Tunable coherent light source emitting at the visible region has long been recognized as a key asset, especially with a monolithic design involved, for the increasing number of emerging applications in the scientific research and industrial manufacturing. Here, an efficient 640 nm solid-state laser is used as a pump source, and the fiber end-facet mirrors construct a fiber laser resonator. We experimentally developed green wavelength-tunable Ho3+-doped all-fiber upconversion lasers, which corresponds to the transitions originating from the Stark levels within thermally-coupled 5 S2, 5 F4 states and terminating on the 5 I8 ground state. Moreover, a high power 236 mW and a high efficiency 38.9% of green upconversion fiber laser operating at 544 nm was demonstrated, and the output power achieved is six-times higher than before. Such compact tunable and high power green fiber lasers are very attractive for the practical applications in optical communications, spectroscopy, sensing, and optical switching devices.

中文翻译：

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绿光波长可调谐高功率 Ho3+ 掺杂上转换光纤激光器


在可见光区域发射的可调谐相干光源长期以来一直被认为是科学研究和工业制造中越来越多的新兴应用的一项关键资产，特别是涉及单片设计。这里，采用高效的640 nm固态激光器作为泵浦源，光纤端面镜构成光纤激光谐振腔。我们通过实验开发了绿光波长可调谐Ho3+掺杂全光纤上转换激光器，其对应于源自热耦合5 S2、5 F4态内的斯塔克能级并终止于5 I8基态的跃迁。此外，还展示了工作在544 nm的高功率236 mW、高效率38.9%的绿光上转换光纤激光器，输出功率比以前提高了六倍。这种紧凑的可调谐高功率绿光光纤激光器对于光通信、光谱学、传感和光开关器件的实际应用非常有吸引力。