New types of the optical mask to suppress the adjacent track crosstalk

Abstract

To achieve a narrower track pitch, say ,0.85 μ m which is proposed for 5.2Gbyte/130mm MO, suppression of the adjacent track crosstalk (ATC) will be one of the key technology for the optical memories. Several methods have been proposed for the suppression of the ATC such as land/groove recording. Dobashi 1) et.al. have proposed one method to reduce the ATC by inserting a shading band in the optical path. Shimano 2) et. al. have also reported that optical filterings are effective to reduce the ATC without degradation of the signal amplitude of the center track. Although their filters can indeed reduce the ATC from the long marks such as 6T,7T and 8T, the ATC relatively increases after the insertion of the filters with regard to short marks such as 3T and 4T. In this paper, we propose new types of the optical mask which can reduce the ATC from the long mark signals with suppressing the increase of the ATC from the short mark signals to negligible level.