Abstract: The characteristics of the green ($lambda approximately 550 nm) holmium upconversion fiber laser have been studied in detail in Ho:ZBLAN fibers ranging in length from approximately 20 to 86 cm. When pumped in the red (approximately 643 nm), slope efficiencies up to 24% are observed for a 21 cm long fiber and a cavity output coupling of 30%. More than 38 mW of output power is observed for 280 mW of absorbed pump power. The influence of the depletion of the ground state ($+5$/I$-8$/) population on the emission spectrum and overall efficiency of the oscillator are discussed. !3
展开▼
