Investigation on upper limit of dynamic range of fiber optic interferometric sensors base on the digital heterodyne demodulation scheme

The upper limit of dynamic range (ULDR) of the fiber optic interferometric sensors (FOIS) based on the digital heterodyne demodulation scheme is investigated in this paper. According to the analysis of the demodulation process, the ULDR is restricted by two factors: the heterodyne frequency and the digital orthogonal demodulation algorithm. We discuss the influence of both the factors on the ULDR respectively in detail and give the total ULDR of the FOIS system. Experiments with the different delayed heterodyne scheme are conducted to verify the theoretical analysis and the results are consistent with the analysis conclusion.