RFoG refers to Radio Frequency over Glass Fiber. It is a specific type of optical networking, that transports the RF signals that go over copper, to a Passive Optical Network (PON). It is standard ANSI/SCTE 174 2010 (pdf) of the SCTE. RFoG figures into a Hybrid fiber-coaxial network (HFC), which is the term for a broadband network that combines optical fiber with coaxial cable, with the optical fiber as the backbone, and the coax goes to the premises as the drop.
With RFoG, the coaxial portion of the HFC is changed to a Passive Optical Network (PON), which uses a single mono-mode fiber as the ‘last mile’ solution. This offers that advantage of higher bandwidth, with less interference compared to the coax that it replaces. By replacing the coax copper going to the residence, RFoG technology enables a fiber to the home (FTTH) solution, and is considered a ‘deep fiber’ network design.
Downstream and return path transmissions utilize the same fiber, but are separated on to different wavelengths of light. The downstream wavelength is typically 1550 nm, while the upstream is more variable using the 1590/1610 nm, or 1310 nm wavelengths.
RFoG deployments have been slow to date. While RFoG has the advantages of higher reliability, better scalability and higher bandwidth, the downsides of additional upfront equipment expenses, and the cost of deployment have hampered wider adoption of this otherwise promising technology.
With the inherent advantages, and despite the issues, there have been some carrier deployments to date. Of the cable carriers, notably, Comcast has used RFoG for a FTTH solution, in the Jacksonville, Florida market with fiber optical cables going directly to the user’s premises for true FTTH. Another carrier that uses RFoG is Verizon Fios, for the video portion of their service. Finally, Altice is building out their fiber network with plans (and promises) of FTTH, that is rumored to be using a variant of RFoG technology.
While RFoG still holds quite a bit of promise, it does compete with the easier to deploy DOCSIS 3.1, that requires less startup costs. While RFoG may be less expensive over the long term, with less interference, these advantages can be hard to justify to shareholders that want a return on investment for the next quarter, and not over years out, where the benefits of scalability and less maintenance pay their dividends.
RFoG remains a viable 'last mile' solution, for implementation of FTTH. Feel free to discuss opinions, experiences, and frustrations with RFoG as a last mile fiber solution.
This article was contributed by the DSLReports.com community. If you'd like to receive payment for writing content like this for our front page, please drop us a line.