Efficient vertical-cavity lasers

Recent experimental and theoretical results from strained InGaAs/GaAs quantum-well vertical-cavity surface-emitting lasers indicate that relatively high-power, efficient devices are possible. On 10 m square devices cw output powers of more than 3mW at room temperature and 0.4 mW at 100°C are observed. Broad-area, 100 m diameter devices gave pulsed outputs of over 0.5 W and 60 m diameter devices provided more than 12 mW cw. The device parameters have been modelled and found to be consistent with theoretical predictions. The results generally indicate that considerable device improvements are still possible by reducing internal losses, series resistance and voltage and improving heat sinking. With current internal loss levels 30 cm^–1, three InGaAs quantum-wells have been found to be optimum.