Internal Q-switching in semiconductor lasers: high intensity pulses of the picosecond range and the spectral peculiarities

Optical pulses of ~100 ps duration, and ~10² W power were obtained from the industrial single heterostructure lasers with a standard pulse generation power of ~10 W in the internal Q-switching mode. Temporal and spectral analyses allow three components to be distinguished in the laser optical pulses: ordinary delayed pulses of large duration at energies considerably lower than the energy gap, short optical pulses caused by the gain-switching effect at higher energies, and short optical pulses at the end of the current pulse (Q-switching mode) at the highest energies. A model is proposed involving band tail states as a saturable absorber causing large delays