  The readout systems for the ATLAS silicon trackers and liquid argon
calorimeters utilize vertical-cavity surface-emitting laser diodes to
communicate between on and off detector readout components. A number of these
VCSEL devices have failed well before their expected lifetime. We summarize the
failure history and present what has been learned thus far about failure
mechanisms and the dependence of the lifetime on environmental conditions.

Instrumentation and Detectors;High Energy Physics - Experiment