METHOD OF MEASURING PHASE SIGNAL OF DOUBLE-BEAM FIBRE-OPTIC INTERFEROMETER Russian patent published in 2021 - IPC G01B9/02 

FIELD: optics.

SUBSTANCE: invention relates to the field of fibre-optic measuring instruments and can be used to increase the accuracy of measuring a phase signal in two-beam Michelson or Mach-Zehnder interferometers and arrays of fibre-optic sensors based thereon. Method of measuring a phase signal of a double-beam fibre-optic interferometer includes irradiating its sensitive and reference arms with a main source of optical radiation with simultaneous irradiation of its support arm with an additional source of optical radiation, polarization plane of which is orthogonal to the polarization plane of the radiation of the main source, and the coherence length of the radiation is greater than the length of the optical path in the forward and reverse directions along the support arm. At that, by means of polarization multiplexing, propagation of additional source radiation in the sensitive arm is excluded, registration of two obtained interference signals, their synchronous detection and phase demodulation, and the desired phase signal is obtained by subtracting a phase signal obtained by irradiating the reference arm with an additional optical radiation source, from a phase signal obtained by irradiating it with a main source of optical radiation.

EFFECT: method increases accuracy of measuring a phase signal in one or more two-beam fiber-optic measurement interferometers by eliminating phase noise of vibroacoustic effects on the reference arm of the interferometer.

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