Recently, we have been developing an inductively coupled argon plasma-enhanced QWI technology for tuning the bandgap of InGaAs/InP QW laser structure. The application of ICP energy plays a strong role to the interdiffusion of point defects instead of the ion bombardment mechanism, resulting in high degree of intermixing. The effects of the plasma-induced defects, the factors that affect the QWI process and the general correlations of the plasma exposure effect to bandgap shift have been well understood with the analytical model. The theoretical results appear to be in good agreement with the experimental data of the intermixed samples. The model serves as a good simulation tool to explain the intermixing mechanism and further to optimize the intermixing process for the fabrication of the photonic integrated circuits. (C) 2004 Elsevier B.V. All rights reserved.