Flat gain cross-section of 1.5 μm amplifier in Er3+-doped oxyfluoride glass-ceramics

Room temperature emission and absorption spectra corresponding respectively to the I-4(3/2) <----> I-4(15/2) transitions of the Er3+ in oxyfluoride glass-ceramics, 32(SiO2) 9(AlO1.5) 31.5(CdF2) 18.5(PbF2) 5.5(ZnF2): 3.5(ErF3) mol%, and its parent precursor glass, have been measured. The concentration of Er3+ ions has been estimated at 1.06 x 10(21) ions/cm(3) from a molar density measurement. The radiative lifetime tau(rad) of the emitting level I-4(13/2) was obtained from the experimental absorption oscillator strength. The stimulated emission cross-section has been calculated based on the experimental spontaneous emission spectrum using the Fuchtbauer-Ladenburg equation. Using the measured absorption and calculated stimulated emission cross-sections, the wavelength dependence of the net gain cross-section, as a function of population inversion of the excited I-4(13/2), and ground I-4(15/2) states, has been computed. In the glass-ceramic sample, gain was found to be almost flat in the range 1.50 to 1.56 mum, corresponding to S- and C-bands of telecommunications, for population inversion between 0.8 to 1.0. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.