Methods of experimental investigations of the stress distributions in semiconductor laser crystals, which are based on the deformation-potential effect, are presented. The results of the development of the system and methods for measuring the spatially resolved emission spectra of laser-diode bars, which are incorporated in radiators produced by the All-Russian Research Institute of Technical Physics, are presented. The values of the packaging-induced stresses in laser-diode bars are quantitatively assessed for several variants of the materials in radiator structures, which differ in their physical and mechanical characteristics.