The visible photoluminescence of Tb3+-doped germanate glass of composition (in mol%) 40GeO2-20Na2O-40SiO2 has been investigated for two Tb3+ concentrations. By using steady-state and pulsed laser spectroscopy. Concentration effects on luminescence are observed for Tb3+ concentration higher than 0.9 mol%. The thermo-optical characteristics were measured at room temperature under resonant conditions on the Tb3 ions. The thermo-optical properties of the glasses showed a dependence on the concentration of terbium ions. The effects of TL were also analyzed in terms of a theoretical model for CW laser induced thermal lensing under a Gaussian-beam approximation. Tb3+ concentration quenching effects on the dependence of thermo-optical properties are discussed. © 2007 Elsevier B.V. All rights reserved.