MODELING OF EXCITONIC ELECTROREFRACTION IN INGAASP MULTIPLE-QUANTUM WELLS

We have delineated the absorption spectra in an InGaAsP/InP multiple q uantum well for different values of electric field, applied perpendicu lar to the quantum well layer planes, by modifying the model given by Stevens et al. (IEEE J. Quantum Electron., vol. 24, pp. 2007-2015, 198 8.) The essential deviations in our present model lie in the inclusion of the additional broadening of excitons due to composition fluctuati on in the quaternary, the forbidden transition between the second heav y hole subband and the first conduction subband, an improved excitonic envelope function dependent on bath the in-plane and transverse separ ation of electrons and holes and a modified calculation of oscillator strength. The modeled curves are then used to calculate the values of Delta n, the change in refractive index due to field, and the ratio De lta n/Delta k, where Delta k is the extinction coefficient, using Kram ers-Kronig relations. The calculated values are found to agree with th e experimental data for 1.537 mu m.