Relationship between cross-talk and birefringence on 1.3-GB-130-mm magneto-optical disk

It is important to control the cross-talk that decreases the write/read window margin on the 1.3 GB - 130 mm MO disk, since the recording track is adjacent to the embossed pits of the header. We think this cross-talk is caused by two effects, one is the diffraction of the reflected light by the adjacent embossed pits and the other is `micro-birefringence' which exists in a local stress field around the embossed pits. We analyzed theoretically the relation between the micro-birefringence effects and macro-birefringence in a PC substrate, using a simple model of the micro-birefringence. The result shows that the cross-talk value depends on both vertical and in-plane macro-birefringences of the substrate. The combinations of the vertical and in- plane birefringences that make the maximum MO signal, don't make minimum cross-talk. Since the cross-talk is enhanced by the macro birefringence, only a narrow region of the vertical and in-plane birefringence are available to get the high quality of the MO signal-to- cross-talk ratio.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.