Abstract

In recent years, mode-locked quantum-dot (QD) lasers have shown great promise as compact ultrafast laser sources [1]. QD materials exhibit a set of discrete energy levels, and in this context we have previously shown the potential of generating ultrashort pulses in a QD laser, involving either the ground state (GS) or the excited state (ES) spectral bands [2]. However, previously the two mode-locking regimes did not coexist, and it was necessary to change the electrical bias conditions in order to switch between one to the other. Very recently, dual-wavelength mode-locking was reported for a single-section InP-based QD laser, with pulses being generated simultaneously at 1543 and 1571nm. However, these spectral bands are not ascribed to the ES/GS transitions and due to the absence of a saturable absorber, the mechanism for this pulsed regime is not yet fully understood.

© 2009 IEEE