Reduction in Operating Current of High-Power 660 nm Laser Diodes Using a Transparent AlGaAs Cap Layer.

We have introduced a transparent AlGaAs cap layer instead of a conventional GaAs cap layer into high-power 660-nm-band-laser diodes with weaker optical confinement in the perpendicular direction, since this structure enables us to weaken the optical confinement without increasing the internal loss for a real index-guided structure. The fabricated laser diodes have demonstrated reduced operating current of 150 mA at 100 mW and increased maximum light output power of 200 mW under the pulsed condition. An aspect ratio of 1.5, which is the smallest of all 660-nm-band high-power laser diodes reported to date, has also been achieved. These laser diodes have been operating stably under the pulsed condition for nearly 2000 h at 60°C with a light output power of 100 mW, which is also the highest of all real index-guided 660-nm-band laser diodes reported to date.