Crystal fiber of cubic Yb3+ -doped KY3F10 has been grown. Both, mono-doped and concentration gradient fibers were grown by laser-heated pedestal growth (LHPG) method under argon atmosphere. The preparation of feed rod materials under CF4 atmosphere prior to LHPG is efficient to obtain oxygen-free fluorides. Yb3+ -doped KY3F10 crystals have excellent spectroscopic properties, weak self-quenching property and can be expected for solid-state laser application. (C) 2007 Elsevier B.V. All rights reserved.