Takayuki Nomoto

Signal Simulation of 25 Gbytes Read-Only Optical Disk System using a High Numerical Aperture Objective Lens

We have already developed and reported the high-definition digital-versatile-disk read-only-memory system of capacity 15 Gbytes using a blue laser and new signal processing technique. On the other hand, a high numerical-aperture system has been reported of numerical-aperture 0.85 and cover layer thickness 0.1 mm. In this paper, we examined the increase in capacity on application of our signal processing technique to the high numerical-aperture system using computer simulation. As a result, we found that a 25 Gbytes read-only-memory disk system had sufficient system margins on applying the limit equalizer and the adaptive tangential equalizer. Furthermore, if the crosstalk canceler is applied, we may achieve a system of capacity larger than 25 Gbytes.

Jitter Analysis for Land/Groove Phase Change Disk

A 22 GB optical video recording system with an objective lens of high numerical aperture (NA), a blue laser and a thin cover layer is proposed. We classify the jitter which increased by aberrations into three components for this system. We analyze the dependence of jitter components on the groove depth in detail. Furthermore, we confirm advantages of the limit equalizer (Limit-EQ) and the two-dimensional adaptive equalizer for the land/groove (L/G) phase change disk.

Analysis of the Crosstalk in a High-Density Optical Disc System

A crosstalk canceler has been proposed in order to readout a signal from a high-density optical disc. We have confirmed by the computer simulations that a crosstalk canceler is highly useful technology. Furthermore, we have calculated the readout margins of the high-density optical disk system applying a blue laser, a crosstalk canceler and some other signal processing methods.