Extremely high optical power density emission was achieved with an AlGaAs "window structure" laser in CW operation as well as pulsed operation by increasing the threshold of the catastrophic optical damage (COD) on mirrors. A Zn diffused "window stripe" laser consists of the Zn diffused p-type light emitting region with low effective energy gap in the central part and the n-type window regions with high effective energy gap at both ends of the cavity. The maximum available optical power in pulsed operation was at least one order of magnitude higher than the COD threshold in conventional structures. 80 mW optical power in CW operation was achieved in the Zn diffused window stripe laser with a 5 μm wide stripe. Furthermore, gradual degradation due to the photoenhanced mirror oxidation has been reduced significantly under long term CW operation.