Spectral dependences of transmittance (T) and wavelength modulated transmittance (ΔT/Δλ) of As₂S₃ layers doped by manganese (Mn) of different concentrations (0–0.5%) were investigated at temperatures from 10 to 300 K. Photoluminescence bands at 1.762, 2.107 and 2.282 eV due to transition (Formula Presented) of Mn ions, respectively were observed at argon laser excitation. On the luminescence spectra the absorption bands of electron transitions (Formula Presented) were recognized. The magnitude of refractive index (n) of Mn (0.1 and 0.5%) ions doped As₂S₃ layers in low-energy range (1.6–1.9 eV) does not change at temperature decreasing from 300 to 10 K. The spectral dependences of refractive indices of As₂S₃ samples doped with Mn ions of different concentrations (0.1 and 0.5%) did not have any features.