Abstract

In order to achieve high density recording in a magneto-optical disk, much attention has been paid to reduce thermal interference between the recording pulses¹,². This is because thermal interference causes the variation of the recorded domain size and shape². The domain size and shape fluctuation introduces peak shift and amplitude variation of the optical readout. This effect is significant³ when the separation between the data bits is small in a high density recording medium. For a disk drive using domain-edge recording, the peak shift introduces timing jitter relative to the timing clock pulse. In a sampled servo disk drive, the amplitude variation results in deterioration of the margin of the amplitude threshold detection⁴. The timing jitter in edge-recording disk drive and erosion of amplitude threshold detection margin in a sampled servo disk drive both result in carrier-to-noise ratio reduction and thus larger bit error rate of the system. In this paper, a sampled servo drive is used to study the readout amplitude variation due to thermal interference in successive recording pulses. A simple compensation technique is demonstrated to achieve uniform optical readouts of the recording data bits in successive recording pulses.

© 1994 Optical Society of America