Polarization-dependent refractive-index change induced by superlattice disordering

A model of the polarization-dependent refractive-index change that accompanies superlattice disordering is proposed for the first time. Calculated results agree well with experimental results in terms of the amount and direction of the refractive-index changes. In the GaAs-AlAs system, a simple diffusion model that considers the diffusion of group III atoms explains the experimental results. In a InGaAs-InP system, it is assumed that group V atoms mainly induce disordering, and the difference between the diffusion constant in wells and that in barriers is taken into account. The refractive-index changes induced by superlattice disordering are useful for fabricating polarization control devices and integrated optical circuits.