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US 5,627,664 AGranted
Holographic storage with combined orthogonal phase codes and random phase codes
AssigneeTamarack Storage Devices
InventorJahja I. Trisnadi
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Abstract
A method and apparatus for holographic storage with combined orthogonal phase codes and random phase codes are provided in which a reference beam (18) is encoded with a combination orthogonal phase code and random phase code by a phase encoder (28). A data pattern is imposed on an object beam (20) by pattern encoder (38). Both the reference beam (18) and the object beam (20) are directed to a particular stack site on a storage medium (32).
Claims20
A holographic storage system, comprising:
- a storage medium operable to store holographic images;
- a coherent light source operable to generate a reference beam and an object beam;
- a phase encoder operable to impose phase patterns on said reference beam;
- a pattern encoder operable to impose data patterns on said object beam;
- optics operable to direct said reference beam and said object beam to a site on said storage medium;
- and
- a control system operable to control said phase encoder to combine orthogonal phase patterns and random phase patterns such that at least some of said phase patterns imposed upon said reference beam comprise orthogonally encoded, random patterns, thereby increasing the number of said holographic images that can be stored on said storage medium.
4 more elements
A holographic storage system, comprising:
- a storage medium operable to store holographic images;
- a coherent light source operable to generate a reference beam and an object beam;
- a phase encoder operable to impose phase patterns on said reference beam;
- a pattern encoder operable to impose data patterns on said object beam;
- optics operable to direct said reference beam and said object beam to a site on said storage medium;
- and
- a control system operable to control said phase encoder, such that at least some of said phase patterns comprise orthogonally encoded, random patterns, thereby increasing the number of said holographic images that can be stored on said storage medium;
- wherein said phase encoder is divided into a plurality of segments, and said random patterns are orthogonally encoded onto each segment;
- and
- wherein said phase encoder includes a plurality of columns and n segments, each segment including 1/nth of the total number of columns.
7 more elements
A holographic storage system, comprising:
- a storage medium operable to store holographic images;
- a coherent light source operable to generate a reference beam and an object beam;
- a phase encoder operable to impose phase patterns on said reference beam;
- a pattern encoder operable to impose data patterns on said object beam;
- optics operable to direct said reference beam and said object beam to a site on said storage medium;
- and
- a control system operable to control said phase encoder, such that at least some of said phase patterns comprise orthogonally encoded, random patterns, thereby increasing the number of said holographic images that can be stored on said storage medium;
- wherein said phase encoder comprises a spatial light modulator having a plurality of elements, each element operable to introduce a phase shift;
- and
- wherein said phase encoder further comprises a polarizer operable to polarize light zero and n radians.
7 more elements
A method of storing data, comprising the steps of:
- generating a reference beam and an object beam;
- combining orthogonal phase patterns and random phase patterns to produce orthogonally encoded, random phase patterns, thereby increasing the number of said holographic images that can be stored on a holographic storage medium;
- imposing the orthogonally encoded, random phase patterns on the reference beam;
- imposing data patterns on the object beam;
- and
- directing the reference beam and the object beam to a site on said holographic storage medium.
3 more elements
A holographic storage system, comprising:
- a storage medium operable to store holographic images;
- a coherent light source operable to generate a reference beam;
- a phase encoder operable to impose phase patterns on said reference beam;
- optics operable to direct said reference beam to a site on said storage medium;
- a control system operable to control said phase encoder to combine orthogonal phase patterns and random phase patterns such that at least some of said phase patterns imposed upon said reference beam comprise orthogonally encoded, random patterns, thereby increasing the number of holographic images that can be stored on said storage medium;
- and
- an optical detector operable to detect a reconstructed object beam.
4 more elements
Dependencies are inferred from the claim text.