A single laser diode bar design, based on the AlGaAs material system, has been developed for high power, high reliability operation at a variety of CW and QCW operating conditions. The bar has a cavity length of 750 micrometer and a fill factor of 40%. Typical CW operation has a threshold current of approximately 10A and a conversion efficiency of greater than 45% at 40W. A variety of lifetests have been conducted at both CW and QCW operating conditions from the same bar design. On- going 3000 hr CW operation at 45C and 40W shows an extrapolated median lifetime (20% current increase) of 16,500 hrs at 45C or approximately 50,000 hrs at 25C (with 0.45eV activation energy). On-going 3000 hr QCW operation at 60C/60W and 35C/100W, with a pulse width of 200 microseconds and a duty factor of 2%, shows a median lifetime of approximately 10 billion shots and approximately 5 billion shots, respectively. In addition to single bar operation, this bar design can be stacked in various 2-D configurations. A 4 bar linear stack operating at 160W CW and a 6 bar vertical stack operating at 240W CW have been developed with superior performance. Results for high duty and low duty QCW stacks will also be presented.