Concepedia

Abstract

The partial response and maximum likelihood (PRML) detection method is promising as a detection scheme for next-generation optical disk systems. For application of the PRML detection, a new value is required in order to evaluate signal quality instead of jitter, which is used in current optical disk systems. For this requirement, we developed a new evaluation method that is based on the principle of the PRML detection. This evaluation value is defined as the occurrence probability of miss-detection in the PRML detection. We evaluated the proposed method using a simulated waveform and an experimental waveform for two systems. Each system consists of a phase change disk with cover layer thickness of 0.6 mm and 0.1 mm, a blue laser with wavelength of 409 nm and 407 nm and an objective lens with numerical aperture of 0.65 and 0.85, respectively. As a result, we confirmed the validity of the proposed method for each system.