Holographic Memories Using 2-Dimensional Phase-Code Multiplexing Method

Ezura, Megumi; Baba, Shigeyuki; Kihara, Nobuhiro

doi:10.1143/jjap.43.4954

Cited by 9 publications

(7 citation statements)

References 4 publications

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“…Each data page contained 75264 bits, which were coded in 2:4 sparse code. 4) One bright block was expressed using 3 Â 3 pixels on the SLM. The S-polarization components of the signal beam went through the Fourier-transform lens (FTL) and the square aperture eliminated the unwanted diffraction order on the Fourier-transform plane so that only the fundamental order of the signal beam was irradiated on the recording medium.…”

Section: Methodsmentioning

confidence: 99%

“…Many multiplexing methods for holographic memory have been proposed, including coaxial-type multiplexing, 3) phase-coded multiplexing, 4) random shift multiplexing, 5) and angle multiplexing. 6) The angle multiplexing method can increase the storage density when it is used together with phase conjugation reproduction 7) and polytopic multiplexing.…”

Section: Introductionmentioning

confidence: 99%

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Control of Angular Intervals for Angle-Multiplexed Holographic Memory

Kinoshita¹,

Muroi²,

Ishii³

et al. 2009

jjap

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In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10 À4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control of Angular Intervals for Angle-Multiplexed Holographic Memory

Kinoshita¹,

Muroi²,

Ishii³

et al. 2009

jjap

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“…Many types of multiplexing methods have been investigated. In addition to angle, peristrophic, and shift multiplexings introduced in the previous section, phase code multiplexing that modulates the local phase of the reference beam 14) and wavelength multiplexing that modulates the wavelength of the beam 15) have been reported. However, it is difficult to apply spherical shift and phase code multiplexings to phase conjugated holographic data storage because it requires a phase conjugated wavefront for reproducing.…”

Section: Combination Of Angle and Peristrophic Multiplexingsmentioning

confidence: 99%

[Paper] Spatial Filter and Combination of Angle and Peristrophic Multiplexings to Achieve Recording Density of 1 Tbit/inch<sup>2</sup> in Holographic Data Storage

Muroi¹,

Katano²,

Kinoshita³

et al. 2021

MTA

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We investigated the use of a spatial filter and a combination of multiplexing methods to obtain a data recording density of 1 Tbit/inch 2 . A small aperture diameter of the spatial filter can increase recording density, but the signal-to-noise ratio of the reproduced data decreases. We then investigated the minimum size of the aperture diameter under the condition where the data could be decoded. As a result, we found that the aperture diameter could be decreased to 1.2 times as large as the Nyquist width of a data page. To obtain a recording density of 1 Tbit/inch 2 , 800-data-page multiplexing was needed. We then investigated the recording conditions of angle and peristrophic multiplexings. When we recorded and reproduced data pages with 200 angle multiplexings and 4 peristrophic multiplexings, the bit error rates of the data were less than the permissive error rate, and a recording density of 1 Tbit/inch 2 could be obtained.

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“…In HDS, two-dimensional data is recorded to a recording medium 14) as a three-dimensional hologram. 15,16) Since the storage capacity depends on the diffracted efficiency of the hologram, in order to achieve a high-capacity optical disk and high readout speed, a readout technique for a weak beam due to the low diffraction efficiency of the hologram is required. For example, in the case of an optical multiple-layer disk (e.g.…”

Section: Introductionmentioning

confidence: 99%

Optical signal amplification between pages for holographic data storage

Yamazaki

Yamaguchi

2022

Jpn. J. Appl. Phys.

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This work proposes a page differential intensity amplification for optical signal amplification in the intensity multiplexing holographic data storage system. The proposed method detects the signals of four cameras and reconstructs the intensity difference between two pages. The reconstructed intensity difference is amplified by the ratio of the readout beam amplitude to the local oscillator beam amplitude. Experiments showed that the proposed method can achieve a more stable signal amplification than the conventional amplification technique. Moreover, signal detection is possible with half the light intensity of the readout beam compared to the conventional direct detection method. This corresponds to 1.4 times the recording capacity increase if the capacity is limited by M/#, or the reduction to half the readout exposure time.

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Holographic Memories Using 2-Dimensional Phase-Code Multiplexing Method

Cited by 9 publications

References 4 publications

Control of Angular Intervals for Angle-Multiplexed Holographic Memory

Control of Angular Intervals for Angle-Multiplexed Holographic Memory

[Paper] Spatial Filter and Combination of Angle and Peristrophic Multiplexings to Achieve Recording Density of 1 Tbit/inch<sup>2</sup> in Holographic Data Storage

Optical signal amplification between pages for holographic data storage

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