Typical diode lifetimes are in the range of 25,000 to 50,000 hours. These degradation sources. In general, high temperature testing is used to determine LED and laser diode lifetimes, even though laser diode failure mechanisms are more sensitive to increases in current density. As a measured parameter of degradation, the current density is of great significance when searching for failure. However, there are reasons for running below 100% duty in order to increase the potential diode longevity. Based on the observed failures assuming a certain failure statistics the Mean Time To Fa lure (MTTF) can be determined.