Let's consult the almitghy answer gods at Google(how does that thing work anyway?).. First result on https://www.google.com
"Exploitation of specialty fibers for disruptive sensor technology"
Grammar for the win! No dots to see here folks..
http://www.laserfocusworld.com/articles/print/volume-52/issue-01/features/photonics-products-specialty-fibers-fibers-for-sensing-extend-their-reach.html
Optical fibers used for sensing can measure temperature, strain, pressure, sound, electrical current, and even the 3D shape of the fiber itself.
As opposed to telecommunications fiber-optic systems, which are designed to minimize the influence of the surrounding environment on light propagation through the fiber, a fiber-optic sensing system is simply doing what it's supposed to when its performance is affected by its surroundings.
Fiber-optic systems used for sensing can measure environmental influences such as temperature or strain either continuously along the fiber, or at discrete points defined by fiber components. Other types of fiber sensors can measure physical movements such as rotation, as in a fiber gyroscope. The ruggedness and narrow physical path of optical fibers make them ideal for use as sensors in harsh and remote environments.