Intermodal Fiber Interferometer Based on an SMSMS structure with Spectral Interrogation for Measuring External Impacts

An intermodal fiber interferometer based on the SMSMS structure, with spectral interrogation and Fourier analysis of the signals, has been experimentally studied. It has been shown that such a scheme can be considered a sensor for external impacts with two sensitive sections, which are multimode fibers of different lengths. In this paper, the Fourier analysis method of the output signals of such a scheme was used to extract information about external impacts on two sensitive sections. It is shown that external impacts can be measured by obtaining the Fourier image of the spectral transfer function and finding the phases of the spectral components corresponding to two multimode fibers. The results of measuring the external impacts using the proposed approach are presented. It is shown that the proposed approach provides independent measurements of external impacts exerted on two multimode fibers, which are sensitive elements in an intermodal fiber interferometer based on the SMSMS structure.