Approach to a higher data transfer rate in 15-Gb DWDD-MO recording

We have studied high-density MO (magneto-optical) recording using a DWDD (domain wall displacement detection) medium with a red diode laser and a 0.60-NA objective lens. Using the same optical parameters of a DVD (digital versatile disc) system, we obtained an acceptable bit error rate of 4.8/spl times/10/sup -4/ with an areal density of 11 Gbit/in/sup 2/ and a data-transfer rate of 20 Mbit/sec. In addition, we analyzed the noise components to achieve much higher transfer-rate recording.