FUNCTIONAL POTENTIALITIES OF A FIBER SAGNAC INTERFEROMETER AS MICROPHASOMETER

The possibilities are considered to use a ring fibre interferometer as an equal-armed microphasometer for measuring phase modulation which can arise under any physical action (acoustic signal, magnetic field, etc). The conditions are analysed for obtaining the maximal detector sensitivity in the case when the optical divider with a quadrature shift is placed in a ring or when at one of the ends of the fibre ring the additional phase modulation is utilized. The potentialities of the ring phasometer are experimentally demonstrated using a model of all-fibre Sagnac interferometer at the wavelength 0,85-mu; the measured limit sensitivity is 3.10(-7) rad.