Single-mode operation using 15 and 25 µm core double-clad Tm-doped fiber with >50% efficiency for 2 μm applications

As 2 µm fiber laser technologies mature, an increased number of applications are seeking industrial-grade fiber lasers and amplifiers able to deliver hundreds of Watts of 2 µm laser light at reasonable cost. To meet these criteria, novel Tm-doped double-clad fibers are proposed, able to achieve the target power level in a high-volume manufacturing setup. The new TDFs are designed to achieve good beam quality (M2 < 1.1) and high efficiency (> 50%) without the need of a pedestal layer around the core, which often compromises smooth implementation in high-volume production. Two versions of these fibers are proposed with 15 and 25 µm core diameters to enable customers to design competitive systems using either single-oscillator or amplifier designs.