OPTICAL-RECORDING AT 2.4 GBIT IN(2) USING A FREQUENCY-DOUBLED DIODE-LASER/

Optical recording at 2.4 Gbit/in2 has been demonstrated at both 488 nm (argon-ion laser) and at 429 nm (doubled diode laser) using TbFeCo an d CoPt multilayers on flat glass media with a soft sampled servo track ing system. The data was written using pulse width modulation (PWM), 2 /3 (1, 7) run length limited (RLL) encoding, and detection accomplishe d using a dual clock channel. Edge shifts of 3.5% of the timing window and jitters of 7% of the timing window were observed. At a data rate of 2 Mbytes/s and with data written on adjacent tracks, a bit error ra te of 10(-5) with noise margins of 10 Db and 8.5 Db were measured at 4 88 nm and 429 nm, respectively.