高性能可调谐可见光光纤激光器是当前激光技术领域的前沿课题和研究热点，具有重要科学意义和实用价值。高功率光纤激光MOPA结合SHG/SFG-OPO是实现高功率宽调谐单频可见光输出的最佳技术方案。针对其可见光输出功率普遍较低的问题，本申请提出级联非线性过程转换效率平衡优化的解决方法。理论上建立SHG/SFG过程和参量下转换过程相联立的耦合波方程模型，分析二者间相互影响制约的作用机制，综合考虑泵浦、晶体参数、腔型结构、腔内功率密度等因素对转换效率的影响，得到具有普遍意义的SHG/SFG-OPO优化条件。实验上搭建高功率1064nm单频光纤MOPA并高效倍频产生532nm单频绿光，以此为基础实现基于SHG/SFG-OPO的高性能可见光单频光纤激光器，根据理论模型对级联非线性过程转换效率进行主动调控以实现同时优化，获得覆盖红、绿、蓝等主要波段的高功率、宽调谐单频可见光输出。

High-performance fiber-based lasers tuning in the visible, which are of great scientific significance and application value, have been frontier and hotspot of current laser research. High power fiber MOPA combined with SHG/SFG-OPO is the most reliable technic to achieve this purpose. However, for most such kind systems, high pumping power have not been fully extracted and thus visible output are limited. For this reason, the idea of balanced optimizing of the two cascaded nonlinear processes are proposed herein. The theoretical model which simultaneous the couple-wave equations of both processes of intracavity SHG/SFG and parametric down conversion will be built to analyze their interaction mechanism on each other. Considering the influence of pumping, nonlinear crystal parameters, cavity structure and intracavity power intensity, the optimum condition for enhanced visible output of high power SHG/SFG-OPO can be obtained. In the experiment, high power single-frequency fiber MOPA at 1064nm and subsequent frequency-double green laser at 532nm will be build and thus high-performance SHG/SFG-OPO in visible could be realized based on them. After optimizing the efficiency of the cascaded nonlinear processes simultaneously according to the theoretical model, high-power single-frequency visible output widely tuned across important red, green and blue can be obtained.