Hun Seo

Phase change optical media with time-shifted multipulse write strategy for 1X-2X dual speed Blu-ray disc system

We have developed phase change optical media with appropriate write strategy for 1X-2X dual speed Blu-ray Disc system and for the future high speed phase change optical data storage. For recording layer, eutectic-based Ge(Sb70Te30)+Sb material was used and Sb/Te ratio and Ge content were optimized to obtain proper erasability and archival stability of recorded amorphous marks. The recording layer is wrapped up in GeN interface layers to obtain reasonable overwrite cyclability and higher crystallization speed. In addition, we designed appropriate write strategy so-called time-shifted multipulse(TSMP) where the starting positions of multipulse parts are shifted from reference clock. With this write strategy, the overall jitter characteristics of the disc was improved and especially we found that trailing edge jitter was improved much more than leading edge jitter. Thus feasibility of 1X-2X dual speed applicable Blu-ray Disc and its write strategy was demonstrated.