In the present work, a detailed investigation of the influence of external perturbations, in particular intense terahertz radiation, static electric and magnetic fields on the electron-related optical responses such as total optical absorption coefficients and relative refractive index changes for a quantum well with the square tangent potential is presented. The subband energy levels and their corresponding wave functions are obtained by solving the one-electron Hamiltonian of the system under the framework of the effective-mass and parabolic band approximations. Optical coefficients are reported for varying incident photon energies. The numerical results show that the optical response is shifted towards the blue with the increase in the magnitude of the applied external fields. These results can provide an input for use in optoelectronic device applications.