Abstract:The carrier-photon rate equation model of quantum dot laser was derived based on the two energy states system. By analyzing the transient response and modulation characteristics of quantum dot laser, its dynamic characteristics were obtained. The dependence of quantum dot laser output photon density on the inject current was discussed. With increasing the injection current, both the delay time and the relaxation process were shorten, but both the relaxation oscillation frequency and the peak and steady-state power of output photon increased, which means that the modulation bandwidth of quantum dot laser can be broaden by appropriately increasing the inject current. Based on the small-signal modulation analysis, it is found that the maximum modulation frequency of quantum dot laser is an order of magnitude higher than that of the conventional semiconductor laser. Then it is proved that the quantum dot laser has much better high frequency modulation characteristics.
