Threshold drop of the differential resistance of stripe quantum-well InGaAs\/GaAIAs lasers

An investigation was made of the differential current—voltage characteristics of low-threshold lasers based on InGaAs\/GaAIAs quantum-well heterostructures with a strained active layer. The investigation was extended to nonlaser diodes made of identical heterostructures. The attainment of the lasing threshold was accompanied by a negative drop of several ohms in the differential resistance of a diode. This effect was in agreement with a simple model of the junction effect. Quenching of the lasing resulted in an abrupt increase in the voltage across a diode (by tens of millivolts). These abrupt changes in the resistance and voltage were correlated with a jump in the output power.