Interpixel crosstalk cancellation on holographic memory

Abstract

In holographic memory systems, there have been no practical techniques to minimize interpixel crosstalk thus far. We developed an interpixel crosstalk cancellation technique using a checkerboard phase pattern with a phase difference of π/2, which can decrease the size of the spatial filter along the Fourier plane with the signal-to-noise ratio (SNR) kept high. This interpixel crosstalk cancellation technique is simple because it requires only one phase plate in the signal beam path. We verified the effect of such a cancellation technique by simulation. The improvement of SNR is maximized to 6.5 dB when the filter size specified in the Nyquist areal ratio is approximately 1.05 in ideal optical systems with no other fixed noise. The proposed technique can improve SNR by 0.85 in an assumed monocular architecture at an actual noise intensity. This improvement of SNR is very useful for realizing high-density recording or enhancing system robustness.

The Designed Phase Mask for Suppressing the Inter-Pixel Crosstalk Noise in Intensity-Modulated Multilevel Holographic Data Storage Systems

“…To increase the recording density, the exposure area of the recording medium is often limited by inserting an aperture in the Fourier plane of the input signal [3,13,20,26,27], as shown in Figure 1. This aperture acts as a low-pass filter for the spatial frequency components of the input image, so the signal image will lose higher-order spatial frequency components and blur to a degree depending on the aperture size.…”

“…Conversely, the intensity-modulated signals have the advantage of easy detection with imaging devices but have a worse SNR than the phase-modulated signals [19]. Some researchers have addressed this problem and attempted to improve the reproduced signal [20,21]. They controlled the phase of adjacent pixels so that they were orthogonal to each other to reduce inter-pixel crosstalk noise [22,23], which is the cause of SNR deterioration.…”

Two-Dimensional Interference Estimator with Parallel Structure for Holographic Data Storage Channel

“…To reduce the noise and improve the signal-to-noise (SNR) ratio, Gu et al investigated the optimization of apertures [4]. In addition, to reduce the 2D ISI, other optical methods have been introduced for phase modulation [5,6] and polarization [7]. In addition, modulation and error correcting codes have been proposed to solve the 2D ISI [8][9][10][11].…”

[Invited Paper] Investigation of Noise Characteristics of Multivalued Signals and Estimation of Single-page Storage Density in Holographic Data Storage

“…Utilizing a multi-valued signal [13][14][15][16][17][18] instead of the binary intensity signal is one of the examples to increase the page capacity C 1page . Another example is to insert an aperture in the Fourier plane of the signal image to limit the exposed area 12,[19][20][21][22][23][24] . However, usually it will degrade the reconstructed signal quality due to the crosstalk noise and result in large bit error rate.…”