Diode-cladding-pumped Yb3+, Ho3+-doped silica fiber laser operating at 2.1-μm

The characteristics of the performance of a diode-cladding-pumped Yb3+, Ho3+-doped silica fiber laser are presented. To our knowledge this is the first demonstration of a Yb3+, Ho3+-doped fiber laser, and a maximum output power of 0.85 W was achieved for a launched pump power of 10.9 W. For launched pump powers <7 W, the slope efficiency was similar to12.5%. Visible fluorescence emission with peaks at similar to485, similar to550, and similar to660 nm measured at the output from the laser suggests that excited-state absorption and energy-transfer upconversion losses may impair the functioning of the laser. Increasing the Yb3+ and Ho3+ concentrations and the Yb3+:Ho3+ concentration ratio may lead to an improvement in the overall efficiency of the device. (C) 2003 Optical Society of America.