Abstract
Mechanisms of carrier sweep-out in tandem InGaN multiple-quantum-well self-pulsating laser diodes were investigated. Laser diodes showed self-pulsating characteristics without significant change in the light output–current (I–L) characteristics when an electric field high enough was established in the saturable absorber by the applied reverse bias. Improvements in the design of the band-energy profile allowed a substantial reduction in the bias required for self-pulsating operation. These results indicate that carrier lifetime can be controlled by the electric field in the saturable absorber and that band-energy profile engineering is effective for the reduction of carrier lifetime.