Identify regions/free spectral range M-sequence code to improve cardinality over AWG-based WDM/OCDMA networks

This paper presents a hybrid wavelength-division multiplexing (WDM) and optical code-division multiple-access (OCDMA) scheme over fiber to-the-home (FTTH) networks. In the proposed scheme, the total wavelength spectrum of the light source is divided into both of WDM group for identify section and OCDMA group for coded orthogonal section. In order to implement the shared arrayed-waveguide grating (AWG) encoder/decoder which exploiting in accordance with the inherent periodic free-spectral-range (FSR) interval range of the AWG router, the WDM group is used to distinguish each region configured with optical network units (ONUs) group based on the various diameter of optical line terminal (OLT) center. Moreover, the OCDMA groups are implemented with delay line matrix to obtain zero cross-correlation. Compared to conventional schemes without partition of identify section, the proposed scheme shows that the cardinality of proposed scheme approximately increased 6 times and 13 times than those of conventional scheme when the scheme is only partition number of 2 and 3 identify section, respectively. Furthermore, the proposed scheme provides more flexibility that the same identify region is assigned to the same ONU groups depending on the approximately distance from the OLT location.