scope:

The purpose of this Recommendation is to define wavelength ranges reserved for additional service signals to be overlaid via wavelength division multiplexing (WDM) in gigabit-capable passive optical networks (G-PONs) for maximizing the value of optical distribution networks (ODNs).

For this purpose, this Recommendation defines and provides:

- wavelength ranges to be reserved; and

- X/S tolerance in PON optical network units (ONUs).

Appendices I and II provide:

- a general reference diagram of coexistence elements, and sample parameters of a discrete WDM filter that combines and isolates up/down signals of passive optical network (PON) systems, radio frequency (RF) signals and optical time-domain reflectometer (OTDR) signals at the optical line termination (OLT) side;

- examples of wavelength allocation for next generation access (NGA) services and video distribution services.

The physical media dependent (PMD) layer specification for G-PON in the absence of an enhancement band is defined in [ITU-T G.984.2]. PMD layer specifications for G-PON in the presence of enhancement bands are defined by the combination of [ITU-T G.984.2] and this Recommendation. Whenever a parameter specified in [ITU-T G.984.2] is not explicitly mentioned in this Recommendation, its value given in [ITU-T G.984.2] remains valid. Whenever a parameter is specified in both this Recommendation and [ITU-T G.984.2], the specification in this Recommendation takes precedence.