Random Population Model for Self Pulsation in Single-Section Quantum-Dot Lasers

A new mechanism of self-pulsation in single section Fabry-Pérot (F-P) quantum-dot (QD) lasers is studied in this letter. Since Fermi-Daric statistics are not readily applicable to QD lasers for picosecond pulse generation, we use a random population model to simulate single-section QD F-P lasers. It is demonstrated that some QDs contribute as gain media, while others can still be absorptive, even though the overall device is biased above lasing threshold. This can lead to pulse generation without the typical nonlinear effects, such as four-wave mixing, Kerr nonlinearity, and spatially inhomogeneous current distribution, previously reported in single section self-pulsating semiconductor lasers.