Patent ID: 7292516
Filing Date: 2007-11-06
Classification: G11B

Abstract:
1. A system for phase detection in page-based optical data storage, the system comprising: a storage medium; a photodetector sensor array positioned to detect a data page when the data page is optically read from the storage medium by mixing a signal beam with a heterodyne reference beam; a phase detection system coupled to the photodetector sensor array to process the data and to determine the most likely correct value of the bits read; a feedback control system for aligning the heterodyne reference beam with respect to the signal beam; a plurality of alignment sensors positioned about the photodetector sensor array such that differences in sensor signals are indicative of angular misalignment between the heterodyne reference beam and the signal beam; and wherein the feedback control system processes the differences in sensor signals and aligns the heterodyne reference beam with respect to the signal beam.