Random Signal Characteristics of Super Resolution Near Field Structure Read-Only Memory Disc
Abstract
We report the random pattern signal characteristics of the super resolution near field structure (Super-RENS) disk in a red laser optical system. (Laser wavelength 659 nm, numerical aperture 0.6) We improved the carrier to noise ratio (CNR) characteristics and the low frequency noise by optimizing the layer design and the pit structure, which results in 53 dB CNR at 173 nm pit length. It is equivalent to 50 GB capacity if it is converted by Blu-ray Disc (BD) specification according to the ratio of beam size. We also improved the readout power margin and the stability greatly by introducing the thermal control layer. The eye pattern under phase locked loop (PLL) state could be obtained through equalization adjustment (EQ). Through above improvements, we obtain the bER of 4.6× 10-4 at 50 GB level by using partial response maximum likelihood (PRML) method.
- Publication:
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Japanese Journal of Applied Physics
- Pub Date:
- February 2006
- DOI:
- 10.1143/JJAP.45.1374
- Bibcode:
- 2006JaJAP..45.1374K