Ears to the Ground via Fiber

If the ground could only talk, what would it have to say? Well, probably not much as it has dirt and rocks for brains. But, give it some ears and the ground could tell us things about the sidewalks, the weather, and the surrounding environment that we would otherwise never know.

Fiber optic cable is capable of being those ears. As described in the above interview, members of the Fiber Optics Sensing Association (FOSA) have figured out how to use existing fiber optic cables to measure vibrations, strain, and temperature. Applications range from monitoring pipeline breaks to measuring cable strain to detecting people to counting traffic (see this link for a list of case studies and papers).

Fiber optic sensing works by being a good listener and reflecting back on what it hears. That is, a pulsed laser sends light down the fiber. The imperfections in the glass core of the fiber reflect some of the light back to its origination point (see Raleigh backscatter).

By detecting this light, it is possible to create a baseline signature. Then, this reference point can be compared to signatures of various activities (e.g. a person walking will cause a different amount of vibrations than a car driving by) so alerts can be provided (e.g. location of a pipeline break).

In the above interview, Kent Wardley, Chairman of FOSA, and Dave Cunningham, Vice Chairman of FOSA discuss this non-profit organization made up of industry and academia. This relatively new group (founded 2017) has parallels to and close relations with the Fiber Broadband Association (e.g., Gary Bolton of the FBA is a FOSA board member). Wardley, who is with Fotech Solutions, and Cunningham, who is with Network Integrity Systems, tout FOSA’s advocacy for and comments that influenced the federal “Dig Once” policy.

Interview Highlights:

This video was made possible by Calix.

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