In this paper, the nonlinear rate equations governing a quantum dot laser is used to simulate the transient as well as the steady-state behaviors of the laser. Computation results show that the rate equations are capable of simulating true behavior of a quantum dot laser. Then, the pump rates of the rate equations (which show indirect electrical pumping of the quantum dots through a wetting layer) are changed so that they can show direct electrical pumping of the quantum dots. Simulation results predict that a quantum dot laser with direct pumping has much lower threshold current than the indirect one. It is also shown that duration time of the transient regime to reach steadystate operation is shorter in direct pumping.
