Lifetime testing of laser diode coolers

The purpose of this paper is to report life-testing results of a copper micro-channel cooler [MCC] for high power diode laser [HPDL] bars. The testing is being done on MCC's with 3 different internal designs at three different flow rates, ranging from 0.2 l/min. to 0.5 l/min. Water conductivity is kept constant at 5 micro-Siemens/cm, and the water temperature is maintained at 25C. The MCC's do not have a voltage applied to them. The test is ongoing, but results up to 15,000 hours will be reported. Preliminary results indicate that lifetimes over 20k hours can be achieved with proper control of conductivity, and that flow rate and internal structure are secondary considerations compared to water quality.