SHORT WAVELENGTH MO RECORDING: SYSTEM NOISE ISSUES AND PERFORMANCE OPTIMIZATION

Abstract

Optical recording at 488 nm using optimized CoPt multilayer media is described. Large mark CNR values of 62 dB are achieved by ensuring that system noise is dominated by the media noise component through a combination of media desensitization, read power optimization., and, elimination of the groove noise component which usually dominates the system noise. The results indicate that it is generally not possible to decrease the laser power requirements when utilizing a small recording laser spot size despite the increased power density because of these noise constraints. Further, because of a decreased detector sensitivity at blue recording wavelengths, further desensitization beyond that necessary to compensate for the increase power density is required when shorter wavelengths are used to achieve a smaller spot size.