For holographic memory, write-once type data recording has been studied by using photopolymer material. By
considering the fact that the development of optical disks has been undertaken for both the ROM type and recordable
type, there seems to exist a need to develop a ROM type disk for holographic memory. For this ROM type disk, the
desired manufacturing method will be the one used for DVD disk production. Also, from the view point of data transfer
speed, the function to reproduce data from a disk continuously rotating at high speed seems necessary.
This paper describes a phase code multiplexed ROM type holographic memory using computer generated hologram as
To improve the recording density of Polytopic multiplexed recording, we studied the spatial filtering effect from
the view points of the filter size and signal-to-noise-ratio (SNR) of the reproduced signal. The relationship
between SNR and spatial filter size is evaluated by using three dimensional model and Fresnel diffraction analysis.
By applying the Wiener filter to the reproduced signal, we can improve SNR for small spatial filter size.