Optical filters in WDM ring network architectures

This paper gives a review of the state of the art of the main optical technologies suited to optical add-drop multiplexers (OADM) in a WDM ring network with their respective potential advantages and level of maturity. Experimental results of a four port multilayer OADM are given. Then, experimentations including these filters are described with the corresponding results we have obtained. Further prospects are given for evolution and growth.