Abstract
GaN-based blue-violet laser diodes (BV-LDs) have rapidly progressed for use of the next-generation optical storage system. The main issue to practical use has been establishment of reliability for the device. In other words, the reduction of the dislocations in GaN-crystalline structure was the most important issue. The recent development of a low-dislocation-density GaN substrate allows us to fabricate high-quality BV-LDs. In this paper, we report on the structure and basic characteristics of BV-LDs grown on a low-dislocation-density GaN substrate. Also, a hybrid three-wavelength laser diode was demonstrated for system compatibility with the conventional digital versatile disc (DVD) system as well as the compact disc (CD) system.
