Compensation of the power fluctuations in intensity-based plastic optical fiber sensors

A new technique to compensate power fluctuations occurring in intensity-based plastic optical fiber sensors is presented. The technique relies on the use of a dual-wavelength transmission over the fiber: two signals at two different wavelengths experience the same environmental perturbations, apart from the sensing region where only one signal is attenuated according to the sensing quantity. Therefore it is possible to use the other as a reference to correct the raw measure. Experimental tests show a nearly perfect compensation of both mechanical and thermal stress over the fiber. This solution is expected to ease the widespread of low-cost plastic optical fiber sensors since it enables to overcome the sensitivity to environmental perturbations while keeping the advantages of intensity-based sensors.