In the present work, the effects of electric and magnetic fields on the optical absorption coefficient and refractive index changes associated with intersubband transitions in a GaAs/AlxGa1-xAs double inverse parabolic quantum well are theoretically calculated within the effective-mass approximation. The expressions for the linear and third-order nonlinear absorption coefficients and refractive index changes are those obtained by using the compact density-matrix approach and iterative method. The results are presented as functions of the incident photon energy for different values of the applied electric and magnetic fields. It is found that the optical absorption coefficient and refractive index changes are strongly affected by the applied electric and magnetic fields. (C) 2013 Elsevier Ltd. All rights reserved.