POLARIZATION-INDEPENDENT DELTA-STRAINED SEMICONDUCTOR OPTICAL AMPLIFIERS - A TIGHT-BINDING STUDY

We present a tight-binding analysis of the polarization dependence of GaAs delta-strained semiconductors optical amplifiers. Our approach al lows us to account for band nonparabolicity, valence band mixing, as w ell as thin layer perturbations, overcoming the natural limitations of standard techniques based on the envelope function formalism. We expl ain how thin strained GaAs layers embedded in a lattice-matched InGaAs P-InGaAs quantum well can be used to achieve polarization-insensitive optical amplification. The theory is also applied to other structures providing optical amplification, showing how the concept of ''virtual barriers'' can lead to high polarization insensitivity.