Technological Critical Points of InGaAsP/InP 1.3 μm Lasers as Evidence of 12000 Hour CW Operating Life Tests

Electro-optical characteristics evolution of InGaAsP/InP lasers after 12000 hrs life tests with respect to their technological - crystallographic critical points is analyzed. In particular it was found the Indium die-attach is more reliale than is thought; in addition, through dynamic thermal resistance measurements, it is possible to screen out badly soldered devices. Gold diffusion was a degradation process always present even if it was not always the main one. Specific crystallographic defects result in influencing the ageing behaviour both directly favouring pulse threshold current increase and indirectly promoting thermal process like gold migration. Different SEM technics (SEI, EBIC, EDAX) and Auger analysis are employed to analyze degraded devices.