We report the new data reproducing scheme for high density over 40GB per layer with a commercial Blu-ray
recordable disc. bER of 10-5 and 10-4 with 42.5GB and 45GB were experimentally obtained respectively using this new
data reproducing scheme which shows the possibility of achieving 50GB with a commercial single-layer Blu-ray disc.
We also propose a new evaluation parameter which is necessary for high density.
We report the readout stability improvement results of super-resolution near field structure (Super-RENS) write-once
read-many (WORM) disk at a blue laser optical system. (Laser wavelength 405nm, numerical aperture 0.85) By using diffusion barrier structure (GeSbTe sandwiched by GeN) and high transition temperature recording material (BaTiO<sub>3</sub>), material diffusion of phase change layer and recording mark degradation were greatly improved during high power (Pr=2.0mW) readout process up to 1X10<sup>5</sup> times.
To realize more than 15GB data capacity using blue laser diode, suppression of the adjacent track crosstalk may be one of the key technology. Several methods have been proposed for the adjacent track crosstalk cancellation using 2 beams or 3 beams. Kasazumi et.al. have proposed one method with coaxial dual beams. Although they can reduce the adjacent track crosstalk, it is not easy to get enough optical power from the objective lens for recording. In this paper, we propose new method of the readout signal generation to reduce the adjacent track crosstalk.
In an optical pick-up for high areal density recording using Nd:YAG SHG (second harmonic generation) green laser, the stability of a servo mechanism may be deteriorated easily due to many optical elements and long optical path. We propose a new stable servo method employing a differential critical-angle prism. This method showed one order of higher stability than conventional astigmatic servo method to the chief ray tilt. We obtained more than a CNR of 48dB even in case of the large chief ray tilt with 0.5 micrometers mark length on MO recording layer, which is close to the case of no chief ray tilt.
Conference Committee Involvement (1)
Optical Data Storage Topical Meeting 2004
18 April 2004 | Monterey, California, United States