Blue phase change recording at high data densities and data rates

For the DVR system with the use of a blue laser diode (wavelength 405 nm) we developed (12 cm) discs with a total capacity of 22.4 GB. The land/groove track pitch is 0.30 mum and the channel bit length is 87 nm. The DVR system uses a d = 1 code. These phase change discs can be recorded at continuous angular velocity (CAV) at a maximum of 50 Mbps user data rate (including all format and ECC overhead) and meet the system specifications. Fast growth determined phase change materials (FGM) are used for the active layer. In order to apply these FGM discs at small track pitch special attention has been paid to the issue of thermal cross-write. Finally routes towards higher capacities such as advanced bit detection schemes and the use of a smaller track pitch are considered. These show the feasibility in the near future of at least 26.0 GB on a disc for the DVR system with a blue laser diode.