Modeling of excitonic electrorefraction in InGaAsP multiple quantum wells

The absorption spectra in an InGaAsP/InP multiple quantum well for different values of electric field, applied perpendicularly to the quantum well layer planes, are delineated by modifying the model given by P.J. Stevens et al. (IEEE J. Quantum Electron., vol.24, pp.2007-2015, 1988). The essential deviations in the present model lie in the inclusion of the additional broadening of excitons due to composition fluctuation in the quaternary, the forbidden transition between the second heavy hole subband and the first conduction subband, an improved excitonic envelope function dependent on both the in-plane and transverse separation of electrons and holes, and a modified calculation of oscillator strength. The modeled curve's are then used to calculate the values of Delta n, the change in refractive index due to field, and the ratio Delta n/ Delta k, where Delta k is the extinction coefficient, using Kramers-Kronig relations. The calculated values are found to agree with the experimental data for 1.537 mu m.>