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Proceedings Paper

Experiment on two-dimensional data restoring in fault-tolerant holographic memory
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Paper Abstract

We propose a fault-tolerant holographic memory (FTHM) composed of a pair of photorefractive crystals. This memory offers not only non-destructive readout but also data restoring function by only pure optical operations without any electrical controls. In writing process, the same holographic data are simultaneously recorded as index gratings to the crystals laid out in series. In reading process, a reading beam is diffracted by the index gratings in each crystal. Here, some of the diffraction beams are detected as an output beam, and the others are used as a feedback beam. The hologram in each crystal is continuously refreshed by the feedback beam from the other crystal since the feedback beam has the same information as the original holographic data. When the data refreshing effect by the feedback beams sufficiently exceeds the erasure effect by the exposure of the reading beam, the stored data are always maintained. Furthermore, even if a certain fault such as vibration and stray beam incidence happens, the lost data in one crystal are all-optically restored as long as the corresponding holographic data remain in the other crystal. The experiment with a two-dimensional image is carried out for the purpose of checking the data restoring function in FTHM. The two-dimensional image divided in quarters is recorded as into a pair of 45°-cut BaTiO3 crystals, and the original holographic data is successfully restored by the refreshing effect in the case that a quarter of the image in the one crystal is partially lost.

Paper Details

Date Published: 17 June 2004
PDF: 8 pages
Proc. SPIE 5362, Advanced Optical and Quantum Memories and Computing, (17 June 2004); doi: 10.1117/12.528748
Show Author Affiliations
Terumasa Ito, Hokkaido Univ. (Japan)
Atsushi Okamoto, Hokkaido Univ. (Japan)
Hisatoshi Funakoshi, Hokkaido Univ. (Japan)

Published in SPIE Proceedings Vol. 5362:
Advanced Optical and Quantum Memories and Computing
Hans J. Coufal; Zameer U. Hasan, Editor(s)

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