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Title: Position feedback system for volume holographic storage media

Abstract

A method of holographic recording in a photorefractive medium wherein stored holograms may be retrieved with maximum signal-to noise ratio (SNR) is disclosed. A plurality of servo blocks containing position feedback information is recorded in the crystal and made non-erasable by heating the crystal. The servo blocks are recorded at specific increments, either angular or frequency, depending whether wavelength or angular multiplexing is applied, and each servo block is defined by one of five patterns. Data pages are then recorded at positions or wavelengths enabling each data page to be subsequently reconstructed with servo patterns which provide position feedback information. The method of recording data pages and servo blocks is consistent with conventional practices. In addition, the recording system also includes components (e.g. voice coil motor) which respond to position feedback information and adjust the angular position of the reference angle of a reference beam to maximize SNR by reducing crosstalk, thereby improving storage capacity.

Inventors:
 [1];  [2];  [3];  [2];  [4];  [5]
  1. San Francisco, CA
  2. Morgan Hill, CA
  3. Sunnyvale, CA
  4. Saratoga, CA
  5. San Jose, CA
Issue Date:
Research Org.:
Quantum Corporation (Milpitas, CA)
Sponsoring Org.:
USDOE
OSTI Identifier:
913003
Patent Number(s):
5777760
Application Number:
08/644,810
Assignee:
Quantum Corporation (Milpitas, CA)
Patent Classifications (CPCs):
G - PHYSICS G03 - PHOTOGRAPHY G03H - HOLOGRAPHIC PROCESSES OR APPARATUS
G - PHYSICS G11 - INFORMATION STORAGE G11B - INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Hays, Nathan J, Henson, James A, Carpenter, Christopher M, Akin, Jr William R., Ehrlich, Richard M, and Beazley, Lance D. Position feedback system for volume holographic storage media. United States: N. p., 1998. Web.
Hays, Nathan J, Henson, James A, Carpenter, Christopher M, Akin, Jr William R., Ehrlich, Richard M, & Beazley, Lance D. Position feedback system for volume holographic storage media. United States.
Hays, Nathan J, Henson, James A, Carpenter, Christopher M, Akin, Jr William R., Ehrlich, Richard M, and Beazley, Lance D. Tue . "Position feedback system for volume holographic storage media". United States. https://www.osti.gov/servlets/purl/913003.
@article{osti_913003,
title = {Position feedback system for volume holographic storage media},
author = {Hays, Nathan J and Henson, James A and Carpenter, Christopher M and Akin, Jr William R. and Ehrlich, Richard M and Beazley, Lance D},
abstractNote = {A method of holographic recording in a photorefractive medium wherein stored holograms may be retrieved with maximum signal-to noise ratio (SNR) is disclosed. A plurality of servo blocks containing position feedback information is recorded in the crystal and made non-erasable by heating the crystal. The servo blocks are recorded at specific increments, either angular or frequency, depending whether wavelength or angular multiplexing is applied, and each servo block is defined by one of five patterns. Data pages are then recorded at positions or wavelengths enabling each data page to be subsequently reconstructed with servo patterns which provide position feedback information. The method of recording data pages and servo blocks is consistent with conventional practices. In addition, the recording system also includes components (e.g. voice coil motor) which respond to position feedback information and adjust the angular position of the reference angle of a reference beam to maximize SNR by reducing crosstalk, thereby improving storage capacity.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {7}
}

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Works referenced in this record:

Volume holographic memory systems: techniques and architectures
journal, August 1995


Volume Holographic Storage and Retrieval of Digital Data
journal, August 1994