Contribution of single InGaAs quantum wells to the guided mode dispersion of InGaAs/GaAs/AlGaAs waveguides: Model and experimental results

Abstract

High resolution Fabry–Perot fringe spacing measurements are used to determine the group index dispersion of TE and TM polarized modes in single quantum well InGaAs/AlGaAs/GaAs graded index separate confinement heterostructure waveguides. The TE mode data, over a ∼175 nm range below the quantum well band gap, is compared with model calculations of guided mode dispersion using existing empirical formulas for the index dispersion of AlxGa1−xAs and GaAs, and different phenomenological expressions for the TE index dispersion of the InGaAs quantum well. A satisfactory fit is obtained when the quantum well is modeled as a two-dimensional set of equal strength oscillators with a constant density of states, plus a single 1S excitonic level.