The value of the a (Alpha) parameter, which is also called Linewidth enhancement factor, is particularly important in optical communication systems. This paper presents a new approach based on artificial neural networks (ANNs) to determine the a parameter for different number of quantum-wells (QWs). ANNs are trained in different structures with the use of five learning algorithms to obtain better performance and faster error convergence. The Levenberg-Marquardt (LM) algorithm, which has a quadratic speed of convergence, gives the best result among other learning algorithms used in the analysis. Both the training and the test results are in very good agreement with the experimental results reported elsewhere. (C) 2004 Elsevier Ltd. All rights reserved.