The aging behavior of edge emitting laser diodes based on GaAs/AlGaAs is investigated by comparing devices with facets that are alternatively cleaved or dry etched and consecutively treated with H2S. In this work we demonstrate that an in situ exposure to H2S gas is not sufficient to prevent ageing but an additional plasma treatment is rather required to obtain comparable ageing results to lasers with cleaved facets. (C) 2004 American Vacuum Society.