Temperature dependent loss and overflow effects in quantum well lasers

We report a detailed study of the temperature dependent internal loss in 1550-nm quantum well lasers. Measurements of lasers with different cavity lengths as well as of lasers with modified facet reflectivities are presented. The internal loss is found to be mainly associated with intervalance band absorption and to include contributions from confined as well as unconfined carriers with the latter dominating at elevated temperatures. Measurements are consistent with calculations based on a detailed carrier injection model. Threshold current density dependence on temperature and on cavity length as well as photon density dependent internal losses are also addressed.<>