Focus Error Analysis and Simulation in Multi-Layer Data Storage System

The key problem in multi-layer data storage readout system is how to separate the signal among different layers and avoid the crosstalk between the different layers. The adjusted Fuke prism method and dip incidence is used in focusing control of readout system. Since the practical requirements of fixing prism is higher, the variation of defocus signal with the prism fixing bias is analyzed and simulated in this paper. It is proved by theory and simulation that the focus error signal can be separated from each layer and be received by the detector with the consideration of fixing error and bias.