All-optical 3R regenerators: status and challenges

In the optical fibre world, 3R regeneration (Reamplifying-Reshaping-Retiming) is performed electronically at the SDH level, mainly at the boundaries of transmission systems. In a competitive context, as the physical limits of fibre communication systems become difficult to overcome, in-line 3R regenerators are being considered to improve repeater spacing or system margins. Simultaneously optical routing and switching make their way in optical networks. In this context 3R regenerators are required to insure the expandability of the network. One objective of the ACTS REPEAT project was to ascertain the feasibility of all-optical 3R regeneration and its benefits.