High storage density optical disks using pit-edge recording on PbTeSe thin film

Pit-edge recording, where, the leading and trailing edges of the pit correspond to code-data 1, can achieve about one and a half times more bit density than that of pit-position recording. Using pit-edge recording with an effective write-read compensation scheme, we have achieved high linear density of 0.63 microm/bit on a PbTeSe ablative type optical disk. The write compensation is able to cancel pit expansion caused by thermal diffusion and surface tension of the recording film. We also confirmed the possibility of 0.50-microm/bit recording with an advanced compensation scheme on a PbTeSe optical disk. The corresponding user data capacity is ~1 Gbyte/side on a 130-mm diam optical disk.