A Differential Double Interference Fiber Optic Gyroscope Based on Optical Path Difference

Abstract

The invention discloses a differential double-interference type fiber optic gyroscope based on optical path difference. The differential double-interference type fiber optic gyroscope comprises a light source, a coupler, a birefringence modulator, a fiber loop, a polarization beam splitter, a first detector and a second detector; the light source and the A end of the coupler are welded together in an angle of 45 DEG at welding point O1; the C end of the coupler and the A end of the birefringence modulator are welded in an angle of 0 DEG at welding point O2; the B end and the C end of the birefringence modulator are welded with the two ends of the polarization-maintaining fiber loop in angles of 0 DEG at welding point O3 and welding point O4 respectively; the middle point O5 of the fiber loop is welded with respect to the axis in an angle of 90 DEG; the B end of the coupler and the input end of the polarization beam splitter are welded in an angle of 0 DEG at welding point O5; and the two output ends of the polarization beam splitter are welded with the first detector and the second detector respectively. The differential double-interference type fiber optic gyroscope is capable of realizing a scheme of optical path difference, and reducing nonreciprocal errors of the gyroscope. The wide spectrum light source with low coherence is employed, so that strong noise caused by various stray wave interferences which is induced by the high coherence of laser light sources is avoided.

Description

technical field [0001] The invention relates to a differential double-interference optical fiber gyroscope capable of realizing SAGNAC effect multiplication and optical path difference under the condition of constant optical fiber ring area and optical fiber length, and belongs to the technical field of optical fiber gyroscope. Background technique [0002] As a new type of inertial angular velocity sensor that is developing extremely rapidly, fiber optic gyroscope has its unique technical and performance advantages, such as all-solid-state structure, high reliability, long life; fast start-up speed, short response time; large measurement range and wide dynamic range ; Anti-shock, vibration, chemical corrosion resistance; small size, light weight, low cost; suitable for mass production, etc., have been widely used in various fields. [0003] The internationally accepted form of fiber optic gyroscope is the single interferometric type, that is, the fast axis or slow axis of a...

AI Technical Summary

Problems solved by technology

At present, the differential dual-interference fiber optic gyroscope uses a circuit differential detection scheme. Since the reciprocity of the differential double-interference fiber optic gyroscope is based on precise differences, in order to ensure the reciprocity of the gyroscope, it is necessary to ensure that the two circuits The parameter consistency of the detection circuit, which is difficult to achieve in practice, will reduce the ability of the differential double interference gyro to suppress environmental disturbances

At the same time, the current differential double-interference fiber optic gyroscope uses a narrow-spectrum light source, and the coherence length of the light wave is relatively long, resulting in increased noise such as backscattering, back reflection, and cross-coupling, which also affects the accuracy of the gyroscope.

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