Fiber Bragg Grating
The FBG has great characteristics of their multiplexing capability and self-referencing. This means that several sensors, with different functions, can be connected in series on a single fiber without signals being confused and with necessary cable length becoming considerably smaller. The connection between unit and sensors is ensured via standard telecommunication fibers. A distance between unit and sensors can be up to several tens of kilometers. Therefore you can cover a large area with one unit and lots of sensors.
Being the measurement for each grating a reflected wavelength, which is an absolute parameter, there is the possibility of turning off or changing the measurement unit without the need to calibrate or determine a new zero.