Abstract

A gain medium for 1.3 μm amplifiers of fiber communication networks has to have (a) high and isotropic gain in (1.28-1.32) μm range, and (b) high pumping efficiency at wavelengths of most suitable pump sources (for instance, diode lasers). The utilization of ⁴F_3/2-⁴I_13/2 transition of Nd³⁺ ions in crystals and glasses is one of the ways to solve this problem. But two main difficulties have to be overcome for Nd doped media. First of all, it is necessary to shift Nd³⁺ emission to the desired spectral position, since the fluorescence of Nd³⁺ ions is usually observed at wavelengths around 1.34 μm. The second obstacle is excited state absorption (ESA) at ⁴F_3/2-⁴G_7/2 transition, that can reduce or suppress totally gain at ⁴F_3/2-⁴I_l3/2 transition.

© 1995 Optical Society of America