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A new method for constructing optical zero-correlation zone (OZCZ) codes based on the Hadamard matrix and the concatenation operation is proposed. The most important property of the obtained codes is that the periodic correlation function of the proposed codes is zero for the phase shifts within the zero-correlation zone. The structure of the proposed OZCZ code is simple and their construction is more flexible. The proposed code is expected to be useful for reducing co-channel interference in optical code division multiple access system.

This paper proposes a new class of binary zero correlation zone (ZCZ) sequence sets, in which the periodic correlation functions of the proposed sequence set is zero for the phase shifts within the zerocorrelation zone. It is shown that the proposed zero correlation zone sequence set can reach the upper bound on the ZCZ codes.

In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bound on the ZCZ sequences. The performance of the proposed sequences set in asynchronous Direct Sequence-Code Division Multiple Access (DS-CDMA) system is evaluated. In the simulation we used two types of channels: Additive White Gaussian Noise (AWGN) and frequency non-selective fading with AWGN noise. The proposed ternary ZCZ sequence sets show better results, in term of Bit Error Rate (BER), than Hayashi's ternary ZCZ sequence sets.

This paper proposes a novel method for constructing optical zero-correlation zone (OZCZ) codes based on the Mutually Orthogonal Complementary Sets (MOCS) matrix and the concatenation operation. The most important property of the obtained codes is that the periodic correlation function of the proposed codes is zero for the phase shifts within the zero-correlation zone. The procedure of construction is simple, flexible and offers increasing number of users \left( {M = {2^{n + 1}}} \right). In the other hand, we have presented a fully reconfigurable hardware implementation based on very high description language of the proposed OZCZ codes for optical code-division multiple-access encoder system. The implementation is performed on an Altera field-programmable gate arrays device using ROM memory and an up counter. The simulation results have been found satisfactory and are in conformity with the theoretical observations.

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The physical layer of an optical network is vulnerable towards various types of security threats such as physical infrastructure attacks and eavesdropping, where the security item requires more attention in front of the dramatically grows in network capacity. In this paper, authors propose a comparison in performance of zero correlation zone-Optical Code Division Multiple Access based on different confidentiality mechanisms implemented using existing optical logic components such as line selectors, wavelength convertors and XOR gates. The performance of the proposed designs in terms of log of the bit error rate (BER) as function of the received power was evaluated through OptiSystem software simulation. The achieved results demonstrate that design 3 is the best confidentiality solution in terms of received power, BER performance and architecture complexity.

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