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Signal processing for 35GB on a single-layer Blu-ray disc

We report on the technical progress in increasing the recording density of optical storage systems by means of improved read-channel signal processing and write-channel optimisation. The recording density increase is realized by employing PRML (Viterbi) bit detection in combination with improved timing recovery and adaptive equalisation algorithms, and by using a signal quality characterisation scheme which enables a proper control of the write process in the considered range of storage densities. The Blu-ray Disc (BD) optical disc system employing blue-violet laser with the wavelength of 405nm, objective lens with numerical aperture of 0.85 and disc cover layer thickness of 0.1mm is used as an experimental platform in our present study. Multi-track experimental results for both single-layer read-only (BD-ROM) and single-layer rewritable (BD-RE) media are presented to show the feasibility of the increased-density BD.