Temperature-Dependent High-Speed Modulation and Wavelength Conversion Using Quantum-Well Lasers

91 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.A comprehensive study of temperature-dependent effects that determine the high-speed modulation response and wavelength conversion in long-wavelength semiconductor lasers is presented. The steady-state measurement of gain is presented through four different approaches, including the direct (Hakki-Paoli) measurement of polarization-resolved spectra, correlation of gain and spontaneous emission, techniques for measuring the transparency energy, and a hybrid technique combining the above approaches. Further steady-state measurements of linear gain, refractive index, and linewidth enhancement factor due to optical and electrical pumping are shown for Fabry-Perot lasers and semiconductor optical amplifiers. Gain spectra with and without an optical pump are measured; theoretical fits to the data and predicted carrier densities are obtained using a many-body gain model. The modulation response due to optical pumping at 1.3 mum wavelength is compared with the electrical response in order to remove the influence of electrical parasitics. The temperature dependence of the modulation response of a DFB quantum-well laser is examined by extracting the temperature-dependent differential gain, injection efficiency, carrier lifetime, and other temperature-dependent factors. To study the cross-gain modulation response, a new rate equation model is developed for cross-gain modulation with an optical pump at 1.48 mum and 1.538 mum. Optical modulation experiments are performed to demonstrate the cross-gain modulation response, including pump-wavelength dependence and temperature dependence. The extracted differential gain, carrier lifetime, and other parameters are compared with those obtained from the earlier high-speed modulation experiments, and the similarities and differences are explained in terms of the newly developed rate equation model for cross gain modulation. The most significant bandwidth-limiting factors, primarily the differential gain, are discussed.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD