USE OF WDM TECHNIQUE IN SDH NETWORKS

This paper proposes the introduction of the multiwavelength technique in the three layers of a SDH-based network. In the trunk layer, wavele ngth division multiplexing (WDM) takes advantage of the optical parall elism in a single fiber. Cross-connection can. be achieved either pass ively (i.e., with tunable filters) or by means of wavelength converter s. The latter solution, which offers high flexibility, was implemented in a 4 x 4 optical routing element. In the junction network, the feas ibility of a three-station WDM self-healing ring was demonstrated. Fin ally, in the access network, synchronous burst access and time and wav elength division multiplexing (T/WDM) switching is proposed to offer s ervice flexibility to the subscribers.