Abstract

Collinear holographic memory is one of the candidates of post Blu-ray disc system. This system has several advantages comparing to other holographic memory systems [1]. For examples, collinear system is quite stable because both reference and signal waves passes through common optical elements. It is a kind of common-path interferometer. Also, recording media of same physical size as CD can be used because this system requires only one objective lens and reflection geometry can be used to write and read holograms which contain the digital page data. The matured servo technologies for conventional optical discs can also be used due to its geometry of the optical head. We have been studying the write and read characteristics of this system, and revealed that the main limiting factors for the recording density is wavelength of the light, numerical aperture (NA) of the objective lens, coding efficiency of the data, and the degree of multiplexing. Among these four factors, theoretical limit of the degree of multiplexing has not been clear yet. It is limited by the dynamic range of the recording media, and decrease of the signal to noise ratio (SNR) due to the intra- and inter- page crosstalk noises. In this paper, we will present the estimation of these noises with our model for the collinear holographic memory system.

© 2009 IEEE