Using Fiber as a Sensor

I am an admitted science nerd. I love to spend time crawling through scientific research papers. I don’t always understand the nuances since scientific papers are often written in severe jargon, but I’ve always been fascinated by scientific research, because it presages the technology of a few decades from now.

I ran across research by Nokia Bell Labs concerning using fiber as a sensor. Scientists there have been exploring ways to interpret the subtle changes that happen in a long strand of fiber strand. The world is suddenly full of fiber strands, and scientists want to know if they can discern any usable real-life data from measuring changes in fiber.

They are not looking at the transmission of the light inside the data. Fiber electronics have been designed to isolate the light signal from external stimuli. We don’t get a degraded signal when a fiber cable is swaying in the wind. We probably don’t marvel enough about the steady and predictable nature of a fiber light signal.

The research is exploring if the physical attributes of the fiber can be used to predict problems in the network before they occur. If a network operator knows that a certain stretch of fiber is under duress, then steps can be taken to address the issues long before there is a fiber outage. Developing ways to interpret the stresses on fiber would alone justify the research many times over.

But scientists can foresee a much wider range of sensor capabilities. Consider a fiber strung across a bridge. It’s hard to measure tiny shifts in the steel infrastructure in a bridge. However, a fiber cable across the bridge can sense and measure subtle changes in the tensions on the bridge and might be able to understand the way that a bridge is shifting long before it becomes physically obvious.

There is already some physical sensing used to monitor underseas fibers – but more can be done. The fiber can possibly measure changes in temperature, current flows, and seismic activity for the full length of these long fibers. Scientists have developed decent sensors for measuring underground faults on land, but it’s much harder to do in the depths of the open ocean.

To test the capabilities to measure and interpret changes to fiber, Bell Lab scientists built a 524-kilometer fiber route between Gothenburg and Karlstad in Sweden as the first test bed for the technology. This will allow them to try to measure a wide range of environmental data to see what can or cannot be done with the sensing technology.

It’s hard to know where this research might go, which is always the case with pure research. It’s not hard to imagine uses if the technology works as hoped. Fiber might be able to identify and pinpoint small forest fires long before they’ve spread and grown larger. Fibers might serve as an early warning system for underground earthquakes long before we’d know about them in the traditional way. The sensing might be useful as a way to identify minor damage to fiber – we know about fiber cuts, but there is often no feedback today from lesser damages to fiber that can still grow to finally result in an outage.

2 replies on “Using Fiber as a Sensor”

Thanks Doug. I often want to comment on your excellent postings. In addition to my years of networked communities/societies work, I have been involved in arts/sciences projects for over 50 years. That now includes creative explorations of Photonics, including fiber optic sensing and laser interferometry. One of the revelations of our moving into the photonic (and bio-genetic) eras is that light is moving us from our current digital processing techniques, into a new analogue processing (quantum) era, that most of us are not aware of. Digital (on/off) thinking has permeated our minds and actions, but is about to be phased toward ‘wave functions’ and the entropic nature of complexity and ‘uncertainty’. This way of thinking and technology development has barely been part of our networking considerations and planning. Will we find enlightenment?

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