The laser diode has a reverse breakdown voltage of only 2V. Try putting a Schottky diode in reverse parallel to the laser diode. several dozens of hours, which is applied to all fabricated diodes of a model, mainly to identify and remove those which would not reach the required performance or the specified lifetime, e. This is evidence that its burnt out right? Its a diode, so current should only be able to go in one direction? Thanks! Laser diodes do NOT generally tolerate reverse. Many laser diode packages incorporate an internal monitor photodiode which may be used in a feedback loop to maintain constant optical output power from the laser under varying temperature conditions and as its performance slowly degrades over time. If I were doing this I would not use R1, and monitor the current produced by. Laser diodes typically fail as the result of two distinct damage mechanisms: One of the damage mechanisms is optically related, and occurs when the laser diode is producing light (referred to as “lasing”), and the optical energy density exceeds the laser diode's integral mirrors' reflective. For example, this is how ESD protection diodes (TVS diodes) fail when driven excessively into reverse bias by strong voltage pulses. Unless this current is limited.