Proposal of a Design Principle of Multilayer Media

We propose a design principle of stacking-type super-multilayer media in this paper. By the use of an original high-transmittance and high-recording-sensitivity recording material, bismuth–germanium–oxide, the recording layers of a 10-layer super-multilayer disc can be designed using only two types of recording layer. This leads the conventional super-multilayer media structure to a much simpler structure with only two thicknesses of spacer layers while maintaining a satisfactory signal quality on the farthest layer from the incident laser beam, where signal fluctuation due to coherent crosstalk is the strongest. The above design principle will greatly contribute to the reduction of the cost of super-multilayer media.