Suppression of Q-switching instabilities of passively modelocked semiconductor lasers by a passive electrical circuit

The elimination of Q-switching instabilities in passively modelocked monolithic semiconductor lasers by connecting passive electrical components to the absorber section is demonstrated. Suppression of Q-switching and Q-switched modelocking for a passively modelocked monolithic two-section quantum-dot tapered laser are achieved. In addition, extension of the modelocking operation range towards lower gain currents is accomplished, thus improving generation of ultrashort pulses. The suppression is attributed to the effective damping of low-frequency photocurrent fluctuations in the absorber section.