Fiber adoption is essential for MSOs (Multiple-System Operators) to address rising data demands. MSOs have traditionally deployed coaxial cables from headend hubs to a local node and then to “last mile” connections, distributing data to and from the subscriber homes in a cable network. While coaxial cabling has long been a staple in the upstream and downstream channels of cable networks, fiber cabling offers advantages that are more in line with modern network requirements.
A major drawback of coaxial cabling is its reliance on RF (analog) data transfer, which is slower and weaker in signal strength compared to digital transfer. Fiber cables have an obvious advantage over coaxial cables, as they can be used as a transmission medium for optical signals converted from digital/analog signals.
With this advantage, replacing coaxial cabling in favor of fiber would be ideal. However, the costs of implementing a FTTH (Fiber-To-The-Home) network are monumental and an infrastructure for establishing FTTH networks are not readily available in many neighborhoods. Local regulations and neighborhood utility restrictions make it difficult for MSOs to simply swap out coaxial cables with fiber cables in last mile connections. MSOs would also need to reconsider the role of their legacy architectures when building an expensive FTTH network.
HFC (Hybrid Fiber-Coaxial) networks are the middle ground between cable and FTTH networks. As the name suggests, HFC networks involve a hybrid mix of coaxial and fiber cabling, utilizing a FTTN (Fiber-To-The-Node) setup while continuing to use coaxial cabling for the last mile connection. A key advantage of HFC is that MSOs can simply retrofit their legacy architectures to set up an HFC network. When taking cost into account, HFC networks deliver superior performance over pure coaxial ones at a fraction of the cost of FTTH networks.
Digital return is the driving force behind HFC networks. Digital return technology is deployed at the network node to facilitate data transfer in the upstream channel. The travel path consists of analog transmission from home to the node, then digital transmission from the node back to the headend hub, hence the name digital return. Digital return modules housed in network nodes convert analog signals from the home into digital signals. Digital return SFPs are inserted into the module sockets and convert the digital signals to light, sending it across the fiber back to the headend. This simple and efficient design enables MSOs to retain their legacy architectures with simple tweaking of their network setups.
AM (Amplitude Modulation) a.k.a analog optics, and BDR (Broadband Digital Return) a.k.a digital return are two optical transport return path technologies. While the major benefits of analog optics are its simplicity, lower costs, and greater flexibility when compared with digital return, distance is a major limitation which lowers RF levels. With digital return, the output of the receiver is no longer dependent on optical input power. It allows the operator to make modifications to the optical MUX/DEMUX without altering RF levels. Also, link performance is distance independent, the number of wavelengths used is not a factor and fiber crosstalk effects do not limit performance. In summary, the pros for digital return are that signal to noise performance does not degrade with distance, redundancy is supported, service group aggregation is enabled, and less costly inventory is needed for pluggable optics.
Axiom offers a line of digital return SFPs with a wide variety of options for HFC networks. Compact and efficient, our digital return SFPs can be easily implemented in any HFC network. Axiom digital return SFPs are MSA compliant and have been thoroughly programmed and tested for guaranteed compatibility in your network architecture with some of the most popular platforms including Cisco, Arris, Aurora, and other leading brands.
CWDM and DWDM networks are increasingly popular as they enable data transfer on multiple wavelengths. This increases fiber bandwidth and allows businesses to optimize their fiber deployment. Our digital return SFP lineup offers both CWDM/DWDM-ready transceivers and transmitters with a diverse range of reach and bandwidth specifications to address the most stringent modern network requirements. Axiom digital return SFPs enable MSOs to upgrade their legacy architectures and convert them to HFC networks. MSOs can avoid having to reconstruct neighborhood grids to swap out coax for fiber while saving on costs for investing in an FTTH network.
Contact an Axiom Connectivity representative today for more details on Axiom digital return SFPs.