Abstract
In the dissertation, stability analysis and four-wave mixing (FWM) analysis are applied to investigate the characteristics of the relaxation oscillation of the quantum dot (QD) and the quantum well (QW) semiconductor lasers and their responses to the weak external perturbation, respectively. The FWM analysis can also be utilized to extract the intrinsic parameters of the semiconductor lasers, which apparently influence the dynamical behaviors. Through the modifications of strong external perturbations on the intrinsic parameters, the dynamical behaviors of the lasers can be investigated thoroughly. The linear stability analysis has been applied on the solitary and injection-locked lasers of QD and QW structures. By deriving the characteristic equations from the small internal fluctuations, the relaxation frequencies and the damping rate can be obtained. From the damping rates of the lasers with different bias currents, linewidth enhancement factors, injection strengths, and detuning frequencies, the QD lasers show better stability than the QW lasers. Moreover, the stability and excitability of the QD laser subject to optical feedback are also numerically discussed. To investigate the responses on small external perturbations in the FWM analysis, the rate equations of the solitary and injection-locked lasers of QD and QW structures are derived for the analytical solutions. Moreover, the FWM mixing analysis on the QD lasers subject to optical feedback is also derived. All the analytical models are carefully verified with the numerical simulations. FWM analysis has been applied on a QD laser to simultaneously obtain the linewidth enhancement factor and other intrinsic laser parameters. By fitting the experimentally obtained regenerative and amplitude modulation spectra at different detuning frequencies with the respective curves analytically calculated from the rate equations, parameters including the linewidth enhancement factor, the carrier decay rate in the dots, the differential gain, and the photon decay rate can be determined simultaneously under the same operating conditions. The sensitivity and accuracy of the parameter extracted by the FWM analysis are presented. Moreover, how each parameter alters the shapes of the regenerative and amplitude modulation spectra is also discussed. Moreover, a simplified rate equation model is utilized for the FWM analysis on QD lasers subject to optical injection. The regenerative and amplitude modulation spectra of the QD laser with different intrinsic laser parameters and external injection conditions are investigated. By curve fitting the regenerative and amplitude modulation spectra experimentally, the intrinsic laser parameters of a commercial single-mode QD laser under different injection conditions are extracted. The linewidth enhancement factor at different injection levels and detuning frequencies are shown, where a reduction of about 40% from its free-running value is demonstrated. By increasing the injection strength, the linewidth enhancement factor can be further reduced to minimize the chirp in optical communications. To comprehensively investigate the characteristics of QD laser subject to external perturbations, the model for the FWM analysis on the QD laser subject to optical feedback is also developed analytically. The modifications with different feedback conditions on the regenerative and amplitude modulation spectra are discussed. Also, how the regenerative and amplitude modulation spectra vary with each intrinsic parameter is discussed. Based on the theoretical prediction, we successfully extract the intrinsic parameters of the QD laser subject to optical feedback experimentally and the linewidth enhancement factor is found to increase with optical feedback.