Crosstalk in phase-coded holographic memories using different orthogonal codes

The crosstalk noise between volume holograms multiplexed with various orthogonal phase codes is analyzed. The methods for the generation of Hadamard codes of different orders are also briefly described. Compared with a common Hadamard matrix of order of a power of 2, a Hadamard matrix whose order is not a power of 2 generally does not have a single bad code. To achieve the maximum possible storage capacity of a phase-code multiplexed holographic memory, the orthogonal phase codes need to be carefully selected by considering both the available pixel numbers of spatial light modulators and the crosstalk effect between stored holograms.