Design of Hybrid WDM/OCDM Add/Drop Filters and Its Experimental Demonstration for Passive Routing in Metropolitan and Access Integrated Network

We have proposed a newly metropolitan and access integrated network to provide services to long-reach depopulated households due to geographical difficulty, with smooth and energy-saving upgrade of the system. The feasibility of the system based on hybrid wavelength division multiplexing (WDM) and optical code division multiplexing (OCDM) is investigated from the viewpoints of add-drop multiplexing (ADM) operation and WDM/OCDM crosstalk. The ADM operation is verified when the adding, dropping, and transmitting signals are simultaneously operated, by examining the structure of multiplexer. The range of the input signal power to the multiplexer is derived. The crosstalk impact of WDM and OCDM is reduced by apodizing the filter device. By using the apodized devices, 16 × 1.25 Gb/s OCDM is successfully demonstrated at a wavelength band of 3.2 nm in C-band. From the results, the feasibility of 160-channel hybrid multiplexing in a proposed network is estimated.