Electrorefraction in strained InGaAs/InP chopped quantum wells: Significance of the interface layers

We present a model for electrorefraction based on the quantum confined Star k effect (QCSE) in strained InGaAs/InP chopped quantum wells (CQWs) consist ing of three 27 Angstrom InGaAs wells separated by 15 Angstrom InP barriers . The model fully takes into account the influence of the thin interface la yers around each well. We experimentally verify the model on a InGaAs/InP C QW which combines a large 60 meV QCSE redshift at 11.7 V bias with waveguid e transparency at 1.55 mu m, which is two times larger than in a InGaAsP qu aternary well. The calculated electroabsorption spectra of the CQWs are in good agreement with experiment. We finally applied the Kramers-Kronig trans formations for calculating the switching voltage in a Mach-Zehnder switch e mploying CQWs in the phase shifting section. The model was found to be in g ood agreement with experiment for both polarizations. (C) 2000 American Ins titute of Physics. [S0021-8979(00)08005-1].