Investigations of the dynamics of the far-infrared p-Ge laser emission
reveal strong periodic soliton-like intensity spikes with less than 1
00 ps duration. We interpret these spikes as self-mode-locking of p-Ge
laser modes. The effect becomes more pronounced when a GaAs/AlGaAs/In
GaAs quantum well structure on a semi-insulating GaAs substrate is ins
erted into the laser cavity. (C) 1998 American Institute of Physics. [
S0003-6951(98)01647-7].