Two dimensional optimized enhanced multi diagonal code for OCDMA passive optical networks

This paper optimizes the design of two-dimensional enhanced multi diagonal (2D-EMD) code and conventional spectral/spatial (SS) optical code division multiple access system architecture for large capacity at relatively low powers. The existing 2D-EMD coding scheme is optimized by reducing the weight and length of spatial code sequence to minimize power losses across the encoding and decoding arrangement. Moreover, a complete system architecture is developed by optimizing the structures of conventional 2D SS optical line terminal (OLT) and remote node (RN) racks to reduce the use to long span optical fibers between the central office and subscribers premises. The optimized system architecture is implemented as per passive optical network (PON) specification in Optisystem and analysis is performed using several pivotal performance parameters. It is observed that optimization of the 2D-EMD (2D-OEMD) coding algorithm elevates both transmission capacity and cardinality at received powers as low as of − 10 dBm. Moreover, the new OLT and RN racks significantly reduces the length and number of optical fibers between the OLT and receiver modules. Consequently, the optimized SS 2D-OEMD system can support 192 subscribers at 2 Gbps of data each over the span of 25 km single mode fiber. Consequently, the proposed architecture can be adapted for numerous application with high bandwidth requirement including next generation PON, back bone for free space optical and fifth generation communication systems.