Towards High-Power and -Efficiency ∼2.8 μm Lasing: Lightly-Erbium-Doped ZrF4 Fiber Laser Pumped at ∼1.7 μm

• DOI: 10.1109/jlt.2023.3305608
• Publication Date: 2023-08-16T17:30:15Z
• Authors: Hongyu Luo; Junchuan Shi; Junsheng Chen; Yongzhi Wang; Jianfeng Li; Han Wu; Yong Liu

In this article, we demonstrate great potential of lightly-erbium(Er <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> )-doped ZrF <sub xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> fiber in efficient power scaling at ∼2.8 μm, when excited ∼1.7 μm. Core-pumped by a random Raman laser 1.69 the 1.5 mol.% Er -doped F-P cavity has experimentally yielded an output >6 W 2.783 μm with slope efficiency up to 58.4% (with respect absorbed pump), close its Stokes limit 60.7% (1.69/2.783). To our knowledge, is highest lasers mid-infrared. Further only limited current pump power. Based on validated numerical model, dominant role state absorption (ESA) process (i.e., <inline-formula xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^4{\mathrm{I}}_{13/2}{ \to }^4{\mathrm{I}}_{9/2}$</tex-math></inline-formula> ) exciting been highlighted, and resonant ground notation="LaTeX">$^4{\mathrm{I}}_{15/2}{ }^4{\mathrm{I}}_{13/2}$</tex-math></inline-formula> also essential. The simulation results indicate that wavelength closer ESA peak can yield higher efficiency. addition, heat load analyses via modeling reveals notation="LaTeX">$^4{\mathrm{I}}_{9/2}{ }^4{\mathrm{I}}_{11/2}$</tex-math></inline-formula> multiphonon relaxation main source system. By taking optical damage into account simultaneously, high-power lightly-Er arrangement proposed, which theoretically enables 100-W-class under >50% relatively low load.