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 Al0.3Ga 0.7As/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.