Coaxial Holographic Memory with Designed Reference Pattern on the Basis of Nyquist Aperture for High Density Recording

Abstract

We propose the designed reference pattern on the basis of the Nyquist aperture for a coaxial holographic memory and investigate its recording performance by numerical simulations. By using the designed reference pattern, the Fourier power spectrum of a reference beam spreads uniformly within the Nyquist aperture, thereby an interference efficiency, a signal-to-noise ratio (SNR) and a symbol error rate (SER) are improved relative to conventional method with a random binary phase mask. Moreover, in the case of applying the 1.25 times aperture than the Nyquist size, the proposed method can record data pages with higher SNR and lower SER than that of conventional method with 2 times aperture than the Nyquist size. Numerical results imply that our proposed method can record data pages at a smaller area of recording media than that of conventional method.

Recent advances in holographic data storage

“…In 1998, Sony Corporation presented a similar concept using shift multiplexing [24]. Following this, Optware Corporation and a number of others in the industry began developing systems based on these concepts [14,[25][26][27][28][29][30][31][32]. Collinear technologies have significant advantages compared with 2-axis holography: good write and read performance, uniform shift selectivity for both radial and tangential directions, and fairly large system tolerances have been experimentally reported [14,25,26].…”