Abstract: A diode laser apparatus is heated at its junction by operating the diode at subthreshold current levels. A special bi-level pulse forming network (PFN) improves the efficiency in preheating the diode during non-operating or non-light producing modes along with the ability to supply the necessary drive during operating or light producing modes. This is accomplished by operating the laser diode at subthreshold or non-light producing current levels, which heats the diode at the diode junction directly where the heat is needed, and by the use of a bi-level pulse forming network which transfers the heating energy to the diode junction with high efficiency.

Abstract: A laser apparatus or system is provided including a driving mechanism for driving a pulsed semiconductor laser which injects optical energy into a lasing medium. A digital filter is employed to adjust the time duration or pulse width of drive pulses which excite the semiconductor laser. In this manner, the irradiation of the lasing medium is adjusted by pulse width modulation of the driving current in the semiconductor laser. The laser apparatus employs a sampled output, digitally filtered, negative feedback signal to drive the semiconductor laser. This structure has the effect of making the semiconductor laser responsive to changes in the laser system or to undesired degradation in the laser system. The laser apparatus compensates for the inherent time lag in laser output power energy during initial startup of the laser.

Abstract: A laser apparatus is provided in which a laser diode is driven with a plurality of drive pulses to generate a plurality of first laser pulses. Each first laser pulse occurs during a respective window and has a predetermined pulse width determined by a corresponding drive pulse. An electronic shutter which intercepts the laser beam is then opened in response to a trigger signal to permit a second laser pulse to be emitted from the laser rod during each window. The laser energy output of each of the second laser pulses from the laser rod is continuously monitored on a window by window basis to determine if the energy output of each of the second laser pulses exhibits a predetermined desired value. The energy output of the second laser pulse observed during each of the windows is then reported as a respective energy report signal set for each of the windows.