A Generation Method of a Two-Dimensional Optical ZCZ Sequence with the Zero-Correlation Zone (4n – 2) × (4n – 2)

In this paper, we propose a new generation method of a two-dimensional (2D) optical zero-correlation zone (ZCZ) sequence with the size of ZCZ (4n – 2) × (4n – 2). The 2D optical ZCZ sequence consists of pairs of a binary sequence which takes 1 or 0 and a bi-phase sequence which takes 1 or −1, and has a zero-correlation zone in the two-dimensional correlation function. Because of these properties, the 2D optical ZCZ sequence can be used for optical code-division multiple access (OCDMA) system using an LED array having a plurality of light-emitting elements arranged in a lattice pattern. The OCDMA system using the 2D optical ZCZ sequence can increase the data rate and can suppress interference by the light of adjacent LEDs. By using the proposed generation method, we can improve the peak value of the autocorrelation function of the sequence. This means that the BER performance of the OCDMA system using the sequence can be imnroved.