Analysis of Gain-Switching Characteristics Including Strong Gain Saturation Effects in Low-Dimensional Semiconductor Lasers

The effects of gain nonlinearities on gain-switched short-pulse-generation characteristics are analyzed via rate equations assuming a nonlinear-gain model including a gain saturation parameter g s to quantitatively describe the strong gain-saturation nonlinearity in low-dimensional semiconductor lasers at high carrier densities. It was found that the minimum pulse width and the delay time are mainly determined by g s rather than a differential gain coefficient g 0 and a gain compression factor ε. By tracing the temporal evolution of carrier density, photon density, and material gain during gain switching, distinctly different effects of g s, ε, and cavity lifetime τp on pulse generation were clarified.