A fiber optic gyroscope using a low degree of polarization and polarization-maintaining light path comprises an optical meter head and a circuit signal processing part, The optical meter head comprises: a light source, a phase modulator on basis of the Y-branching optical waveguide, a detector, a coupler and an optical fiber coil, wherein the light source is alight source with low degree of polarization and single mode fiber pigtail coupling; the input terminal of phase modulator on basis of the Y-branching optical waveguide uses a single mode fiber, and the output terminal of phase modulator on basis of the Y-branching optical waveguide adopts a polarization-maintaining fiber; the input fiber pigtail of the said detector is a single mode fiber; the coupler is a 2×2 polarization independence single mode fiber coupler; the optical fiber coil is a polarization-maintaining fiber. By adopting the scheme of the low degree of polarization and polarization-maintaining light path and the signal processing methods such as all-digital closed loop control and random overmodulation etc., the present invention can reduce the effect of light path polarization crosstalk, simplify the assembling technology, enable large scale production and guarantee the good scale factor linearity performance and the lower noise level. Furthermore, by temperature modeling and compensating, the invention enables the bias of the fiber optic gyroscope to drift more slightly within the all-temperature range and therefore the fiber optic gyroscope with good performance and engineering application can be achieved.
OPTICAL FIBER GYROSCOPE WITH COMBINATION OF LOW POLARIZATION OPTICAL PATH AND POLARIZATION MAINTAINING OPTICAL PATH