The standardization and deployment of pluggable optical interfaces for headend equipment offer cost and power savings to cable operators. However, implementing pluggable optical interfaces in these devices presents significant technical challenges, since the lack of standardization may result in too many combinations of interfaces to support effectively in a headend device (power, wavelengths, cards, etc.).

Because of this challenge, the following specification proposes a standard for the interfaces between a downstream laser transmitter module and its host. The module is based on the [XFP MSA], but the input will consist of RF-modulated signals that will be amplitude modulated onto an optical carrier. For the purpose of this specification, this module is referred to as XFP-RF. This pluggable XFP-RF optical transmitter module could be integrated into headend equipment, such as a Converged Cable Access Platform (CCAP), a Cable Modem Termination System (CMTS) an Edge QAM modulator, or a forward optical transmitter shelf, reducing the need for devices dedicated to forward lasers. The XFP-RF optical transmitter module will function as a downstream laser for the output of cable edge devices.

This specification will focus on the communications, electrical, and mechanical interfaces for the XFP-RF optical transmitter module. Unless otherwise noted, requirements within this specification apply both to the transmitter module and its host.