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Proceedings Paper

Real-time adaptive encoding for 3D optical memories
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Paper Abstract

There are a variety of factors that can limit the set of allowable code words that are useable on an optical memory block. In this paper, we will primarily consider inter- symbol interference (ISI) and the noise margins required to represent an individual bit. Fo example, code words must maintain a specific topological separation of '1' bits so that ISI does not raise the intensity of neighboring '0's' above a pre-set threshold. Typically this is accomplished by a static encoding that uses a pre-selected set of code words based on these properties of the storage media and the optical system. Alternatively, our approach provides for a dynamic analysis of all data currently stored in the region surrounding a particular block and defines the allowable code words uniquely for each block. We assume the existence of a 'smart' read head that is capable of analyzing a page of data and calculating the allowable codes in real-time based on the actual data in the surrounding region. We use point-spread function based mathematical model for optical readout system to evaluate and carry out data encoding. Our experiments show 81% spatial utilization while recent publications present only 45% utilization.

Paper Details

Date Published: 23 January 2002
PDF: 8 pages
Proc. SPIE 4459, Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications VII, and Optical Data Storage, (23 January 2002); doi: 10.1117/12.454039
Show Author Affiliations
Leo Selavo, Univ. of Pittsburgh (United States)
Donald M. Chiarulli, Univ. of Pittsburgh (United States)
Steven Peter Levitan, Univ. of Pittsburgh (United States)


Published in SPIE Proceedings Vol. 4459:
Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications VII, and Optical Data Storage
Shizhuo Yin; Francis T. S. Yu; Hans J. Coufal; Hans J. Coufal, Editor(s)

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