Validation of FBGs sensors C-PFM multiplexing and interrogation technique

In this paper, we propose an improvement of the Chirped-Pulsed Frequency Modulation (C-PFM) FBGs reading technique [8] as supported by new experimental results. The C-PFM technique, which was basically translated from its counterpart in the field of radar signal analysis, exploits the intensity modulation of the probe signal (the light traveling along the fiber in our case) by means of a sinusoid with a linearly variable frequency and a train of pulses, to improve the spatial resolution of the acquisition system. The response discrimination of the FBG sensors is achieved thanks to an infiber linear filter and a novel adaptive numerical filtering as it will be better explained in the following. Using a peculiar time window shaping (Blackman) of the light pulse we intended to improve the cross-talk features of the reading technique.