Interrogation of a dual-fibre-Bragg-grating sensor using an arrayed waveguide grating

In this paper, we consider the possibility of improving the accuracy of a solid-state fiber Bragg grating (FBG) interrogation system by using two, instead of one, FBGs inscribed on the same location of the fiber, with a small difference in the peak wavelength that each reflects. Signal processing can be applied to the outputs of the photodetectors that are connected to an arrayed waveguide grating to provide a linear response from the sensor. We demonstrate here that this method reduces errors when compared to the setup employing a single FBG with the same bandwidth as the dual sensor.