Sumitaka Maruyama

New write shift compensation method modified for optical disk systems to which partial response maximum likelihood (PRML) detection is applied

A new write shift compensation method is proposed in this paper. The method is suitable for an optical disk system which adopts partial response maximum likelihood (PRML) detection, and it can optimize adaptive controlled writing pulses even under severe inter-symbol interference (ISI) conditions to reduce detection errors. This advantage is attributable to the use of the Euclidean distance as the estimation index of the mark edge shift error. The effect is confirmed by the experimental results for blue laser systems.

Computational analysis of electric field distribution in dual-layered phase-change disc

We developed a Finite-Difference Time Domain (FDTD) Method based simulator that can analyze Dual-Layered phase-change disc structure. Because of a substrate thickness error, it is necessary to consider spherical aberration. The electric field distributions have been calcuated on Single-Layered and Dual-Layered phase-change discs. We found differences between the electic distributions focused on a groove and on a land. These calculation results can explain the corresponding experimental results clearly.

A new write shift compensation method modified for optical systems to which PRML detection is applied

A new write shift compensation method modified for optical disk systems to which PRML detection is applied is developed. The compensation method achieves optimization of all writing pulses adaptively. The compensation parameters are calculated to minimize the probability of detection errors. The experimental results certify that the ch.bER is improved using this method.