High-peak-power room-temperature GaAs laser arrays

The current procedures that are employed in the design and fabrication of high-peak-power room-temperature GaAs laser arrays are presented. The methods of material selection and heat-sink preparation are illustrated. Specific mention is made of the laser-chip packing densities that produce effective laser-array brightness in the 100 kW/cm²region. Actual arrays have been constructed that produce 1 kW peak power with 400 amperes peak of modulator current at 1 kHz, or 600 watts peak at 300 amperes peak at 5 kHz. For modulator-current pulses less than 35 ns, these arrays can be expected to operate for 10¹⁰pulses. For field-lens apertures only a few inches in diameter, beam divergences from these arrays of only a few milliradians can be realized. Data relating the power output as a function of pulsewidth, repetition rate, and modulator current for several array configurations are presented. Differential quantum efficiency and overall power-efficiency data and curves are illustrated for typical diode and array configurations. The schemes employed to select and interface various optical components necessary to produce the desired beam divergences from reasonably sized apertures are discussed. Brief mention is made of the parameters of the laser-junction radiation densities necessary to maximize the array operating lifetime.