We examine the effective linear and the third-order nonlinear optical susceptibilities of an InAs/GaAs semiconductor quantum dot with a cascade exciton-biexciton configuration that is strongly driven by a nearly resonant pump electromagnetic field, while, at the same time, it interacts with a weak electromagnetic field. We assume that the applied fields are linearly polarized, which permits us to simplify the relative energy level diagram by using a three-level ladder-type scheme. We derive the equations of motion, in the dipole approximation, in a rotating frame, and follow an expansion approach to calculate the components of the density matrix which are associated to the effective linear and the self-Kerr third-order nonlinear optical susceptibilities. We present the spectra of the first-order susceptibility and the self-Kerr susceptibility and investigate the dependence of their profiles on the Rabi frequency and the detuning of the pump field, in the one-photon and the two-photon resonance regimes. The role of the biexciton energy shift on the susceptibilities is also studied. In addition, we present a dressed state analysis which appears to be crucial for obtaining a better understanding of several spectral properties of the susceptibilities.
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