Surface roughening of recording media and readout performance of phase-change optical disk

Abstract

Scaling characteristics of the surface roughening of the phase-change optical media have been investigated. Studies have shown that the variation-correlation function of the surface profile of recording media follows an asymptotic power law. The influence of the film surfaces with different roughness on the readout performance of the optical media has been investigated based on a scalar diffraction model. The results show that only one roughness parameter cannot reflect the responding readout properties of a phase-change optical disk such as signal noise and jitter due to the surface roughening. Fractal Brownian motion is applied to simulate the scaling characteristics of the surface roughening. Influence of the surface roughening with different Hurst exponents on the readout performance of the optical media has been studied. Results of the numerical calculation from both simulated and physical surfaces of the phase-change media show that the surface roughening with a lower Hurst exponent will cause a higher deterioration of the detected signals. Therefore, the fractal method provides an effective approach to the failure analysis of the optical phase-change disk.