Laser Diode Characterization

Damage and degradation mechanisms are depicted at another wiki chapter, but so much be said: Testing equipment will require special attention to the power source and the ESD protection of the devices. The bare laser diodes chips are very sensitive to electric damage (both current spikes and reverse current) arising from inadequate power sources or from ESD. Thank to their low inherent impedance they are prone to quickly react to current changes. The improper choice of voltage-controlled power sources are a surprisingly frequent cause of laser damage. Power sources for laser diode operation must always be current controlled instead and carefully designed not to produce any current spikes over the specified current limit. ESD protection is another topic of paramount importance that must be accounted for at every step of the laser diode handling.

During the manufacturing of the laser diodes, this is likely the first time that laser radiation risks need to be taken care of. The testing equipment for laser diodes must be shielded accordingly, not allowing stray laser radiation to exit the machine and pose a health risk. For this purpose also interlocks must turn off the laser power source if the doors or encasement of the testing equipment open. OptoSystem’s testing equipment fulfills laser class 1. Otherwise further shielding and warning lamps, in-depth operator risk assessing training and other measures might be necessary.