As multimedia becomes more common in computer usage, stored information is changing from still images to moving pictures. As a result, higher density storage is required in optical disk systems. One method of increasing recording density is to narrow the track pitch; however, this increases crosstalk from adjacent tracks during playback. Several methods of overcoming this problem have been studied, such as land/groove recording1) and crosstalk canceling using a three-beam optical head2). However, these methods require either additional disk fabrication or complicated optical heads.