Spatial Profiling of Quantum Dot Lasers

The unique electronic structure of quantum dot based semiconductor lasers leads to significant differences in lasing properties when compared to their quantum well counterparts. In particular, the total injected carrier population can be separated into two types: one that take part in lasing process, called resonant charge carriers and the other one that do not take part in lasing process, called nonresonant charge carriers. In this thesis, two methods are used to model injection profiled quantum dot lasers and examine the roles of resonant and non-resonant carrier populations. The first model is a rate equation approach, which is used to analyze the dynamical properties along the transverse section of the laser. The second model is a steady state beam propagation approach, which calculates both transverse and longitudinal carrier and field distributions in the laser. Numerical simulations on both models reveal the role of non-resonant carries in the appearance of a characteristic dip at the center of the near field intensity profile. Furthermore, these models reveal the occurrence of symmetry breaking in the near and far field intensity distributions at high injection currents. In addition, the steady state beam propagation approach uncovers non-uniformities in the non-resonant carrier profile along the longitudinal dimension. In addition to single emitters, this work also examines the possibility of phase-locking between two transversely coupled injection profiled QD lasers, where various types of phase relationships are identified. We compare the performance of single and double emitters by examining the beam focusing properties and evaluating M2 factor for various configurations.