Passive modelocking MIR quantum cascade laser incorporating self-induced transparency

摘要

In this paper, we discuss the passive modelocking of the Quantum Cascade Laser incorporating two thin absorbing layers over the gain medium. Based on self-induced transparency (SIT) effect in such structure, it has been demonstrated a potential modelocking by interleaving gain and absorbing layers. We propose here a simplified structure designed by a gain medium surrounded by two thin absorbing layers. To bring out the modelocked stability, we solve the Maxwell-Bloch equations for an open two-level system by the Finite-Difference Time-Domain method. As in the case of the interleaved structure, we find similar physical effects on the SIT modelocking in the presence of saturable absorber thin layers. The intensity and the duration of the generated pulses depend strongly on the saturable nonlinearity coefficient and also on the pumping ratio.