Polarization dependent refractive index of an interdiffusion induced AlGaAs/GaAs quantum well

Abstract

The polarization dependent refractive index, nR, at room temperature is calculated for interdiffusion-induced Al0.3Ga0.7As/GaAs single quantum well (QW) structures for the wavelength range 0.75–2 μm. The confinement profile is modeled by an error function and nR is determined using the real and imaginary parts of the dielectric function, including contributions from the Γ, X, and L Brillouin zones. Results show that at longer wavelengths nR decreases with increasing interdiffusion, which normally provides a positive index step with respect to a less interdiffused QW. For shorter wavelengths (around the QW band edge), the wavelength range for a positive refractive index step increases as the extent of disordering between two interdiffused QWs is increasing.