Abstract

Substrates for magneto-optical disks are produced economically and efficiently by injection molding of polycarbonate plastics. Unfortunately, most plastics are birefringent, with different refractive indices in the plane of the disk (lateral birefringence) and perpendicular to the plane of the disk (vertical birefringence). One manifestation of media birefringence is the existence of a focus offset between the two distinct best-focus positions for data detection and tracking. This focus offset degrades overall system performance as the compromise focus position between the two best-focus points reduces the operating margin of the individual data and tracking channels. We present detailed numerical modeling results on the role of substrate birefringence in causing this focus offset.

© 1993 Optical Society of America

Temperature dependence of the birefringence of optical-disk substrates

Timothy D. Goodman, Ronald E. Gerber, and M. Mansuripur
Appl. Opt. 35(16) 3031-3038 (1996)

Effects of substrate birefringence on focusing and tracking servo signals in magneto-optical disk data storage

Satoshi Sugaya and M. Mansuripur
Appl. Opt. 33(22) 5073-5079 (1994)

Characterization of a novel focusing/tracking technique with increased feedthrough immunity for optical-disk applications: the double-astigmatic method

Bruce E. Bernacki, Keith Bates, M. Mansuripur, Delbert Hansen, and Daniel Cisneros
Appl. Opt. 32(29) 5789-5796 (1993)

Subtle effects of the substrate in optical disk data storage systems

Timothy D. Goodman and M. Mansuripur
Appl. Opt. 35(34) 6747-6753 (1996)

Effects of substrate birefringence and tilt on the irradiance and phase patterns of the return beam in magneto-optical disk data storage

Ronald E. Gerber and M. Mansuripur
Appl. Opt. 34(22) 4780-4787 (1995)