Demodulation of serial fibre Bragg grating sensor arrays by fourier transform spectroscopy using an over-moded laser reference

We report a Fourier Transform Spectroscopy scheme for the simultaneous demodulation of a Bragg grating sensor array and the measurement of the intra-grating spectral structure of the individual gratings of the array, based on referencing to a transversely multimode laser. The performance for this reference, relative to that of a single-mode reference, is evaluated in the context of coherence effects, temperature sensing, and high-resolution intra-grating spectral measurement. The results indicate the potential for grating demodulation across the full spectrum of the E, S, C and L optical telecommunications bands.