[OPTICAL REVIEW Vol. 1, No. 2 (1994) 183-187]
Optimization of Mark Edge Recording Waveform for a Phase Change Rewritable Optical Disk Using a 680 nm Laser Diode
Takashi ISHIDA, Mamoru SHOJI, Yoshiyuki MIYABATA, Yasumasa SHIBATA, Eiji OHNO and Shunji OHARA
1Information and Communications Technology Laboratory, 2Materials and Devices Laboratory, Matsushita Electric Industrial Co., Ltd., 1006 Kadoma, Osaka, 571 Japan
(Accepted September 29, 1994)
A high density mark edge recording method on a phase change rewritable disk is reported. A carrier-to-noise ratio of 55 dB for a mark length of 0.55 μm is obtained by using a 680 nm, NA 0.6 head and a phase change rewritable disk. In mark edge recording, it is necessary to record each mark in correct length. A new laser power modulation pattern is proposed. This pattern consists of a first-pulse, a multi-pulse chain and a last-pulse. Both positions of the first-pulse and the last-pulse are movable. By adjusting these positions, a jitter, Σ/Tw (Tw is window margin), is improved to 6.5% in high density EFM (Eight to Fourteen Modulation) recording of 0.4 μm/bit.
Key words : mark edge recording, phase change, high density recording, optical disk, jitter, EFM