The increasing prevalence of interconnected technology has led to the rise of the smart city—a city that collects and uses data to optimize the management of resources, services, and other assets. The more data collected, the more efficient this management becomes. But the demand for data means a demand for data collection tools—sensors—and fiber may be one of the most powerful assets in the toolbox.
Enter distributed fiber optic sensing (DFOS) technology. It uses fiber to take environmental measurements, turning a city-spanning telecom fiber network into an array of sensors.
Paul Dickinson, PhD, chairman of the Fiber Optic Sensing Association (FOSA) and director of business development at Dura-Line, explained more during the FOSA Technology Outreach Committee webinar “What’s the Killer App for Large-Scale Fiber Sensing Deployment?”
“Optical fiber is at the core of smart cities in so many instances,” said Dickinson. “Optical fiber maximizes performance; it’s the only technology that functions not only in direct connections but as the backbone to wireless to support high-bandwidth and low latency, which is critical in the aspiration of becoming a smart city.”
Dickinson explained that fiber’s reliability, sustainability, and future-readiness make it ideal, if not a necessity, for smart cities. He compared a city-wide fiber network to a capillary system in which everything is connected or will soon be connected.
According to Dickinson, ubiquitous connection relies on sensors—things like cameras, microphones, etc.
“In order to provide the sensitivity and capability to make a city smart, you have to have a high density of these sensors,” he said. “We probably can’t have enough individual sensors to monitor our environment.”
Because of its ability to convert fiber into sensors, Dickinson believes DFOS technology will be the next big innovation in the fiber to the home (FTTH) and IoT realms.
The backscatter
DFOS works by registering and analyzing the pulses of light traveling through fiber optic cables. But instead of looking at the light at the receiving end, DFOS technology registers and analyzes the backscatter—light that is sent back to the source. And it’s very sensitive. Fiber can detect the vibrations and movements of things like vehicles, excavator work, and even someone digging with a shovel. And it works with traditional G.652 fiber variants as well as specialty fiber designed for greater sensitivity.
“You’re able to detect the activity that’s many meters away from the fiber that’s along the entire length of the cable,” said Dickinson. “So, it creates a very long-distance passive sensor with very high spatial resolution that’s occurring in real-time.”
DFOS technology can be used to monitor vibrations, as is the case of distributed acoustic sensing, as well as strain and temperature.
“Through sophisticated signal processing that’s improved tremendously over the last decade, you’re able to automatically monitor, detect, and classify not only the location along the fiber but actually what is occurring based upon libraries of information and, in some cases, machine learning and AI,” said Dickinson. “Through this activity, you’re able to report with GIS location exactly and then take actionable response.”
DFOS everywhere
Kyle Glaeser, vice-chairman of the FOSA technology outreach committee and director of emerging networks at Underline, described how three broad utility market verticals—utilities, transportation, and telecom—can implement and benefit from DFOS technology.
“Critical utilities are the lifeblood of our communities today,” he said. “It’s easy to take for granted the importance of water and power utilities until there is an interruption in the service. Damage to these critical utilities is not only CapEx intensive and time intensive to repair, but it can cause a widespread health and safety issue.”
Glaeser said the utilities face constant threats, ranging from right-of-way construction, unpermitted digging, and natural disasters to targeted physical or cyber-attacks. If the utilities are within range of fiber optic cables, DFOS technology can sense these issues and send alerts about the activity and its exact location. This can also be used to protect the network assets themselves.
“In the event of network vandalism,” said Glaeser, “the exact time and acoustic profiles are collected with the exact location. If the vandalism is not able to be stopped, at the very least, a much more comprehensive investigation can take place.”
This same concept also translates to transportation.
“Increasing road safety and reducing fatalities is a complex formula that factors in road conditions, traffic patterns, accident awareness, and emergency response,” said Glaeser. “DFOS can allow transportation industries to get real-time data across a large section of road network and provide analysis for traffic flows, road conditions, accident response preparedness, and public safety entities, as well as inform large scale infrastructure capital where to make its most compelling investments.”
Glaeser said the telecom industry is uniquely positioned to support and benefit emerging DFOS technologies.
“As more and more fiber networks around the world position themselves as multipurpose networks, DFOS provides a path for network owners to take advantage of their existing and future assets to deliver these assets into communities everywhere,” he said. “This presents opportunities for fiber network owners to increase their client base, drive new revenues, and also improve their internal operations and network integrity.”
The DFOS evolution
According to Dickinson, DFOS technology dates to the early 2000s, when it was used for military purposes; it then moved into commercial spaces like oil and gas pipelines.
“It’s evolving into utilities, telecommunications, roads, and structures, and creating a smart infrastructure platform that’s going to enable the smart cities,” he said.
This, Dickinson said, is where the potential lies.
“There’s tremendous opportunity to integrate this into existing systems,” he said. “In many cases, it’s not a standalone system: the identification of locations on a map in combination with video and pointing cameras in the right direction, existing SCADA operations, and even drones and such, enables this to become a valuable part of the portfolio that will improve life safety, damage prevention, and operational awareness. So, the functionality for a conduit and fiber cable that’s been previously used just for telecom and broadcom capabilities really becomes a valuable asset.”
He also noted that, while there are opportunities with existing assets, it is important to keep DFOS in mind when building new assets.
Glaeser believes DFOS advances will follow the course of other telecom technologies. He said that typically, innovation in this space occurs first in data centers, then moves to long haul and intranet networks, then middle mile networks, and finally last mile and metro networks.
“A common cause for this path of innovation is a result of the CapEx associated with new technologies,” he said. “It is more capital-efficient to deploy higher cost equipment in the core of the network than at the edge. DFOS solutions are likely to follow this same trajectory. However, the applications that are available today will benefit every network segment. As DFOS solutions become less capital intensive, and more and more entities recognize the benefits of this data, new revenue streams will appear, and last-mile DFOS solutions will be deployed in mass.”
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Hayden Beeson
Hayden Beeson is a writer and editor with over seven years of experience in a variety of industries. Prior to joining Lightwave and Broadband Technology Report, he was the associate editor of Architectural SSL and LEDs Magazine.