In this work, we studied the effects of in-plane magnetic field and Rashba spin-orbit interaction on the intersubband optical absorption coefficients and changes in refractive index for transitions between the first two lower-lying electronic levels of quantum wire represented by a parabolic confining potential. The analytical expressions of the linear and third-order nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact-density matrix formalism and iterative scheme. Optical properties are investigated as a function of quantum wire radius, strength and orientation of magnetic field, strength of Rashba spin-orbit interaction and photon energies. Numerical results reveal that the optical absorption coefficients and refractive index changes are strongly affected and thus can be controlled by these parameters. (C) 2015 Elsevier Ltd. All rights reserved.