Feasibility Study of Ge-Sb-Te Phase-Change Optical Disk Medium for One-Pass Overwrite Digital Audio Recording

A phase-change optical disk medium utilizing a Ge 12 Sb 39 Te 49 memory film showed characteristics suitable for one-pass overwriteable digital audio disk system at a low linear velocity of 1.3 m/s. Applying the multipulse recording method, the eight to fourteen modulatlon (EFM) signals were successfully overwritten using only one laser beam with a small block error rate (BLER) of <50 counts/s. The laser irradiation power was typically 13 mW for the peak power level and 7 mW for the bias level. The available cycle number was observed to be more than 10 4 cycles with a practical sufficient laser power tolerance of + / -20%.