Magnetically induced super resolution for high-density optical disk systems

The transition jitters of a Double-masked Rear Aperture Detection (D-RAD) readout werecalculated as a function of defocusing, disk tilt and recording mark width. The modelling resultssuccessfully explain our experimental results. Large jitter tolerances and a low byte error rate were obtained using 0.3 tm bit length recording. 1. INTRODUCTIONMagnetically induced super resolution (MSR) in magneto-optical (MO) disks using exchange- coupled magnetic multi-layer film have been previously reported'6. A portion of the focused spot is optically masked for the readout of the MO signal. The effective spot size after masking is much smallerthan that of the focused spot. Therefore super-resolution is realized.Various types of the MSR methods have been developed to achieve super-resolution. Among thesemethods, D-RAD has an advantage as it achieves a higher linear-density readout, because the width of theeffective spot in the tangential direction is significantly reduced by double masks. Using this method the