Modeling and design of tracking servo signals for 2X and 4X substrates

The design of tracking grooves and pre-formatted data on the disk substrate is described for 2X and 4X generation optical media. A unique aspect of this study is the identification of regions in the design space of extreme parameter sensitivity. Avoiding these regions can lead to a more robust manufacturing design. In particular, for both 2X and 4X it is important to have pit widths that are a suitably small fraction of the width of the lands.