Future passive optical networks: Can CDM beat WDM?

The view commonly held by carriers and service providers is that the evolution of the next generation access network (NGAN) will be directed toward wavelength division multiplexing (WDM) passive optical network (PON) systems, that can provide symmetric multi-gigabit fiber to the home (FTTH) services. Based on recent field-trial experiments, we demonstrate that code division multiplexing (CDM) is a valid alternative, with enhanced flexibility, intrinsic data confidentiality and reduced cost equipment. Starting from a comparison between these two technologies, we report about our latest experimental results of CDM-based PON systems.