Higher NA optical pick-ups (OPUs) are being applied in optical storage system for high capacity. As the vector characteristics of the laser beam in high NA OPU play an important role in the interaction between the disc information layer and laser beam, simulations based on both vector diffraction theory and rigorous calculation of Maxell’s equations are becoming more and more important. They not only provide accurate and reliable simulation results, but also make it possible to investigate many other interesting topics e.g. the feasibility of using polarized light to increase storage density of optical discs. In this paper, a software package based on three-dimensional finite-difference time domain algorithm (3D-FDTD) is introduced to simulate readout signals. It can be used to simulate the reflection pattern for three dimension geometrical pits accurately. Moreover, because it can interface with optical design program ZEMAX, the simulation can be done for different light paths and in the presence of surface defects, which is very useful for analyzing and evaluating a practical OPU. The features of this software are expected to help explore new disc formats, understanding signals in servo path and data path, and furthermore designing a new optical pick-up etc.
The most important performance parameter for CD-R recording is the recording speed. We have achieved recording speeds of up to 56X on CD-R with a data-to-data jitter of 25 ns that is well within Orange Book specification. This jitter is achieved at zero asymmetry and with a write power margin of 20% of the optimum recording power. In this paper, we present results on a number of CD-R media. Furthermore, we discuss the influence of write strategy parameters, such as laser power level, laser pulse length, pulse shape, etc., on the recording performance of high speed CD-R.