DESIGN CONSIDERATIONS FAR HIGH-POWER GAINP/ALGAINP UNSTABLE-RESONATOR SEMICONDUCTOR-LASERS

Simple expressions are derived to evaluate the lasing condition and power characteristics of unstable-resonator semiconductor lasers (URSL's). The gain-loss characteristics of several quantum-well materials are summarized and found to be important for URSL design considerations. To optimize URSL performance, the cavity length needs to approach an optimum value, which varies from similar to 300 mu m for an InGaAs/GaAs graded-index separate-confinement-heterostructure single-quantum-well (GRINSCH-SQW) to similar to 1000 mu m for GaInP/AlGaInP GRINSCH-SQW materials. A set of high-power (1-W, double-mirror, pulsed) 660-nm wavelength GaInP/AlGaInP URSL's with magnification of 2.5 were fabricated using focused-ion-beam micromachining technology. The brightness of a 300 mu m x 1500 mu m URSL approaches 320 MW cm(-2) Sr-1 at a pump current of 3000 mA.