Holographic data storage (HDS) is a prospective, next-generation mass optical storage system. In HDS,
wave-front aberration in the optical system causes deterioration of the reconstructed signal quality. In this study, to clarify the
margin allowed for HDS drive development, the influence of aberration in the case of wave-front aberration of defocus, where
the influence of image degradation is especially high, was measured in the optical system. Further, with the aim to improve the
error rate, a finite impulse response (FIR) filter using LMMSE was applied to the image deteriorated by the wave-front
aberration. Consequently, we confirmed that the error rate can be reduced by applying the FIR filter for each modulation code.
In order to clarify the hologram recording process for the photopolymer media, we analyzed both the creation process of multiplexed hologram and diffraction characteristics of reproduction process using a Beam Propagation Method (BPM). We also conducted experiment and evaluated the multiplexed hologram recording
characteristics. By the simulation using BPM and experimental results of hologram multiplexed recording, we made clear the evaluation process of photopolymer media and recording / reproduction conditions of multiplexed holograms recording.
In holographic memories, photopolymer is a hopeful material as a recording medium. To use a photopolymer for
holographic memories as practical recording media, it is necessary to clarify the design condition of
recording/reproduction characteristics. The coupled-wave analysis (CWA) and the rigorous coupled-wave analysis
(RCWA) are widespread methods to analyze diffraction characteristics of volume holographic gratings. However,
holographic grating is more complex than simple grating that is presumed in CWA and RCWA. In this study, we
analyzed the index change of photopolymer based on a diffusion model and clarified the diffraction characteristics by
using the finite-difference time-domain (FDTD) method.