In this letter we present for the first time the observation of quantum-confined transitions of a short-period sawtooth doping superlattice in photocurrent and luminescence. The luminescence was investigated with different laser intensities. Due to the nature of the band modulation of sawtooth doping superlattices, the resonant energies for optical transitions are dependent on the intensity of the laser beam. We present a model, which incorporates both the Kronig-Penney energy dispersion and the self-consistent intensity-dependent internal field to explain the observed energy shift. Furthermore, the differences between photocurrent and luminescence measurements are discussed.