- Fiber optic cables used for broadband can also be used as sensors
- The Fiber Optic Sensing Association is promoting this dual usage
- For network owners, it opens up the possibility of new revenue streams
It turns out that fiber broadband isn’t just a technology that delivers fantastic symmetrical speeds for internet connectivity. The fiber optic cables can also act as giant sensors with use cases for public utilities, transportation companies and smart cities.
“I’m going to assert that the next big thing is — in addition to the fiber-to-the-home technology that we’re all deeply embroiled in — is distributed fiber optic sensing,” said Paul Dickinson, chairman of the Fiber Optic Sensing Association, on a recent webinar hosted by the Fiber Broadband Association (FBA).
Dickinson explained how Distributed Fiber Optic Sensing (DFOS) works. He said optical fibers send pulses of light many times per second. While that occurs, DFOS can measure changes in the backscattering of the light when it encounters an unusual vibration, strain or temperature change.
“Per sophisticated signal processing, you’re able to automatically monitor, detect and classify not only the location along the fiber but actually what is occurring based on libraries of information and in some cases machine learning and AI,” Dickinson said. “With this information, you’re able to report with GIS location exactly.”
He added, “It creates a very long-distance passive sensor with very high spatial resolution that’s occurring in real time.”
In the case of a sound vibration, for example, “You’re able to detect, with distributed acoustic sensing, the acoustic activity that’s many meters away orthogonally to the fiber along the entire length of the cable,” said Dickinson.
This sensing can continuously monitor things such as vehicle movement, digging activity, the health of bridges and railways, liquid and gas leaks and many other conditions.
Dickinson said, “A conduit and fiber cable that’s previously been used just for telecom and broadband capabilities, really just becomes a very valuable asset.”
The Fiber Optic Sensing Association is trying to get the word out so that fiber deployers are aware and can tap possible dual uses for their fiber.
“We want to leverage not only existing brownfield fiber cable and conduit that’s been implemented, but we want to start thinking about all the money coming through BEAD and others to how to design greenfield sensing in mind,” said Dickinson.
Kyle Glaeser, vice-chairman of the Fiber Optic Sensing Technology Outreach Committee, said, “No industry is better positioned to support and benefit from the emerging DFOS technologies than the telecom industry as more fiber networks around the world position themselves as this multi-purpose network.”
Glaeser said most problems in gas, electric and water utilities are caused either by damage from other construction work such as digging and drilling or by vandalism. He talked about some real-world examples of DFOS.
He showed a video of an excavator digging too close to some above-ground utility equipment. Nearby fiber optic sensors detected the vibrations from the noise and sent an alert to the utility.
In another example, someone opened a manhole in a street, and the fiber optic sensors detected the noise and notified the utility.
Another prime use case would be for traffic accident alerts. Glaeser noted there are already many long-haul and middle-mile networks along interstate highways, and this fiber could also be used as distributed traffic sensors.
He said a DFOS interrogator can send pulses of light along the fiber for up to 45 kilometers in either direction. The technology can provide data about the speed of each vehicle on the road and acoustic monitoring could record crashes. For this same route, it could also be monitoring adjacent utilities and other assets that are parallel to it in the right of way. “This is truly a multi-use technology,” said Glaeser.
Possible partners
Organizations who might be interested in leveraging DFOS would be utilities, transportation companies, municipalities, right-of-way owners, and interestingly, dial-before-you-dig call centers.
The 811- Common Ground Alliance estimates that it costs $30 billion per year in infrastructure damage from digging. “This technology is the only live technology that can provide preventative alerts to stop that damage from occurring,” said Dickinson.
He said Texas 811 has expressed an interest in FOSA technology.
