Propagation of the laser beam in optical disk data storage systems

Summary form only given. In a typical optical disk drive, the beam of a semiconductor laser diode is collimated, shaped, polarized, and then sent through an aberration-free, high-NA lens to be focused on the "active" surface of an optical disk. The quality of the beam must remain very high throughout the entire optical path. Small amounts of aberration or polarization conversion can destroy the performance of an optical disk drive. Astigmatism of the laser, birefringence of the substrate, tilt of the objective lens (or of the disk), are some of the factors that can seriously degrade the beam quality. In this presentation, we will describe some of the theoretical and experimental results that demonstrate the various effects of the optical path on read/write/erase processes of an optical disk data storage system.