Effects of dispersion and birefringence on the performance of quantum well mode converters

The device characteristics of GaAs multiple quantum well (MQW) polarization modulators, designed for operation at wavelengths of 865 and 870 nm, respectively, are investigated and shown to depend strongly on the dispersive and anisotropic optical properties of the quantum well medium. Results indicate that the observed decrease in spectral bandwidth and conversion efficiency at wavelengths detuned from the excitonic bandgap by approximately 250 AA can be accounted for, theoretically, if electroabsorptive loss terms are included in the coupled-mode analysis of polarization conversion in MQW waveguides. Device design considerations and applications of MQW polarization modulators to integrated optic filtering, wavelength division multiplexing/demultiplexing, and the frequency tuning of semiconductor lasers are presented. >