The purpose of this Recommendation is to provide optical interface specifications towards the realization of transversely compatible dense wavelength division multiplexing (DWDM) systems primarily intended for metro applications which include optical amplifiers.

This Recommendation defines and provides values for single-channel optical interface parameters of physical point-to-point and ring DWDM applications on single-mode optical fibres through the use of the "black link" approach. The black links covered by this Recommendation may contain optical amplifiers.

The use of these single channel optical interfaces for DWDM systems enables the elimination of transponders which would otherwise be needed in multivendor DWDM optical transmission networks. Further details can be found in Appendix II.

This Recommendation describes single channel interfaces to DWDM systems that include the following features:

– channel frequency spacing: 50 GHz and wider (defined in [ITU-T G.694.1]);

– bit rate of signal channel: Up to 100 Gbit/s.

Specifications are organized according to application codes.