Browse Prior Art Database

Exposure Control in Holographic Storage

IP.com Disclosure Number: IPCOM000103052D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 30K

Publishing Venue

IBM

Related People

Dube, R: AUTHOR [+4]

Abstract

Performance and reliability of a holographic data storage device depends strongly on the exposure times used for writing and reading in the holographic medium. Exposure time can be precisely controlled by the use of reserved pel positions in each hologram (fiduciary pels) which are set to known values and used for real-time evaluation of exposure.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Exposure Control in Holographic Storage

      Performance and reliability of a holographic data storage
device depends strongly on the exposure times used for writing and
reading in the holographic medium.  Exposure time can be precisely
controlled by the use of reserved pel positions in each hologram
(fiduciary pels) which are set to known values and used for real-time
evaluation of exposure.

      During writing of a hologram, there is a simultaneous readout
of the data as it is written.  For control of exposure during
writing, the quality of the read signal from the fiduciary pels can
be monitored continuously, and writing can be terminated when the
monitored signal indicates that the data has been written well enough
to provide a reliable readout.

      Also, during reading, the quality of the read signal from the
fiduciary pels can be monitored continuously, and reading can be
terminated when these representative pels indicate that a
satisfactory signal-to-noise ratio has been achieved.

      Disclosed anonymously.