Static and dynamic properties of vertical-cavity surface-emitting lasers.

摘要

In this work, several different aspects of the static and dynamic properties of vertical-cavity surface-emitting lasers (VCSELs) are investigated. First, the spontaneous emission spectrum of a VCSEL is measured from the fiber-coupled side emission, and the integrated spontaneous emission power of the VCSEL is observed to increase significantly above threshold as a function of current. The material gain spectra of the quantum-well active region is then modelled over the same temperature range, and results show that material gain degradation due to temperature can account for a significant amount of the observed increase in threshold carrier density.; The measurement of the cavity emission spectrum, defined as the top emission spectrum divided by the side emission spectrum, is presented. A propagation-matrix model, which includes a spontaneous emission source in the active region, is developed to simulate the observed results. The observed transmission peak shifting is attributed to the temperature-dependent refractive index and layer thickness in the DBR layers which are implemented in the model.; The effects of spatial hole burning are investigated in selectively oxidized VCSELs of various aperture sizes. The mode formation and light-current curves exhibit mode competition between modes of the same polarization and different polarizations. The large-signal modulation response of a two-mode oxide VCSEL is measured and modelled using a rate-equation model which includes spatial hole burning effects. Good agreement is achieved between experiment and theory and the importance of spatial hole burning in the transient response is validated.; Fiber-induced optical feedback is studied by measuring the static properties of an oxide VCSEL as a function of fiber position and correlating the data to theoretical results using a vector mode-matching method which includes the fiber in the modelled structure. A novel method for estimating the linewidth enhancement factor in VCSELs is developed from the matching of theory and experiment. Two-mode competition in the VCSEL under feedback is also investigated.