High-power blue-violet laser diode fabricated on a GaN substrate

We have successfully fabricated blue-violet laser diodes, consisting of nitride-based semiconductors, with both high-power and low-noise characteristics on GaN substrates. These laser diodes have a ridge waveguide structure with a dielectric current blocking layer. By improving the crystal quality of the grown materials and optimizing the optical confinement in the device, a kink level as high as 250 mW has been achieved. Optimized optical confinement is also assumed to result in far field patterns without any additional peaks. In addition to this, since the threading dislocation density at the active layer below the ridge portion is reduced to less than 105cm-2, these laser diodes have been operating reliably for more than 1000 h with a light output power of 100 mW at 60°C under pulsed operation. We have also confirmed that these laser diodes have a noise level as low as -130 dB/Hz, which meets the requirement for practical use, for a light output power of 5 mW. These laser diodes are expected to enable dual layer recording in nextgeneration, large-capacity optical disc systems using blue-violet laser diodes.