Features of the watt-ampere characteristics of stripe-contact heterolasers

An experimental investigation was made of the watt-ampere characteristics of stripe-contact heterolasers. Under cw conditions, a sudden increase in the radiation power was observed for a negligible change in the pump current near the stimulated emission threshold. For some laser diodes, an abrupt increase in the radiation power occurred at currents substantially higher than the threshold value. Investigations of the near-field pattern and of the radiation spectra showed that the observed features of the watt-ampere characteristics were due to bleaching of the passive heterostructure regions. A general analysis was made of the differential external quantum efficiency of the stimulated emission as a function of the current.