Numerical analysis of polarization sensitivity in strained bulk semiconductor optical amplifiers

Polarization dependence in 1.55-μm SOAs based on tensile-strained bulk InGaAsP is analyzed numerically, focusing on strain relaxation in the active layer. We demonstrate that the strain introduced during the epitaxial growth of the active layer is reduced due to the InP-buried structure. The polarization dependence of the gain is calculated by using the k·p method taking strain relaxation into account and compared with experimental results. The change of strain has non-negligible effects that have to be considered in choosing of the strain for polarization independence of the gain