Yb³⁺-doped large-mode-area photonic crystal fiber for fiber lasers prepared by laser sintering technology

In this paper it is demonstrated that laser sintering technology combined with fiber fabrication by the stack and draw method can be used to realize efficient fiber lasers. More precisely, a ytterbium-doped large-mode-area photonic crystal fiber with a core obtained by laser sintering technology is studied. Electron probe micro-analysis (EPMA) mapping reveals that the elements Yb, Al and Si are distributed throughout the fiber core with an excellent homogeneity. The laser performance demonstrates a high laser slope efficiency of 81.03 % for a laser emission at 1035 nm and a low power threshold of 3.04 W within only 1 m of fiber. The optical and spectroscopic properties of the fiber are studied, together with the sensitivity of the fiber to photodarkening (PD). The results make laser sintering technology interesting for the realization of fibers with large core and complex designs toward high-power fiber lasers.