INTERFEROMETER WITH A FIBER OPTIC HAVING A HIGH PMD IN COUPLED MODE, FIBER OPTIC GYROSCOPE (FOG), AND INERTIAL NAVIGATION SYSTEM INCLUDING SUCH A GYROSCOPE

摘要

The invention relates to a fiber optic interferometer including: a wideband optical source (1) having a decoherence time t DC; a coil comprising N turns of a fiber optic (5) with a length L; optical means capable of separating the incident beam into first and second beams coupled to first and second ends of the fiber (5) respectively, such that the first beam travels through the fiber optic in a first direction and the second beam travels through the fiber optic in a counterpropagating direction; and a detector (6) capable of detecting the intensity of the output beam. According to the invention, the fiber optic is a high polarization mode dispersion fiber optic, and the length L of the fiber optic coil is more than twice the fiber correlation length, L 2.L _c, such that the fiber operates in a coupled PMD mode, and the propagation differential group delay (DGD) between two orthogonal polarization states, accumulated over the length L of the fiber, is greater than the decoherence time of the source, DGD _{t DC}.