THULIUM-ZBLAN BLUE FIBER LASER-PUMPED BY 2 WAVELENGTHS

We demonstrate and analyze an upconversion blue fiber laser pumped by two wavelengths. Lasing at 0.48 mu m with very low pump threshold powe r is obtained from a Tm-doped fluorozirconate fiber that is counterpro pagating pumped by 1.21- and 0.649-mu m light. We employed a rate-equa tion analysis using parameters obtained by fitting to the experimental data to predict the 0.48-mu m output characteristics as a function of fiber length and output reflectivity. (C) 1997 Optical Society of Ame rica.