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

We present a model for electrorefraction based on the quantum confined Stark effect (QCSE) in strained InGaAs/InP chopped quantum wells (CQWs) consisting of three 27 Angstrom InGaAs wells separated by 15 Angstrom InP barriers. The model fully takes into account the influence of the thin interface layers around each well. We experimentally verify the model on a InGaAs/InP CQW which combines a large 60 meV QCSE redshift at 11.7 V bias with waveguide transparency at 1.55 mu m, which is two times larger than in a InGaAsP quaternary well. The calculated electroabsorption spectra of the CQWs are in good agreement with experiment. We finally applied the Kramers-Kronig transformations for calculating the switching voltage in a Mach-Zehnder switch employing CQWs in the phase shifting section. The model was found to be in good agreement with experiment for both polarizations. (C) 2000 American Institute of Physics. [S0021-8979(00)08005-1].