METHOD OF MEASURING PHASE SIGNAL OF DOUBLE-BEAM FIBRE-OPTIC INTERFEROMETER Russian patent published in 2020 - 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 phase signal of double-beam interferometer includes generation of modulated optical signal by means of frequency modulation of optical radiation source, frequency-modulated optical signal is additionally modulated by amplitude using an amplitude modulator by feeding thereon rectangular electric pulses of constant porosity and the same amplitude and sending it to double-beam fibre-optic unbalanced interferometers - one reference and one or N-1 measuring, where N is the maximum number of double-beam fibre-optic interferometers combined into an array with time multiplexing in accordance with the optical budget of the optical circuit (N = 2, 3, 4, …), output frequency-modulated optical signals from fibre-optic interferometers are detected by photoreceiving devices performing their photoelectric conversion, the obtained electrical signals of each interferometer are converted by means of synchronous detection into sets of quadrature signals - sine and cosine signal components, using them determine the depth of frequency modulation of the signal of each interferometer, perform phase demodulation of quadrature signals of each interferometer and obtaining the desired phase signal of each measuring interferometer by subtracting the demodulated phase signal of the reference interferometer, multiplied by the ratio of the measured depth of frequency modulation in the measuring interferometer and the reference interferometer, from the demodulated phase signal of the measuring interferometer.

EFFECT: technical result is higher accuracy.

1 cl, 3 dwg