Switching between generation of two quantum states in quantum-well laser diodes

Abstract

The dynamics of emission spectra in semiconductor quantum-well lasers generating from two quantum states have been experimentally studied. In the case of electric pumping with 100-ns pulses, the lasing via transitions from the ground state is switched off and the emission from an excited state is switched on within 10–50 ns after laser turn-on. The switching is accompanied by a dip in the intensity of lasing, the duration of which depends on the pumping pulse amplitude. The observed phenomenon is explained in terms of gain clamping and redistribution of the carrier concentration between the ground and excited states.