An electroluminescent diode with a periodic multilayer structure consisting of alternating layers of 8-hydroxyquinoline aluminum and aromatic diamine has been fabricated by organic molecular beam deposition. The polarization anisotropy of the emission spectrum and intensity of the light propagating in the organic layers of the diode have been observed. The mechanism of the emission anisotropy in the periodic multilayer structure has been discussed in terms of optical interference in the emission layers.