Polarization insensitivity in interdiffused, strained InGaAs/InP quantum wells

Theoretical results are presented showing how quantum well disordering affects the TE and TM absorption coefficient spectra of In_0.53Ga_0.47As/InP single quantum wells. An error function distribution is used to model the constituent atom composition after interdiffusion. Different interdiffusion rates on the group V and group III sublattices are considered resulting in a strained structure. With a suitable interdiffusion process the heavy hole and light hole ground state, excitonic transition energies merge and the absorption coefficient spectra near the fundamental absorption edge become polarization insensitive. The results also show that this polarization insensitivity can persist with the application of an electric field, which is of considerable interest in waveguide modulators.