CW HIGH-POWER SINGLE-LOBED FAR-FIELD OPERATION OF LONG-CAVITY ALGAAS-GAAS SINGLE-QUANTUM-WELL LASER-DIODES GROWN BY MOCVD

Data are presented on long-cavity 100-mu-m wide broad-stripe laser diodes that lase with a narrow single-lobed far-field pattern in continuous room-temperature operation. Diodes with a cavity length of 1250-mu-m emit a power of 200 mW per facet into a 2.5-degrees lobe (full width at half maximum). Short-cavity devices, on the other hand, (cavity length of 350-mu-m) lase with a continuously increasing number of lateral modes right from threshold, and exhibit a far-field divergence that is over 3 times greater than that of 1250-mu-m long diodes. Explanations for the effect of increasing cavity length on the field patterns of these devices are proposed, based on the measured increase in injected carrier diffusion length in long-cavity diodes and the influence of thermal waveguiding and mirror losses on intermodal discrimination.