Unidirectional dual-wavelength pumping at 805 and 975 nm of a Tm 3+ -doped silica double-clad fiber laser that has been codoped with Yb3+ is demonstrated. With equal 2-wt. % concentrations of the Tm3+ and Yb3+ ions, slope efficiencies of 49% (57%) and 35% (40%) with respect to the launched (absorbed) pump power of the 805- and 975-nm pump wavelengths, respectively, were obtained. Efficient Yb3+ → Tm3+ energy transfer and efficient cross relaxation combined with minimal upconversion losses were thus operating. At the maximum output power of 18 W, the fiber laser operated at a center wavelength of 2050 nm.
|Number of pages||3|
|Publication status||Published - 15 Nov 2003|