LD泵浦瓦级单模高掺铒中红外光纤激光器(英文)

Laser Diode-pumped Watt-level Single Mode Heavily Erbium-doped Mid-infrared Fiber Laser

中红外激光在激光医疗、激光光谱学和红外对抗等领域有着广泛的应用前景.为了获得结构紧凑、便携性好的中红外激光源,采用975nm半导体激光器泵浦高掺铒氟化物双包层光纤实现了2.8μm的中红外光纤激光输出.将光纤耦合输出的中心波长为975nm的半导体激光,经过消像差非球面透镜系统耦合进双包层光纤,激光谐振腔由高反镜和具有4%菲涅耳反射率的光纤端面组成,当注入到增益光纤的泵浦功率高于0.37 W时,获得了中红外激光输出.实验结果表明:中红外光纤激光器中心波长为2.785μm,谱宽0.9nm;工作阈值为0.37W,最大输出功率为0.98W,斜率效率为17%,激光工作模式为单模.利用高掺杂浓度铒离子间的能量转移上转换,获得了高效率瓦级单模中红外光纤激光输出.

Mid-infrared lasers have a lot of potential applications, such as laser medicine, spectroscopy and infrared countermeasures. In order to obtain a compact and potable mid-infrared laser source, a diode-pumped fiber laser emitting at 2.8 μm from a heavily erbium-doped ZrF4-BaF2-LaF3-AlF3-NaF double-clad fiber was demonstrated. A fiber-coupled laser diode centered at 975 nm was coupled into the inner cladding as the pumping source by an achromatic coupling system consisted of two aspheric lenses. The laser cavity was composed of a protected gold mirror butted against the rear end of the active fiber, and the other end with 4% Fresnel reflection. The 2.8 μm lasing was achieved when the launched pump power was higher than 0.37 W. The experimental results indicated that the center wavelength and linewidth of free running were 2.785 μm and 0.9 nm, respectively. Moreover, the maximum output power of the fiber laser working at the transverse-fundamental-mode was 0.98W, corresponding to the slop efficiency of 17%. High efficient watt-level single mode mid-infrared fiber laser was obtained using the efficient energy transfer upconversion processes between Er-Er ions.