Multi-level data storage system using phase-change optical discs

Calimetrics Inc. has worked previously on multi-level (MIL) ROM systems to prove that this concept could be implemented using existinand manufacturing infrastructure. Pit-depth modulation (PDM) technology was the result and simple proof-of-concept systems were created for both CD and DVD-ROM. Since then, Calimetrics Inc. has been focusing on multi-level RW phase-change systems, given the greater business interests that were exhibited for the rewritable market. We report here on progress to date on multi-level CDRW technology and look forward to its application to DVD-based RW systems.