By: Brad Nikkari, VP of Access Networking Products at ATX Networks

The opportunities and incentives for internet service providers (ISP’s) to extend broadband services to unserved or underserved communities have never been greater. Closing the so-called “digital divide” and elevating the reach and robustness of broadband services have become targets of massive public funding, attracting proposals of billions of dollars since the end of 2020, in turn providing additional incentives for ISP’s and others to pursue these opportunities.

But extending the reach of robust broadband services can be complicated by historic barriers, including business-model and technology-related obstacles. The good news is that cable operators now have access to optical transport equipment and technology that can overcome these obstacles to assist ISP’s in expanding their service footprints to rural and remote communities by extending the reach of their optical networks.

The broadband industry is transforming, perhaps at the most rapid pace in its history. Operators are facing several significant technological and architectural decisions that are likely to impact the evolution of their networks and competitive standings for the next decade.

A promising and potentially insomnia-curing development is the opportunity for ISP’s to add millions of new subscribers by increasing their penetration of communities that are currently located significant distances from existing cable infrastructure. One explanation for the low penetration of broadband into rural regions is that service providers have not had a great deal of incentive in the past to pursue opportunities in remote regions. That’s because, in addition to operators having to spend more to reach subscribers in remote and sparsely populated regions than they do in urban areas, the density of subscribers per mile is lower and the service fees per subscriber that would be accepted is historically lower than urban customers in terms of average revenue per user (ARPU).

But that dynamic appears to be changing. Rural areas are increasingly hungry for robust broadband for several reasons, including taking advantage of recent innovations in digital farming, education, and employment that now require a big broadband pipe. A 2021 FCC study, titled Impact of Broadband Penetration on U.S. Farm Productivity, identified a direct correlation between crop yields and faster broadband services. It turns out, the FCC study suggests, that if you build robust broadband connectivity near cornfields in Iowa, profit will come.

In addition, extending broadband services to rural areas represents one of the best remaining opportunities for operators to expand their subscriber ranks organically. With the regulatory climate potentially moving toward taking a harder look at acquisitions, cable operators are more likely to pursue rural expansion to grow their broadband footprint. In many ways, rural expansion is the next customer acquisition frontier for many operators.

The major reason for millions of unserved and underserved homes and businesses in just the United States alone is that it’s difficult for communications service providers to make it worth their while to extend their networks to rural and often sparsely populated regions of the world. Historically, the issue has been the expense of building out their networks from a technology standpoint. Analog optics have long posed a challenge, as the technology is not particularly well-suited for long distances. In addition, long-distance optical links often require physical locations, or hubsites, to be constructed along the route.

A second big problem, as mentioned previously, is the perception of a lack of lucrative payoffs from rural regions. When you put these two things together, the reality is that past efforts to broadband-enable remote regions were plagued by a technology foundation that was just a little too wobbly to support a viable business plan.

So, what’s changed?

On the business side of the equation, work from home (WFH) policies have raised the broadband bar for remote workers, who now require faster connections to keep pace with colleagues in urban areas or those commuting to the office. In addition, farms and other businesses located in rural areas are hungry for speed and bandwidth to realize cutting-edge productivity gains. What all of this adds up to is that the potential financial reward for serving remote communities has improved significantly in the past couple of years.

Those changes on the business side have, fortunately, developed concurrently with progress on the technology side. Technology improvements or breakthroughs in the past few years, such as digital optics, multiwavelength transport, and more efficient dispersion compensation in digital optical amplifiers, have helped to make it possible for service providers to extend their broadband services more cost-effectively than they could in the past.

In long-reach deployments, operators will typically mux multiple DWDM wavelengths onto a single fiber to efficiently extract the maximum capacity from available fiber, connecting to a series of remote PON OLTs (Optical Line Terminals). Simple passive mux devices at the terminal ends of each fiber path cannot be used in these scenarios. The major limitation of this approach is that optical link budgets are strictly limited and, depending on the number of wavelengths, splices, adds and drops, as well as other factors, the maximum reach of the optical link may be only 20 kilometers (12 miles) or less.

That’s where new breakthroughs in digital amplification come in. Using next-gen EDFA technology, ISP’s can extend digitized links deep into the network, even beyond 180 kilometers (111 miles). The more effective the amplifier, the greater the potential to reduce the number of amplifiers required to reach a remote community.

How service providers compensate for chromatic dispersion over the length of their optical networks is also a critical factor in the overall cost of long-reach networks. 100G coherent optics can reach long distances without optical dispersion compensation. But these cost far more than commoditized 10G 80km optics, which need optical dispersion compensation. An integrated dispersion compensation approach delivers extended reach and improved performance compared to pre- or post-stage dispersion compensation modules (DCM’s). The improved performance of integrated compensation includes the ability to increase spacing between amplifiers and a reduction in EDFA repeater stations, resulting in a reduction in overall link cost and deployment flexibility.

Another critical attribute of a cost-efficient digital optical transport solution is passive add/drop capabilities. The ability to drop wavelengths at multiple locations along an optical path is especially valuable in long-reach deployment scenarios, as the number of homes passed per mile in rural communities can be fewer than 10. This capability significantly reduces overall costs and network complexity and helps to overcome many of the historic barriers to entries that discouraged ISP’s from extending services to remote locations.

Several major ISP’s are currently leveraging next-gen digital optical transport and amplifiers to bring high-speed digital connections of 10 Gbps to rural communities, where they are extended over the last mile to subscribers and businesses using PON technology.