Contribution of the bandhyphen;filling effect to the effective refractivehyphen;index change in doublehyphen;heterostructure GaAs/AlGaAs phase modulators

摘要

In this work we have theoretically estimated the effective refractivehyphen;index variation Dgr;neffdue to the removal of carriers in the depletion region of a doublehyphen;heterostructure (DH)nhyphen;AlGaAs/nhyphen;GaAs/phyphen;AlGaAs phase modulator when a reverse bias is applied to this structure. Dgr;neffis calculated by a Kramersndash;Kronig analysis of the absorption spectrum, which changes around the absorption edge because of the bandhyphen;filling effect associated with the presence of carriers. We also calculated the phase shift Dgr;fgr; due to Dgr;neff, and we showed that this contribution due to the bandhyphen;filling effect can account for up to 28percnt; of the total phase shift for a specific DH structure, showing in this way that the bandhyphen;filling effect can no longer be ignored in the analysis of phase modulators.