A numerical investigation on the nonlinear optical rectification, second and third harmonic generation coefficients in asymmetric double n-type δ-doped GaAs quantum well is performed in order to identify the influence of non-resonant intense laser radiation, doping concentration and the change in well widths. The energy eigenvalues and the corresponding eigenfunctions are determined by using effective-mass and parabolic band approximations. The working analytical expressions for the optical coefficients are derived from the iterative solving of compact-density matrix description of dielectric susceptibility. The obtained results reveal that the position and amplitude of the nonlinear optical rectification, second and third harmonic generation coefficients can be altered by modifying the external field as well as the compositional and geometrical setups. © 2020, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.