Noncoherent optical CDMA system of 2-D subtracted square codes using two code keying by eliminating the multiple use interferences

We propose the new two-dimensional subtracted square (SS) codes to achieve the new family in the spectral amplitude coding (SAC) optical code division multiple access (OCDMA) networks. The proposed codes give the multiplication between the 1-D subtracted square codes and 1-D subtracted square codes to become the code sequences of the 2-D SS codes. The proposed structure using the 2-D SS codes constructs the proposed transmitter and proposed receiver to build the code sequences of the 2-D SS codes and recovered bits using the modified cross-correlation, respectively. The proposed transmitter activates the 2-D SS codes to convert the code sequences of the 2-D SS codes. The proposed receiver gets the code sequences of the 2-D SS codes to decode the recovered bits, which cancel the interferences in the powers called the multiple user interferences (MUI). The proposed receiver transfers the cross-correlation to the modified cross-correlation, which eliminates the MUI. The modified cross-correlation takes the photodiodes to suppress the phase-induced intensity noise (PIIN), simultaneously. In numerical results, the bit error rate (BER) gets the number of the simultaneous users in the proposed system using the 2-D SS codes to accomplish the all users with 84 users. And the BER takes the data transmission rate in the proposed system using the 2-D SS codes to attain the 7.1 Gbps.