Investigation of the impurity-induced layer disordering of GaInP (2 monolayers)/AlInP (2 monolayers) superlattice and multi-quantum-well (MQW) active layer in GaInP/AlInP quantum-well distributed Bragg reflector laser diode and its effect on the band gap was performed using transmission electron microscopy, photoluminescence and secondary ion mass spectrometry (SIMS). The GaInP/AlInP superlattice and MQW active layers were completely disordered by Zn diffusion even at 650-degrees-C for 5 min. The band gap of active layer was increased by DELTAE=155 meV after Zn diffusion. Segregation of Zn was also observed by SIMS analysis.