Micro-hologram Read Error Reduction via Multi-position Detection
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Solution Overview
Problem
Holographic storage systems face errors in reading bits due to interference from closely spaced bits in adjacent tracks and layers, which limits storage capacity and accuracy.
Innovation Solution
A method and system that improve bit estimation by detecting and analyzing optical returns from multiple positions, considering parameters like micro-hologram spacing, data track and layer spacing, and modulation coding, to reduce deterministic noise and enhance bit state estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bits are closely spaced in adjacent tracks and layers to increase storage capacity, then storage capacity increases, but reading accuracy deteriorates due to interference from closely spaced bits
Solution Approach 1:
The patent segments the detection process by obtaining optical returns from multiple distinct detector positions (at least two different positions) for each data bit. This segmentation allows the system to capture spatial variations in the optical signal and combine them to reduce interference effects from closely spaced adjacent bits, thereby maintaining reading accuracy while preserving high storage capacity.
Solution Approach 2:
The patent merges multiple optical return measurements from different detector positions to form a combined estimate of the bit state. By combining these segmented measurements through analysis and processing, the system achieves improved signal-to-noise ratio and reduced deterministic noise, effectively merging the benefits of multiple spatial samples to overcome interference from adjacent closely spaced bits.
2Quantity of substance
If deterministic noise from adjacent bits is present, then storage density increases, but error rates increase
Solution Approach 1:
The patent implements a feedback mechanism where the system obtains optical returns from multiple detector positions, analyzes these returns to determine bit states, and uses this information to reduce deterministic noise. The process iteratively refines the estimate of the bit state by considering measurements from multiple positions, effectively using feedback from redundant measurements to correct for interference and reduce error rates.
Solution Approach 2:
The patent applies partial action by obtaining optical returns from at least two different detector positions rather than a single position. This excessive sampling approach ensures that even if one measurement is affected by deterministic noise from adjacent bits, the additional measurements provide redundant information that can be analyzed to recover the true bit state, thereby reducing error rates while maintaining storage density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces error rates in reading optical data discs by providing a more accurate estimation of bit states, enabling higher storage capacities and improved data retrieval in holographic and other optical storage systems.
Implementation Method 1
every bit may be written as a micro-hologram, or Bragg reflection grating, typically generated by two counter-propagating focused recording beams
Implementation Method 2
holograms, which are images of three dimensional interference patterns created by the intersection of two beams of light in a photosensitive storage medium
Implementation Method 3
a signal beam which contains digitally encoded data, typically a plurality of bits, is superposed on a reference beam within the volume of the storage medium resulting in a chemical reaction which, for example, changes or modulates the refractive index of the medium within the volume
Implementation Method 4
generate an optical return, which includes light from the read beam scattered by the data bit of interest
Data Source
AI summary
The present techniques provide methods and systems reading a data bit of interest on an optical data disc with a reduced error rate. The data bit estimation may be improved by reducing deterministic noise resulting from an optical reader system and/or the optical data disc. The reader may adjust the position of a detector to detect light scattered from the disc based on parameters of known noise sources. In one embodiment, the detector may be moved vertically in relation to the data bit of interest on the optical disc. In another embodiment, more than one detector may be used to detect light scattered from a data bit of interest. In embodiments, the positioning of the detector(s) may be based on system or disc parameters, and the detected scatterings may provide a data reading, improved for an optical return from a present micro-hologram.