Er(3)/Yb(3)-codoped phosphate glass for short-length high-gain fiber lasers and amplifiers.

Er3+/Yb3+-codoped phosphate glass with compositions of (78.2 - x)P2O5-14Al(2)O(3)-5Li(2)O-1K(2)O-1.8Yb(2)O(3)-xEr(2)O(3) (x = 0.2, 0.4, 0.6) in mol. % were investigated. Judd-Ofelt (JO) intensity parameters have been calculated to predict radiative properties based on absorption spectra. The stimulated emission cross section (sigma(e)) calculated according to McCumber theory was 1.50 x 10(-20) cm(2), almost twice larger than values reported before. The effective line width (Delta(eff)), full width at half-maximum (FWHM) and the quality parameters for designing optical amplifier devices were listed in the table compared with other types of phosphate glass matrices. A theoretical model of a Er3+/Yb3+-codoped system based on rate and power propagation equations was put forward to investigate the potential advantages of the materials applied for short-length, high-gain fiber amplifiers. A simulated gain of 32.2 and 2.6 dB/cm per unit length was achieved in 12.5-cm-long fiber. (C) 2015 Optical Society of America