High-power very large mode-area thulium-doped fiber laser.

  title={High-power very large mode-area thulium-doped fiber laser.},
  author={Florian Jansen and Fabian Stutzki and C{\'e}sar J{\'a}uregui and Jens Limpert and Andreas T{\"u}nnermann},
  journal={Optics letters},
  volume={37 21},
Large-pitch photonic-crystal fibers have demonstrated their unique capability of combining very large mode areas, high output powers and robust single-mode operation at a wavelength of 1 μm. In this Letter, we present the experimental realization of thulium-doped very large mode-area fibers based on the large-pitch fibers with record mode-field diameters exceeding 60 μm and delivering more than 52 W of output power.