ITU-T G.698.6 PDF

The purpose of this Recommendation is to provide optical interface specifications towards the realization of transversely compatible bidirectional medium-coarse wavelength division multiplexing (WDM) systems, primarily intended for mobile fronthaul and metro applications.

This Recommendation defines and provides values for optical interface parameters of point-to-point WDM applications on single-mode optical fibres through the use of the black link approach with both of the propagation directions sharing the same optical fibre or the same optical fibre pair end-to-end.

This Recommendation uses a system architecture comprising head-end equipment (HEE) connecting to the tail-end equipment (TEE) through a black link. For mobile fronthaul applications, the HEE is in a central office while the TEE is in a remote antenna site. A single bidirectional transmission fibre or a pair of fibres is used in the black link to connect the HEE to the TEE. This version of the Recommendation includes bidirectional and unidirectional WDM applications at 25 Gbit/s per channel with alternating channel wavelength spacing of 7 nm and 13 nm in the O-band.

For the applications in this version of the Recommendation, the black link does not contain optical amplifiers.

This Recommendation describes bidirectional WDM systems that include the following features:

– Operating wavelength band: the O-band;

– Nominal wavelength spacing: alternating between 7 nm and 13 nm;

– Nominal bit rate of signal channel: 25 Gbit/s;

– Nominal transmission distance: 5 km;

– Maximum capacity: 12 unidirectional channels or 6 bidirectional channels (12 total wavelengths) at 25 Gbit/s.

Specifications are organized according to application codes.