A 20.6-W mid-infrared supercontinuum (MIR-SC) generation is demonstrated in a piece of step-index ZBLAN (ZrF4−BaF2−LaF3−AlF3−NaF) fiber. A silica-fiber-based SC laser operating at 1.9–2.6 μm is used as a pump source. Owing to the specially designed ZBLAN fiber which perfectly matches the pigtail of the pump source in mode-field-diameter, direct fusion splicing was achieved between the ZBLAN fiber and the pigtail of the pump source instead of being connected via a piece of transition fiber. The coupling loss of the fusion splicing joint between the silica fiber and the ZBLAN fiber was measured as 0.26 dB@2000 nm. Robust fiber endcap made of multimode AlF3 fiber also benefited high-power MIR-SC generation. Spectral and power characteristics of the generated SC under different pump pulse duration and pulse repetition rate were carefully studied. A 20.6-W SC was obtained with an overall spectral coverage and a 10-dB long wavelength edge of 1.92–4.29 μm and 4.08 μm, respectively. This is, to the best of the authors’ knowledge, the first demonstration of 20-W level SC laser based on ZBLAN fiber with long wavelength edge extending beyond 4 μm.

中文翻译：

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ZBLAN 光纤中产生 20.6 W 中红外超连续谱，光谱范围为 1.9-4.3 μm

一段阶跃折射率 ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) 光纤产生了 20.6-W 中红外超连续谱 (MIR-SC)。工作在 1.9–2.6 μm 的基于二氧化硅光纤的 SC 激光器用作泵浦源。由于特殊设计的ZBLAN光纤在模场直径上与泵浦源尾纤完美匹配，ZBLAN光纤和泵浦源尾纤实现了直接熔接，而不是通过一条过渡光纤连接。石英光纤和 ZBLAN 光纤熔接接头的耦合损耗测量为 0.26 dB@2000 nm。由多模 AlF3 光纤制成的坚固光纤端盖也有利于高功率 MIR-SC 的产生。仔细研究了不同泵浦脉冲持续时间和脉冲重复率下产生的 SC 的光谱和功率特性。一个 20。获得 6-W SC 的总光谱覆盖范围和 10-dB 长波长边缘分别为 1.92–4.29 μm 和 4.08 μm。据作者所知，这是基于 ZBLAN 光纤的 20 W 级 SC 激光器的首次演示，长波长边缘延伸超过 4 μm。