Optimal Design of Track Pattern for Holographic Read-Only Memory

Abstract

An optimal track format for a holographic read-only-memory (ROM) disk is proposed that minimizes the intertrack crosstalk and stores conventional optical disk pit patterns with a density equivalent to that of digital versatile discs (DVDs) in a single holographic layer. To quantify the effect of intertrack crosstalk for the cases of variations in track width and pitch, we defined signal-to-crosstalk ratio (SCR) as a criterion to find the optimal track format. A numerical simulation is used to calculate SCR as a function of track width and pitch. The simulation results show that SCR varies with track width, pitch and pit length. When the track width, pitch, and minimum pit length are 0.5, 0.74, and 0.4 m, respectively, we can set a minimum pit length with a maximum SCR so that the storage density of each layer of the holographic ROM is equivalent to that of DVDs.