Preheating for laser diode drivers

Reduction of capacitor ESR in a laser driver by use of low-level discharge current pulses The ESR (equivalent series resistance) of the storage capacitor 3 in a pumping laser diode driver circuit may be too high to allow operation of the pumped laser in polar regions or at high altitude. To address this problem load pulses may be drawn from the capacitor 3 to raise the capacitors temperature by internal dissipation. The laser diode 5 may be used as a pumping energy source for a laser rod, the heating pulses being insufficient to initiate a laser discharge in the rod. The subcritical heating pulses also warm the laser rod and the laser diode. If the measured ESR is too high, or if the ambient or capacitor temperature is too low,