Diode-Cladding-Pumped Yb 3 +, Ho 3 +-Doped Silica Fiber Laser Operating at 2.1(mu)m

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 ~12.5%. Visible fluorescence emission with peaks at ~485, ~550, and ~660 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.