Information processing technique for time-domain addressing fiber Bragg grating sensor array

An electro-optical modulator was introduced to modulate the continuous light wave into pulses. An unbalance Michelson scanning interferometer was employed to transform the wavelength-shift signal reflected by the Bragg gratings to phase-shift signal. Signal coming from each sensor element was selected by controlling the on-off state of an electrical switch with a programmable delay signal generator and, therefore interrogation for time-domain addressing was achieved. Filtered with a band-pass filter, the measured can be judged by monitoring the phase-shift with a phase meter. Experiment demonstrated that the sensitivity of the 4-element sensor system, which was with a resolution of 6 nε, was 1.63 Deg/με.