Dynamic tracking control in an optical recording system by

Abstract

An apparatus and method for providing dynamic tracking error detection and control in an optical recording system in which an incident beam records data on a medium in the form of marks. A diffraction-based mark formation effectiveness (MFE) signal is generated by monitoring a reflected write signal in part of the return beam aperture or in multiple zones of the return beam aperture and is indicative of a characteristic of the marks formed on the medium. A position signal is generated to provide an indication of cross-track movement of the incident beam relative to a tracking structure on the medium. The tracking structure may be a wobbled groove on an optical disk recording medium. Variations in the diffraction-based MFE and position signals are correlated to provide a dynamic tracking error signal (TES). The diffraction-based MFE and position signal variations may be correlated by, for example, multiplying the two signals together in a multiplier circuit, or using the position signal to control application of the diffraction-based MFE signal to particular inputs of a signal difference circuit. The dynamic TES may be utilized in a servo loop with or without a push-pull signal or other conventional tracking signal.