PARTIAL-RESPONSE MAXIMUM-LIKELIHOOD DETECTION METHOD FOR MAGNETOOPTICAL RECORDING

We detected bits sized at 0.237 mu m bit length and 0.85 mu m track pi tch recorded by magnetic field modulation on a magneto-optical disk wi th a 690-nm laser diode and 0.60-numerical-aperture-objective using a partial-response maximum-likelihood detection method. We confirmed tha t the optimum partial-response for this high linear density had four c oefficients of 1 by analyzing difference metrics of error critical pat hs. The recorded bits with areal density of 5.6 bit/mu m(2) were also detected at a low error rate, which combination is 0.237-mu m bit leng th and 0.75-mu m track pitch. Its write power tolerance is limited to +/-22%.