Abstract
Reducing the size of data pattern on optical disk to increase the storage capacity is definitely a direction of development for storage medium. Therefore, high NA (Numerical Aperture) objective lens would be employed to generate tiny spot for the readout process. However, this would make the defocus tolerance rigorous at the same time. Therefore, focusing is still a critical issue in new generation optical storage system.This thesis is devoted to investigate the effects of imperfect conditions within an optical pickup such as lens aberrations on the spot formation. Besides, the variation of focusing error signal (S-curve) due to the presence of disk tilt aberrations is also studied in this work. Wave optics and aberration theory are introduced in this thesis to calculate the optical field distribution and MATLAB is used to perform our own-developed program codes and plot the simulation results. On the other hand, a commercial software, DIFFRACT, is used to verify our simulation results.