DESIGN CONSIDERATIONS FAR HIGH-POWER GAINP ALGAINP UNSTABLE-RESONATORSEMICONDUCTOR-LASERS/

Simple expressions are derived to evaluate the lasing condition and po wer 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 o ptimum 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 m aterials. A set of high-power (1-W, double-mirror, pulsed) 660-nm wave length 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 curr ent of 3000 mA.