SATURATION OF THE 2.71-MU-M LASER OUTPUT IN ERBIUM-DOPED ZBLAN FIBERS

The saturation of the 2.71 mu m laser output power has been investigat ed in an erbium doped ZBLAN single-mode fiber with an Er3+ concentrati on of 5000 ppm mol. The bleaching of the ground state, the absorption coefficient at the pump wavelength and the fluorescence intensities ov er a wide wavelength range have been measured simultaneously during la ser emission. In a computer simulation the rate equation system of the Er3+ system in ZBLAN fibers has been analyzed. The saturation of the 2.71 mu m laser output is explained by simultaneous lasing at 850 nm.