激光器技术的发展和周期性极化晶体性能的进一步提高，下一步有望在更大调谐范围内实现更高功率的中红外连续激光输出。

Mid-infrared continuous-wave optical parametric oscillator (CW-OPO) is the focus in the field of nonlinear frequency conversion. It has important applications in optical communication, spectroscopy, remote sensing and infrared countermeasure. We analyzed the main features of the nonlinear crystal which is used to produce mid-infrared laser, and overviewed the experimental and theoretical researches of mid-infrared CW-OPO. We also proposed some of its future research directions. Currently, mid-infrared CW-OPO can achieve the output power from a hundred millwatts to ten watts in 3～ 5 μm with high stability, wide tunability. With the development of laser technology and periodically poled crystals with further improved performance, the next step is expected to achieve higher-power mid-infrared continuous-wave laser output in a larger tuning range.